--- /dev/null
+GETTING STARTED WITH KMEMCHECK
+==============================
+
+Vegard Nossum <vegardno@ifi.uio.no>
+
+
+Contents
+========
+0. Introduction
+1. Downloading
+2. Configuring and compiling
+3. How to use
+3.1. Booting
+3.2. Run-time enable/disable
+3.3. Debugging
+3.4. Annotating false positives
+4. Reporting errors
+5. Technical description
+
+
+0. Introduction
+===============
+
+kmemcheck is a debugging feature for the Linux Kernel. More specifically, it
+is a dynamic checker that detects and warns about some uses of uninitialized
+memory.
+
+Userspace programmers might be familiar with Valgrind's memcheck. The main
+difference between memcheck and kmemcheck is that memcheck works for userspace
+programs only, and kmemcheck works for the kernel only. The implementations
+are of course vastly different. Because of this, kmemcheck is not as accurate
+as memcheck, but it turns out to be good enough in practice to discover real
+programmer errors that the compiler is not able to find through static
+analysis.
+
+Enabling kmemcheck on a kernel will probably slow it down to the extent that
+the machine will not be usable for normal workloads such as e.g. an
+interactive desktop. kmemcheck will also cause the kernel to use about twice
+as much memory as normal. For this reason, kmemcheck is strictly a debugging
+feature.
+
+
+1. Downloading
+==============
+
+kmemcheck can only be downloaded using git. If you want to write patches
+against the current code, you should use the kmemcheck development branch of
+the tip tree. It is also possible to use the linux-next tree, which also
+includes the latest version of kmemcheck.
+
+Assuming that you've already cloned the linux-2.6.git repository, all you
+have to do is add the -tip tree as a remote, like this:
+
+ $ git remote add tip git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git
+
+To actually download the tree, fetch the remote:
+
+ $ git fetch tip
+
+And to check out a new local branch with the kmemcheck code:
+
+ $ git checkout -b kmemcheck tip/kmemcheck
+
+General instructions for the -tip tree can be found here:
+http://people.redhat.com/mingo/tip.git/readme.txt
+
+
+2. Configuring and compiling
+============================
+
+kmemcheck only works for the x86 (both 32- and 64-bit) platform. A number of
+configuration variables must have specific settings in order for the kmemcheck
+menu to even appear in "menuconfig". These are:
+
+ o CONFIG_CC_OPTIMIZE_FOR_SIZE=n
+
+ This option is located under "General setup" / "Optimize for size".
+
+ Without this, gcc will use certain optimizations that usually lead to
+ false positive warnings from kmemcheck. An example of this is a 16-bit
+ field in a struct, where gcc may load 32 bits, then discard the upper
+ 16 bits. kmemcheck sees only the 32-bit load, and may trigger a
+ warning for the upper 16 bits (if they're uninitialized).
+
+ o CONFIG_SLAB=y or CONFIG_SLUB=y
+
+ This option is located under "General setup" / "Choose SLAB
+ allocator".
+
+ o CONFIG_FUNCTION_TRACER=n
+
+ This option is located under "Kernel hacking" / "Tracers" / "Kernel
+ Function Tracer"
+
+ When function tracing is compiled in, gcc emits a call to another
+ function at the beginning of every function. This means that when the
+ page fault handler is called, the ftrace framework will be called
+ before kmemcheck has had a chance to handle the fault. If ftrace then
+ modifies memory that was tracked by kmemcheck, the result is an
+ endless recursive page fault.
+
+ o CONFIG_DEBUG_PAGEALLOC=n
+
+ This option is located under "Kernel hacking" / "Debug page memory
+ allocations".
+
+In addition, I highly recommend turning on CONFIG_DEBUG_INFO=y. This is also
+located under "Kernel hacking". With this, you will be able to get line number
+information from the kmemcheck warnings, which is extremely valuable in
+debugging a problem. This option is not mandatory, however, because it slows
+down the compilation process and produces a much bigger kernel image.
+
+Now the kmemcheck menu should be visible (under "Kernel hacking" / "kmemcheck:
+trap use of uninitialized memory"). Here follows a description of the
+kmemcheck configuration variables:
+
+ o CONFIG_KMEMCHECK
+
+ This must be enabled in order to use kmemcheck at all...
+
+ o CONFIG_KMEMCHECK_[DISABLED | ENABLED | ONESHOT]_BY_DEFAULT
+
+ This option controls the status of kmemcheck at boot-time. "Enabled"
+ will enable kmemcheck right from the start, "disabled" will boot the
+ kernel as normal (but with the kmemcheck code compiled in, so it can
+ be enabled at run-time after the kernel has booted), and "one-shot" is
+ a special mode which will turn kmemcheck off automatically after
+ detecting the first use of uninitialized memory.
+
+ If you are using kmemcheck to actively debug a problem, then you
+ probably want to choose "enabled" here.
+
+ The one-shot mode is mostly useful in automated test setups because it
+ can prevent floods of warnings and increase the chances of the machine
+ surviving in case something is really wrong. In other cases, the one-
+ shot mode could actually be counter-productive because it would turn
+ itself off at the very first error -- in the case of a false positive
+ too -- and this would come in the way of debugging the specific
+ problem you were interested in.
+
+ If you would like to use your kernel as normal, but with a chance to
+ enable kmemcheck in case of some problem, it might be a good idea to
+ choose "disabled" here. When kmemcheck is disabled, most of the run-
+ time overhead is not incurred, and the kernel will be almost as fast
+ as normal.
+
+ o CONFIG_KMEMCHECK_QUEUE_SIZE
+
+ Select the maximum number of error reports to store in an internal
+ (fixed-size) buffer. Since errors can occur virtually anywhere and in
+ any context, we need a temporary storage area which is guaranteed not
+ to generate any other page faults when accessed. The queue will be
+ emptied as soon as a tasklet may be scheduled. If the queue is full,
+ new error reports will be lost.
+
+ The default value of 64 is probably fine. If some code produces more
+ than 64 errors within an irqs-off section, then the code is likely to
+ produce many, many more, too, and these additional reports seldom give
+ any more information (the first report is usually the most valuable
+ anyway).
+
+ This number might have to be adjusted if you are not using serial
+ console or similar to capture the kernel log. If you are using the
+ "dmesg" command to save the log, then getting a lot of kmemcheck
+ warnings might overflow the kernel log itself, and the earlier reports
+ will get lost in that way instead. Try setting this to 10 or so on
+ such a setup.
+
+ o CONFIG_KMEMCHECK_SHADOW_COPY_SHIFT
+
+ Select the number of shadow bytes to save along with each entry of the
+ error-report queue. These bytes indicate what parts of an allocation
+ are initialized, uninitialized, etc. and will be displayed when an
+ error is detected to help the debugging of a particular problem.
+
+ The number entered here is actually the logarithm of the number of
+ bytes that will be saved. So if you pick for example 5 here, kmemcheck
+ will save 2^5 = 32 bytes.
+
+ The default value should be fine for debugging most problems. It also
+ fits nicely within 80 columns.
+
+ o CONFIG_KMEMCHECK_PARTIAL_OK
+
+ This option (when enabled) works around certain GCC optimizations that
+ produce 32-bit reads from 16-bit variables where the upper 16 bits are
+ thrown away afterwards.
+
+ The default value (enabled) is recommended. This may of course hide
+ some real errors, but disabling it would probably produce a lot of
+ false positives.
+
+ o CONFIG_KMEMCHECK_BITOPS_OK
+
+ This option silences warnings that would be generated for bit-field
+ accesses where not all the bits are initialized at the same time. This
+ may also hide some real bugs.
+
+ This option is probably obsolete, or it should be replaced with
+ the kmemcheck-/bitfield-annotations for the code in question. The
+ default value is therefore fine.
+
+Now compile the kernel as usual.
+
+
+3. How to use
+=============
+
+3.1. Booting
+============
+
+First some information about the command-line options. There is only one
+option specific to kmemcheck, and this is called "kmemcheck". It can be used
+to override the default mode as chosen by the CONFIG_KMEMCHECK_*_BY_DEFAULT
+option. Its possible settings are:
+
+ o kmemcheck=0 (disabled)
+ o kmemcheck=1 (enabled)
+ o kmemcheck=2 (one-shot mode)
+
+If SLUB debugging has been enabled in the kernel, it may take precedence over
+kmemcheck in such a way that the slab caches which are under SLUB debugging
+will not be tracked by kmemcheck. In order to ensure that this doesn't happen
+(even though it shouldn't by default), use SLUB's boot option "slub_debug",
+like this: slub_debug=-
+
+In fact, this option may also be used for fine-grained control over SLUB vs.
+kmemcheck. For example, if the command line includes "kmemcheck=1
+slub_debug=,dentry", then SLUB debugging will be used only for the "dentry"
+slab cache, and with kmemcheck tracking all the other caches. This is advanced
+usage, however, and is not generally recommended.
+
+
+3.2. Run-time enable/disable
+============================
+
+When the kernel has booted, it is possible to enable or disable kmemcheck at
+run-time. WARNING: This feature is still experimental and may cause false
+positive warnings to appear. Therefore, try not to use this. If you find that
+it doesn't work properly (e.g. you see an unreasonable amount of warnings), I
+will be happy to take bug reports.
+
+Use the file /proc/sys/kernel/kmemcheck for this purpose, e.g.:
+
+ $ echo 0 > /proc/sys/kernel/kmemcheck # disables kmemcheck
+
+The numbers are the same as for the kmemcheck= command-line option.
+
+
+3.3. Debugging
+==============
+
+A typical report will look something like this:
+
+WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (ffff88003e4a2024)
+80000000000000000000000000000000000000000088ffff0000000000000000
+ i i i i u u u u i i i i i i i i u u u u u u u u u u u u u u u u
+ ^
+
+Pid: 1856, comm: ntpdate Not tainted 2.6.29-rc5 #264 945P-A
+RIP: 0010:[<ffffffff8104ede8>] [<ffffffff8104ede8>] __dequeue_signal+0xc8/0x190
+RSP: 0018:ffff88003cdf7d98 EFLAGS: 00210002
+RAX: 0000000000000030 RBX: ffff88003d4ea968 RCX: 0000000000000009
+RDX: ffff88003e5d6018 RSI: ffff88003e5d6024 RDI: ffff88003cdf7e84
+RBP: ffff88003cdf7db8 R08: ffff88003e5d6000 R09: 0000000000000000
+R10: 0000000000000080 R11: 0000000000000000 R12: 000000000000000e
+R13: ffff88003cdf7e78 R14: ffff88003d530710 R15: ffff88003d5a98c8
+FS: 0000000000000000(0000) GS:ffff880001982000(0063) knlGS:00000
+CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
+CR2: ffff88003f806ea0 CR3: 000000003c036000 CR4: 00000000000006a0
+DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
+DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400
+ [<ffffffff8104f04e>] dequeue_signal+0x8e/0x170
+ [<ffffffff81050bd8>] get_signal_to_deliver+0x98/0x390
+ [<ffffffff8100b87d>] do_notify_resume+0xad/0x7d0
+ [<ffffffff8100c7b5>] int_signal+0x12/0x17
+ [<ffffffffffffffff>] 0xffffffffffffffff
+
+The single most valuable information in this report is the RIP (or EIP on 32-
+bit) value. This will help us pinpoint exactly which instruction that caused
+the warning.
+
+If your kernel was compiled with CONFIG_DEBUG_INFO=y, then all we have to do
+is give this address to the addr2line program, like this:
+
+ $ addr2line -e vmlinux -i ffffffff8104ede8
+ arch/x86/include/asm/string_64.h:12
+ include/asm-generic/siginfo.h:287
+ kernel/signal.c:380
+ kernel/signal.c:410
+
+The "-e vmlinux" tells addr2line which file to look in. IMPORTANT: This must
+be the vmlinux of the kernel that produced the warning in the first place! If
+not, the line number information will almost certainly be wrong.
+
+The "-i" tells addr2line to also print the line numbers of inlined functions.
+In this case, the flag was very important, because otherwise, it would only
+have printed the first line, which is just a call to memcpy(), which could be
+called from a thousand places in the kernel, and is therefore not very useful.
+These inlined functions would not show up in the stack trace above, simply
+because the kernel doesn't load the extra debugging information. This
+technique can of course be used with ordinary kernel oopses as well.
+
+In this case, it's the caller of memcpy() that is interesting, and it can be
+found in include/asm-generic/siginfo.h, line 287:
+
+281 static inline void copy_siginfo(struct siginfo *to, struct siginfo *from)
+282 {
+283 if (from->si_code < 0)
+284 memcpy(to, from, sizeof(*to));
+285 else
+286 /* _sigchld is currently the largest know union member */
+287 memcpy(to, from, __ARCH_SI_PREAMBLE_SIZE + sizeof(from->_sifields._sigchld));
+288 }
+
+Since this was a read (kmemcheck usually warns about reads only, though it can
+warn about writes to unallocated or freed memory as well), it was probably the
+"from" argument which contained some uninitialized bytes. Following the chain
+of calls, we move upwards to see where "from" was allocated or initialized,
+kernel/signal.c, line 380:
+
+359 static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
+360 {
+...
+367 list_for_each_entry(q, &list->list, list) {
+368 if (q->info.si_signo == sig) {
+369 if (first)
+370 goto still_pending;
+371 first = q;
+...
+377 if (first) {
+378 still_pending:
+379 list_del_init(&first->list);
+380 copy_siginfo(info, &first->info);
+381 __sigqueue_free(first);
+...
+392 }
+393 }
+
+Here, it is &first->info that is being passed on to copy_siginfo(). The
+variable "first" was found on a list -- passed in as the second argument to
+collect_signal(). We continue our journey through the stack, to figure out
+where the item on "list" was allocated or initialized. We move to line 410:
+
+395 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
+396 siginfo_t *info)
+397 {
+...
+410 collect_signal(sig, pending, info);
+...
+414 }
+
+Now we need to follow the "pending" pointer, since that is being passed on to
+collect_signal() as "list". At this point, we've run out of lines from the
+"addr2line" output. Not to worry, we just paste the next addresses from the
+kmemcheck stack dump, i.e.:
+
+ [<ffffffff8104f04e>] dequeue_signal+0x8e/0x170
+ [<ffffffff81050bd8>] get_signal_to_deliver+0x98/0x390
+ [<ffffffff8100b87d>] do_notify_resume+0xad/0x7d0
+ [<ffffffff8100c7b5>] int_signal+0x12/0x17
+
+ $ addr2line -e vmlinux -i ffffffff8104f04e ffffffff81050bd8 \
+ ffffffff8100b87d ffffffff8100c7b5
+ kernel/signal.c:446
+ kernel/signal.c:1806
+ arch/x86/kernel/signal.c:805
+ arch/x86/kernel/signal.c:871
+ arch/x86/kernel/entry_64.S:694
+
+Remember that since these addresses were found on the stack and not as the
+RIP value, they actually point to the _next_ instruction (they are return
+addresses). This becomes obvious when we look at the code for line 446:
+
+422 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
+423 {
+...
+431 signr = __dequeue_signal(&tsk->signal->shared_pending,
+432 mask, info);
+433 /*
+434 * itimer signal ?
+435 *
+436 * itimers are process shared and we restart periodic
+437 * itimers in the signal delivery path to prevent DoS
+438 * attacks in the high resolution timer case. This is
+439 * compliant with the old way of self restarting
+440 * itimers, as the SIGALRM is a legacy signal and only
+441 * queued once. Changing the restart behaviour to
+442 * restart the timer in the signal dequeue path is
+443 * reducing the timer noise on heavy loaded !highres
+444 * systems too.
+445 */
+446 if (unlikely(signr == SIGALRM)) {
+...
+489 }
+
+So instead of looking at 446, we should be looking at 431, which is the line
+that executes just before 446. Here we see that what we are looking for is
+&tsk->signal->shared_pending.
+
+Our next task is now to figure out which function that puts items on this
+"shared_pending" list. A crude, but efficient tool, is git grep:
+
+ $ git grep -n 'shared_pending' kernel/
+ ...
+ kernel/signal.c:828: pending = group ? &t->signal->shared_pending : &t->pending;
+ kernel/signal.c:1339: pending = group ? &t->signal->shared_pending : &t->pending;
+ ...
+
+There were more results, but none of them were related to list operations,
+and these were the only assignments. We inspect the line numbers more closely
+and find that this is indeed where items are being added to the list:
+
+816 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
+817 int group)
+818 {
+...
+828 pending = group ? &t->signal->shared_pending : &t->pending;
+...
+851 q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
+852 (is_si_special(info) ||
+853 info->si_code >= 0)));
+854 if (q) {
+855 list_add_tail(&q->list, &pending->list);
+...
+890 }
+
+and:
+
+1309 int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
+1310 {
+....
+1339 pending = group ? &t->signal->shared_pending : &t->pending;
+1340 list_add_tail(&q->list, &pending->list);
+....
+1347 }
+
+In the first case, the list element we are looking for, "q", is being returned
+from the function __sigqueue_alloc(), which looks like an allocation function.
+Let's take a look at it:
+
+187 static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
+188 int override_rlimit)
+189 {
+190 struct sigqueue *q = NULL;
+191 struct user_struct *user;
+192
+193 /*
+194 * We won't get problems with the target's UID changing under us
+195 * because changing it requires RCU be used, and if t != current, the
+196 * caller must be holding the RCU readlock (by way of a spinlock) and
+197 * we use RCU protection here
+198 */
+199 user = get_uid(__task_cred(t)->user);
+200 atomic_inc(&user->sigpending);
+201 if (override_rlimit ||
+202 atomic_read(&user->sigpending) <=
+203 t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur)
+204 q = kmem_cache_alloc(sigqueue_cachep, flags);
+205 if (unlikely(q == NULL)) {
+206 atomic_dec(&user->sigpending);
+207 free_uid(user);
+208 } else {
+209 INIT_LIST_HEAD(&q->list);
+210 q->flags = 0;
+211 q->user = user;
+212 }
+213
+214 return q;
+215 }
+
+We see that this function initializes q->list, q->flags, and q->user. It seems
+that now is the time to look at the definition of "struct sigqueue", e.g.:
+
+14 struct sigqueue {
+15 struct list_head list;
+16 int flags;
+17 siginfo_t info;
+18 struct user_struct *user;
+19 };
+
+And, you might remember, it was a memcpy() on &first->info that caused the
+warning, so this makes perfect sense. It also seems reasonable to assume that
+it is the caller of __sigqueue_alloc() that has the responsibility of filling
+out (initializing) this member.
+
+But just which fields of the struct were uninitialized? Let's look at
+kmemcheck's report again:
+
+WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (ffff88003e4a2024)
+80000000000000000000000000000000000000000088ffff0000000000000000
+ i i i i u u u u i i i i i i i i u u u u u u u u u u u u u u u u
+ ^
+
+These first two lines are the memory dump of the memory object itself, and the
+shadow bytemap, respectively. The memory object itself is in this case
+&first->info. Just beware that the start of this dump is NOT the start of the
+object itself! The position of the caret (^) corresponds with the address of
+the read (ffff88003e4a2024).
+
+The shadow bytemap dump legend is as follows:
+
+ i - initialized
+ u - uninitialized
+ a - unallocated (memory has been allocated by the slab layer, but has not
+ yet been handed off to anybody)
+ f - freed (memory has been allocated by the slab layer, but has been freed
+ by the previous owner)
+
+In order to figure out where (relative to the start of the object) the
+uninitialized memory was located, we have to look at the disassembly. For
+that, we'll need the RIP address again:
+
+RIP: 0010:[<ffffffff8104ede8>] [<ffffffff8104ede8>] __dequeue_signal+0xc8/0x190
+
+ $ objdump -d --no-show-raw-insn vmlinux | grep -C 8 ffffffff8104ede8:
+ ffffffff8104edc8: mov %r8,0x8(%r8)
+ ffffffff8104edcc: test %r10d,%r10d
+ ffffffff8104edcf: js ffffffff8104ee88 <__dequeue_signal+0x168>
+ ffffffff8104edd5: mov %rax,%rdx
+ ffffffff8104edd8: mov $0xc,%ecx
+ ffffffff8104eddd: mov %r13,%rdi
+ ffffffff8104ede0: mov $0x30,%eax
+ ffffffff8104ede5: mov %rdx,%rsi
+ ffffffff8104ede8: rep movsl %ds:(%rsi),%es:(%rdi)
+ ffffffff8104edea: test $0x2,%al
+ ffffffff8104edec: je ffffffff8104edf0 <__dequeue_signal+0xd0>
+ ffffffff8104edee: movsw %ds:(%rsi),%es:(%rdi)
+ ffffffff8104edf0: test $0x1,%al
+ ffffffff8104edf2: je ffffffff8104edf5 <__dequeue_signal+0xd5>
+ ffffffff8104edf4: movsb %ds:(%rsi),%es:(%rdi)
+ ffffffff8104edf5: mov %r8,%rdi
+ ffffffff8104edf8: callq ffffffff8104de60 <__sigqueue_free>
+
+As expected, it's the "rep movsl" instruction from the memcpy() that causes
+the warning. We know about REP MOVSL that it uses the register RCX to count
+the number of remaining iterations. By taking a look at the register dump
+again (from the kmemcheck report), we can figure out how many bytes were left
+to copy:
+
+RAX: 0000000000000030 RBX: ffff88003d4ea968 RCX: 0000000000000009
+
+By looking at the disassembly, we also see that %ecx is being loaded with the
+value $0xc just before (ffffffff8104edd8), so we are very lucky. Keep in mind
+that this is the number of iterations, not bytes. And since this is a "long"
+operation, we need to multiply by 4 to get the number of bytes. So this means
+that the uninitialized value was encountered at 4 * (0xc - 0x9) = 12 bytes
+from the start of the object.
+
+We can now try to figure out which field of the "struct siginfo" that was not
+initialized. This is the beginning of the struct:
+
+40 typedef struct siginfo {
+41 int si_signo;
+42 int si_errno;
+43 int si_code;
+44
+45 union {
+..
+92 } _sifields;
+93 } siginfo_t;
+
+On 64-bit, the int is 4 bytes long, so it must the the union member that has
+not been initialized. We can verify this using gdb:
+
+ $ gdb vmlinux
+ ...
+ (gdb) p &((struct siginfo *) 0)->_sifields
+ $1 = (union {...} *) 0x10
+
+Actually, it seems that the union member is located at offset 0x10 -- which
+means that gcc has inserted 4 bytes of padding between the members si_code
+and _sifields. We can now get a fuller picture of the memory dump:
+
+ _----------------------------=> si_code
+ / _--------------------=> (padding)
+ | / _------------=> _sifields(._kill._pid)
+ | | / _----=> _sifields(._kill._uid)
+ | | | /
+-------|-------|-------|-------|
+80000000000000000000000000000000000000000088ffff0000000000000000
+ i i i i u u u u i i i i i i i i u u u u u u u u u u u u u u u u
+
+This allows us to realize another important fact: si_code contains the value
+0x80. Remember that x86 is little endian, so the first 4 bytes "80000000" are
+really the number 0x00000080. With a bit of research, we find that this is
+actually the constant SI_KERNEL defined in include/asm-generic/siginfo.h:
+
+144 #define SI_KERNEL 0x80 /* sent by the kernel from somewhere */
+
+This macro is used in exactly one place in the x86 kernel: In send_signal()
+in kernel/signal.c:
+
+816 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
+817 int group)
+818 {
+...
+828 pending = group ? &t->signal->shared_pending : &t->pending;
+...
+851 q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
+852 (is_si_special(info) ||
+853 info->si_code >= 0)));
+854 if (q) {
+855 list_add_tail(&q->list, &pending->list);
+856 switch ((unsigned long) info) {
+...
+865 case (unsigned long) SEND_SIG_PRIV:
+866 q->info.si_signo = sig;
+867 q->info.si_errno = 0;
+868 q->info.si_code = SI_KERNEL;
+869 q->info.si_pid = 0;
+870 q->info.si_uid = 0;
+871 break;
+...
+890 }
+
+Not only does this match with the .si_code member, it also matches the place
+we found earlier when looking for where siginfo_t objects are enqueued on the
+"shared_pending" list.
+
+So to sum up: It seems that it is the padding introduced by the compiler
+between two struct fields that is uninitialized, and this gets reported when
+we do a memcpy() on the struct. This means that we have identified a false
+positive warning.
+
+Normally, kmemcheck will not report uninitialized accesses in memcpy() calls
+when both the source and destination addresses are tracked. (Instead, we copy
+the shadow bytemap as well). In this case, the destination address clearly
+was not tracked. We can dig a little deeper into the stack trace from above:
+
+ arch/x86/kernel/signal.c:805
+ arch/x86/kernel/signal.c:871
+ arch/x86/kernel/entry_64.S:694
+
+And we clearly see that the destination siginfo object is located on the
+stack:
+
+782 static void do_signal(struct pt_regs *regs)
+783 {
+784 struct k_sigaction ka;
+785 siginfo_t info;
+...
+804 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
+...
+854 }
+
+And this &info is what eventually gets passed to copy_siginfo() as the
+destination argument.
+
+Now, even though we didn't find an actual error here, the example is still a
+good one, because it shows how one would go about to find out what the report
+was all about.
+
+
+3.4. Annotating false positives
+===============================
+
+There are a few different ways to make annotations in the source code that
+will keep kmemcheck from checking and reporting certain allocations. Here
+they are:
+
+ o __GFP_NOTRACK_FALSE_POSITIVE
+
+ This flag can be passed to kmalloc() or kmem_cache_alloc() (therefore
+ also to other functions that end up calling one of these) to indicate
+ that the allocation should not be tracked because it would lead to
+ a false positive report. This is a "big hammer" way of silencing
+ kmemcheck; after all, even if the false positive pertains to
+ particular field in a struct, for example, we will now lose the
+ ability to find (real) errors in other parts of the same struct.
+
+ Example:
+
+ /* No warnings will ever trigger on accessing any part of x */
+ x = kmalloc(sizeof *x, GFP_KERNEL | __GFP_NOTRACK_FALSE_POSITIVE);
+
+ o kmemcheck_bitfield_begin(name)/kmemcheck_bitfield_end(name) and
+ kmemcheck_annotate_bitfield(ptr, name)
+
+ The first two of these three macros can be used inside struct
+ definitions to signal, respectively, the beginning and end of a
+ bitfield. Additionally, this will assign the bitfield a name, which
+ is given as an argument to the macros.
+
+ Having used these markers, one can later use
+ kmemcheck_annotate_bitfield() at the point of allocation, to indicate
+ which parts of the allocation is part of a bitfield.
+
+ Example:
+
+ struct foo {
+ int x;
+
+ kmemcheck_bitfield_begin(flags);
+ int flag_a:1;
+ int flag_b:1;
+ kmemcheck_bitfield_end(flags);
+
+ int y;
+ };
+
+ struct foo *x = kmalloc(sizeof *x);
+
+ /* No warnings will trigger on accessing the bitfield of x */
+ kmemcheck_annotate_bitfield(x, flags);
+
+ Note that kmemcheck_annotate_bitfield() can be used even before the
+ return value of kmalloc() is checked -- in other words, passing NULL
+ as the first argument is legal (and will do nothing).
+
+
+4. Reporting errors
+===================
+
+As we have seen, kmemcheck will produce false positive reports. Therefore, it
+is not very wise to blindly post kmemcheck warnings to mailing lists and
+maintainers. Instead, I encourage maintainers and developers to find errors
+in their own code. If you get a warning, you can try to work around it, try
+to figure out if it's a real error or not, or simply ignore it. Most
+developers know their own code and will quickly and efficiently determine the
+root cause of a kmemcheck report. This is therefore also the most efficient
+way to work with kmemcheck.
+
+That said, we (the kmemcheck maintainers) will always be on the lookout for
+false positives that we can annotate and silence. So whatever you find,
+please drop us a note privately! Kernel configs and steps to reproduce (if
+available) are of course a great help too.
+
+Happy hacking!
+
+
+5. Technical description
+========================
+
+kmemcheck works by marking memory pages non-present. This means that whenever
+somebody attempts to access the page, a page fault is generated. The page
+fault handler notices that the page was in fact only hidden, and so it calls
+on the kmemcheck code to make further investigations.
+
+When the investigations are completed, kmemcheck "shows" the page by marking
+it present (as it would be under normal circumstances). This way, the
+interrupted code can continue as usual.
+
+But after the instruction has been executed, we should hide the page again, so
+that we can catch the next access too! Now kmemcheck makes use of a debugging
+feature of the processor, namely single-stepping. When the processor has
+finished the one instruction that generated the memory access, a debug
+exception is raised. From here, we simply hide the page again and continue
+execution, this time with the single-stepping feature turned off.
+
+kmemcheck requires some assistance from the memory allocator in order to work.
+The memory allocator needs to
+
+ 1. Tell kmemcheck about newly allocated pages and pages that are about to
+ be freed. This allows kmemcheck to set up and tear down the shadow memory
+ for the pages in question. The shadow memory stores the status of each
+ byte in the allocation proper, e.g. whether it is initialized or
+ uninitialized.
+
+ 2. Tell kmemcheck which parts of memory should be marked uninitialized.
+ There are actually a few more states, such as "not yet allocated" and
+ "recently freed".
+
+If a slab cache is set up using the SLAB_NOTRACK flag, it will never return
+memory that can take page faults because of kmemcheck.
+
+If a slab cache is NOT set up using the SLAB_NOTRACK flag, callers can still
+request memory with the __GFP_NOTRACK or __GFP_NOTRACK_FALSE_POSITIVE flags.
+This does not prevent the page faults from occurring, however, but marks the
+object in question as being initialized so that no warnings will ever be
+produced for this object.
+
+Currently, the SLAB and SLUB allocators are supported by kmemcheck.
F: include/linux/kgdb.h
F: kernel/kgdb.c
+KMEMCHECK
+P: Vegard Nossum
+M: vegardno@ifi.uio.no
+P Pekka Enberg
+M: penberg@cs.helsinki.fi
+L: linux-kernel@vger.kernel.org
+S: Maintained
+
KMEMLEAK
P: Catalin Marinas
M: catalin.marinas@arm.com
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_BZIP2
select HAVE_KERNEL_LZMA
+ select HAVE_ARCH_KMEMCHECK
config OUTPUT_FORMAT
string
endif
endif
+# Don't unroll struct assignments with kmemcheck enabled
+ifeq ($(CONFIG_KMEMCHECK),y)
+ KBUILD_CFLAGS += $(call cc-option,-fno-builtin-memcpy)
+endif
+
# Stackpointer is addressed different for 32 bit and 64 bit x86
sp-$(CONFIG_X86_32) := esp
sp-$(CONFIG_X86_64) := rsp
* Documentation/DMA-API.txt for documentation.
*/
+#include <linux/kmemcheck.h>
#include <linux/scatterlist.h>
#include <linux/dma-debug.h>
#include <linux/dma-attrs.h>
dma_addr_t addr;
BUG_ON(!valid_dma_direction(dir));
+ kmemcheck_mark_initialized(ptr, size);
addr = ops->map_page(hwdev, virt_to_page(ptr),
(unsigned long)ptr & ~PAGE_MASK, size,
dir, NULL);
{
struct dma_map_ops *ops = get_dma_ops(hwdev);
int ents;
+ struct scatterlist *s;
+ int i;
BUG_ON(!valid_dma_direction(dir));
+ for_each_sg(sg, s, nents, i)
+ kmemcheck_mark_initialized(sg_virt(s), s->length);
ents = ops->map_sg(hwdev, sg, nents, dir, NULL);
debug_dma_map_sg(hwdev, sg, nents, ents, dir);
dma_addr_t addr;
BUG_ON(!valid_dma_direction(dir));
+ kmemcheck_mark_initialized(page_address(page) + offset, size);
addr = ops->map_page(dev, page, offset, size, dir, NULL);
debug_dma_map_page(dev, page, offset, size, dir, addr, false);
--- /dev/null
+#ifndef ASM_X86_KMEMCHECK_H
+#define ASM_X86_KMEMCHECK_H
+
+#include <linux/types.h>
+#include <asm/ptrace.h>
+
+#ifdef CONFIG_KMEMCHECK
+bool kmemcheck_active(struct pt_regs *regs);
+
+void kmemcheck_show(struct pt_regs *regs);
+void kmemcheck_hide(struct pt_regs *regs);
+
+bool kmemcheck_fault(struct pt_regs *regs,
+ unsigned long address, unsigned long error_code);
+bool kmemcheck_trap(struct pt_regs *regs);
+#else
+static inline bool kmemcheck_active(struct pt_regs *regs)
+{
+ return false;
+}
+
+static inline void kmemcheck_show(struct pt_regs *regs)
+{
+}
+
+static inline void kmemcheck_hide(struct pt_regs *regs)
+{
+}
+
+static inline bool kmemcheck_fault(struct pt_regs *regs,
+ unsigned long address, unsigned long error_code)
+{
+ return false;
+}
+
+static inline bool kmemcheck_trap(struct pt_regs *regs)
+{
+ return false;
+}
+#endif /* CONFIG_KMEMCHECK */
+
+#endif
return pte_flags(a) & (_PAGE_PRESENT | _PAGE_PROTNONE);
}
+static inline int pte_hidden(pte_t pte)
+{
+ return pte_flags(pte) & _PAGE_HIDDEN;
+}
+
static inline int pmd_present(pmd_t pmd)
{
return pmd_flags(pmd) & _PAGE_PRESENT;
#define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */
#define _PAGE_BIT_UNUSED1 9 /* available for programmer */
#define _PAGE_BIT_IOMAP 10 /* flag used to indicate IO mapping */
-#define _PAGE_BIT_UNUSED3 11
+#define _PAGE_BIT_HIDDEN 11 /* hidden by kmemcheck */
#define _PAGE_BIT_PAT_LARGE 12 /* On 2MB or 1GB pages */
#define _PAGE_BIT_SPECIAL _PAGE_BIT_UNUSED1
#define _PAGE_BIT_CPA_TEST _PAGE_BIT_UNUSED1
#define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL)
#define _PAGE_UNUSED1 (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED1)
#define _PAGE_IOMAP (_AT(pteval_t, 1) << _PAGE_BIT_IOMAP)
-#define _PAGE_UNUSED3 (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED3)
#define _PAGE_PAT (_AT(pteval_t, 1) << _PAGE_BIT_PAT)
#define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)
#define _PAGE_SPECIAL (_AT(pteval_t, 1) << _PAGE_BIT_SPECIAL)
#define _PAGE_CPA_TEST (_AT(pteval_t, 1) << _PAGE_BIT_CPA_TEST)
#define __HAVE_ARCH_PTE_SPECIAL
+#ifdef CONFIG_KMEMCHECK
+#define _PAGE_HIDDEN (_AT(pteval_t, 1) << _PAGE_BIT_HIDDEN)
+#else
+#define _PAGE_HIDDEN (_AT(pteval_t, 0))
+#endif
+
#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
#define _PAGE_NX (_AT(pteval_t, 1) << _PAGE_BIT_NX)
#else
* No 3D Now!
*/
+#ifndef CONFIG_KMEMCHECK
#define memcpy(t, f, n) \
(__builtin_constant_p((n)) \
? __constant_memcpy((t), (f), (n)) \
: __memcpy((t), (f), (n)))
+#else
+/*
+ * kmemcheck becomes very happy if we use the REP instructions unconditionally,
+ * because it means that we know both memory operands in advance.
+ */
+#define memcpy(t, f, n) __memcpy((t), (f), (n))
+#endif
#endif
function. */
#define __HAVE_ARCH_MEMCPY 1
+#ifndef CONFIG_KMEMCHECK
#if (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) || __GNUC__ > 4
extern void *memcpy(void *to, const void *from, size_t len);
#else
__ret; \
})
#endif
+#else
+/*
+ * kmemcheck becomes very happy if we use the REP instructions unconditionally,
+ * because it means that we know both memory operands in advance.
+ */
+#define memcpy(dst, src, len) __inline_memcpy((dst), (src), (len))
+#endif
#define __HAVE_ARCH_MEMSET
void *memset(void *s, int c, size_t n);
/* thread information allocation */
#ifdef CONFIG_DEBUG_STACK_USAGE
-#define THREAD_FLAGS (GFP_KERNEL | __GFP_ZERO)
+#define THREAD_FLAGS (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO)
#else
-#define THREAD_FLAGS GFP_KERNEL
+#define THREAD_FLAGS (GFP_KERNEL | __GFP_NOTRACK)
#endif
#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
+#ifdef CONFIG_KMEMCHECK
+/* kmemcheck doesn't handle MMX/SSE/SSE2 instructions */
+# include <asm-generic/xor.h>
+#else
#ifdef CONFIG_X86_32
# include "xor_32.h"
#else
# include "xor_64.h"
#endif
+#endif
*/
if (c->x86 == 6 && c->x86_model < 15)
clear_cpu_cap(c, X86_FEATURE_PAT);
+
+#ifdef CONFIG_KMEMCHECK
+ /*
+ * P4s have a "fast strings" feature which causes single-
+ * stepping REP instructions to only generate a #DB on
+ * cache-line boundaries.
+ *
+ * Ingo Molnar reported a Pentium D (model 6) and a Xeon
+ * (model 2) with the same problem.
+ */
+ if (c->x86 == 15) {
+ u64 misc_enable;
+
+ rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable);
+
+ if (misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING) {
+ printk(KERN_INFO "kmemcheck: Disabling fast string operations\n");
+
+ misc_enable &= ~MSR_IA32_MISC_ENABLE_FAST_STRING;
+ wrmsrl(MSR_IA32_MISC_ENABLE, misc_enable);
+ }
+ }
+#endif
}
#ifdef CONFIG_X86_32
task_xstate_cachep =
kmem_cache_create("task_xstate", xstate_size,
__alignof__(union thread_xstate),
- SLAB_PANIC, NULL);
+ SLAB_PANIC | SLAB_NOTRACK, NULL);
}
/*
}
EXPORT_SYMBOL_GPL(save_stack_trace);
+void save_stack_trace_bp(struct stack_trace *trace, unsigned long bp)
+{
+ dump_trace(current, NULL, NULL, bp, &save_stack_ops, trace);
+ if (trace->nr_entries < trace->max_entries)
+ trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace);
#include <linux/edac.h>
#endif
+#include <asm/kmemcheck.h>
#include <asm/stacktrace.h>
#include <asm/processor.h>
#include <asm/debugreg.h>
get_debugreg(condition, 6);
+ /* Catch kmemcheck conditions first of all! */
+ if (condition & DR_STEP && kmemcheck_trap(regs))
+ return;
+
/*
* The processor cleared BTF, so don't mark that we need it set.
*/
obj-$(CONFIG_HIGHMEM) += highmem_32.o
+obj-$(CONFIG_KMEMCHECK) += kmemcheck/
+
obj-$(CONFIG_MMIOTRACE) += mmiotrace.o
mmiotrace-y := kmmio.o pf_in.o mmio-mod.o
obj-$(CONFIG_MMIOTRACE_TEST) += testmmiotrace.o
#include <asm/traps.h> /* dotraplinkage, ... */
#include <asm/pgalloc.h> /* pgd_*(), ... */
+#include <asm/kmemcheck.h> /* kmemcheck_*(), ... */
/*
* Page fault error code bits:
/* Get the faulting address: */
address = read_cr2();
+ /*
+ * Detect and handle instructions that would cause a page fault for
+ * both a tracked kernel page and a userspace page.
+ */
+ if (kmemcheck_active(regs))
+ kmemcheck_hide(regs);
+
if (unlikely(kmmio_fault(regs, address)))
return;
* protection error (error_code & 9) == 0.
*/
if (unlikely(fault_in_kernel_space(address))) {
- if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) &&
- vmalloc_fault(address) >= 0)
- return;
+ if (!(error_code & (PF_RSVD | PF_USER | PF_PROT))) {
+ if (vmalloc_fault(address) >= 0)
+ return;
+
+ if (kmemcheck_fault(regs, address, error_code))
+ return;
+ }
/* Can handle a stale RO->RW TLB: */
if (spurious_fault(error_code, address))
if (!after_bootmem)
init_gbpages();
-#ifdef CONFIG_DEBUG_PAGEALLOC
+#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
/*
* For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
* This will simplify cpa(), which otherwise needs to support splitting
pte_t *page_table = NULL;
if (after_bootmem) {
-#ifdef CONFIG_DEBUG_PAGEALLOC
+#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
#endif
if (!page_table)
void *ptr;
if (after_bootmem)
- ptr = (void *) get_zeroed_page(GFP_ATOMIC);
+ ptr = (void *) get_zeroed_page(GFP_ATOMIC | __GFP_NOTRACK);
else
ptr = alloc_bootmem_pages(PAGE_SIZE);
void *adr;
if (after_bootmem) {
- adr = (void *)get_zeroed_page(GFP_ATOMIC);
+ adr = (void *)get_zeroed_page(GFP_ATOMIC | __GFP_NOTRACK);
*phys = __pa(adr);
return adr;
--- /dev/null
+obj-y := error.o kmemcheck.o opcode.o pte.o selftest.o shadow.o
--- /dev/null
+#include <linux/interrupt.h>
+#include <linux/kdebug.h>
+#include <linux/kmemcheck.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/stacktrace.h>
+#include <linux/string.h>
+
+#include "error.h"
+#include "shadow.h"
+
+enum kmemcheck_error_type {
+ KMEMCHECK_ERROR_INVALID_ACCESS,
+ KMEMCHECK_ERROR_BUG,
+};
+
+#define SHADOW_COPY_SIZE (1 << CONFIG_KMEMCHECK_SHADOW_COPY_SHIFT)
+
+struct kmemcheck_error {
+ enum kmemcheck_error_type type;
+
+ union {
+ /* KMEMCHECK_ERROR_INVALID_ACCESS */
+ struct {
+ /* Kind of access that caused the error */
+ enum kmemcheck_shadow state;
+ /* Address and size of the erroneous read */
+ unsigned long address;
+ unsigned int size;
+ };
+ };
+
+ struct pt_regs regs;
+ struct stack_trace trace;
+ unsigned long trace_entries[32];
+
+ /* We compress it to a char. */
+ unsigned char shadow_copy[SHADOW_COPY_SIZE];
+ unsigned char memory_copy[SHADOW_COPY_SIZE];
+};
+
+/*
+ * Create a ring queue of errors to output. We can't call printk() directly
+ * from the kmemcheck traps, since this may call the console drivers and
+ * result in a recursive fault.
+ */
+static struct kmemcheck_error error_fifo[CONFIG_KMEMCHECK_QUEUE_SIZE];
+static unsigned int error_count;
+static unsigned int error_rd;
+static unsigned int error_wr;
+static unsigned int error_missed_count;
+
+static struct kmemcheck_error *error_next_wr(void)
+{
+ struct kmemcheck_error *e;
+
+ if (error_count == ARRAY_SIZE(error_fifo)) {
+ ++error_missed_count;
+ return NULL;
+ }
+
+ e = &error_fifo[error_wr];
+ if (++error_wr == ARRAY_SIZE(error_fifo))
+ error_wr = 0;
+ ++error_count;
+ return e;
+}
+
+static struct kmemcheck_error *error_next_rd(void)
+{
+ struct kmemcheck_error *e;
+
+ if (error_count == 0)
+ return NULL;
+
+ e = &error_fifo[error_rd];
+ if (++error_rd == ARRAY_SIZE(error_fifo))
+ error_rd = 0;
+ --error_count;
+ return e;
+}
+
+void kmemcheck_error_recall(void)
+{
+ static const char *desc[] = {
+ [KMEMCHECK_SHADOW_UNALLOCATED] = "unallocated",
+ [KMEMCHECK_SHADOW_UNINITIALIZED] = "uninitialized",
+ [KMEMCHECK_SHADOW_INITIALIZED] = "initialized",
+ [KMEMCHECK_SHADOW_FREED] = "freed",
+ };
+
+ static const char short_desc[] = {
+ [KMEMCHECK_SHADOW_UNALLOCATED] = 'a',
+ [KMEMCHECK_SHADOW_UNINITIALIZED] = 'u',
+ [KMEMCHECK_SHADOW_INITIALIZED] = 'i',
+ [KMEMCHECK_SHADOW_FREED] = 'f',
+ };
+
+ struct kmemcheck_error *e;
+ unsigned int i;
+
+ e = error_next_rd();
+ if (!e)
+ return;
+
+ switch (e->type) {
+ case KMEMCHECK_ERROR_INVALID_ACCESS:
+ printk(KERN_ERR "WARNING: kmemcheck: Caught %d-bit read "
+ "from %s memory (%p)\n",
+ 8 * e->size, e->state < ARRAY_SIZE(desc) ?
+ desc[e->state] : "(invalid shadow state)",
+ (void *) e->address);
+
+ printk(KERN_INFO);
+ for (i = 0; i < SHADOW_COPY_SIZE; ++i)
+ printk("%02x", e->memory_copy[i]);
+ printk("\n");
+
+ printk(KERN_INFO);
+ for (i = 0; i < SHADOW_COPY_SIZE; ++i) {
+ if (e->shadow_copy[i] < ARRAY_SIZE(short_desc))
+ printk(" %c", short_desc[e->shadow_copy[i]]);
+ else
+ printk(" ?");
+ }
+ printk("\n");
+ printk(KERN_INFO "%*c\n", 2 + 2
+ * (int) (e->address & (SHADOW_COPY_SIZE - 1)), '^');
+ break;
+ case KMEMCHECK_ERROR_BUG:
+ printk(KERN_EMERG "ERROR: kmemcheck: Fatal error\n");
+ break;
+ }
+
+ __show_regs(&e->regs, 1);
+ print_stack_trace(&e->trace, 0);
+}
+
+static void do_wakeup(unsigned long data)
+{
+ while (error_count > 0)
+ kmemcheck_error_recall();
+
+ if (error_missed_count > 0) {
+ printk(KERN_WARNING "kmemcheck: Lost %d error reports because "
+ "the queue was too small\n", error_missed_count);
+ error_missed_count = 0;
+ }
+}
+
+static DECLARE_TASKLET(kmemcheck_tasklet, &do_wakeup, 0);
+
+/*
+ * Save the context of an error report.
+ */
+void kmemcheck_error_save(enum kmemcheck_shadow state,
+ unsigned long address, unsigned int size, struct pt_regs *regs)
+{
+ static unsigned long prev_ip;
+
+ struct kmemcheck_error *e;
+ void *shadow_copy;
+ void *memory_copy;
+
+ /* Don't report several adjacent errors from the same EIP. */
+ if (regs->ip == prev_ip)
+ return;
+ prev_ip = regs->ip;
+
+ e = error_next_wr();
+ if (!e)
+ return;
+
+ e->type = KMEMCHECK_ERROR_INVALID_ACCESS;
+
+ e->state = state;
+ e->address = address;
+ e->size = size;
+
+ /* Save regs */
+ memcpy(&e->regs, regs, sizeof(*regs));
+
+ /* Save stack trace */
+ e->trace.nr_entries = 0;
+ e->trace.entries = e->trace_entries;
+ e->trace.max_entries = ARRAY_SIZE(e->trace_entries);
+ e->trace.skip = 0;
+ save_stack_trace_bp(&e->trace, regs->bp);
+
+ /* Round address down to nearest 16 bytes */
+ shadow_copy = kmemcheck_shadow_lookup(address
+ & ~(SHADOW_COPY_SIZE - 1));
+ BUG_ON(!shadow_copy);
+
+ memcpy(e->shadow_copy, shadow_copy, SHADOW_COPY_SIZE);
+
+ kmemcheck_show_addr(address);
+ memory_copy = (void *) (address & ~(SHADOW_COPY_SIZE - 1));
+ memcpy(e->memory_copy, memory_copy, SHADOW_COPY_SIZE);
+ kmemcheck_hide_addr(address);
+
+ tasklet_hi_schedule_first(&kmemcheck_tasklet);
+}
+
+/*
+ * Save the context of a kmemcheck bug.
+ */
+void kmemcheck_error_save_bug(struct pt_regs *regs)
+{
+ struct kmemcheck_error *e;
+
+ e = error_next_wr();
+ if (!e)
+ return;
+
+ e->type = KMEMCHECK_ERROR_BUG;
+
+ memcpy(&e->regs, regs, sizeof(*regs));
+
+ e->trace.nr_entries = 0;
+ e->trace.entries = e->trace_entries;
+ e->trace.max_entries = ARRAY_SIZE(e->trace_entries);
+ e->trace.skip = 1;
+ save_stack_trace(&e->trace);
+
+ tasklet_hi_schedule_first(&kmemcheck_tasklet);
+}
--- /dev/null
+#ifndef ARCH__X86__MM__KMEMCHECK__ERROR_H
+#define ARCH__X86__MM__KMEMCHECK__ERROR_H
+
+#include <linux/ptrace.h>
+
+#include "shadow.h"
+
+void kmemcheck_error_save(enum kmemcheck_shadow state,
+ unsigned long address, unsigned int size, struct pt_regs *regs);
+
+void kmemcheck_error_save_bug(struct pt_regs *regs);
+
+void kmemcheck_error_recall(void);
+
+#endif
--- /dev/null
+/**
+ * kmemcheck - a heavyweight memory checker for the linux kernel
+ * Copyright (C) 2007, 2008 Vegard Nossum <vegardno@ifi.uio.no>
+ * (With a lot of help from Ingo Molnar and Pekka Enberg.)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2) as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kallsyms.h>
+#include <linux/kernel.h>
+#include <linux/kmemcheck.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/page-flags.h>
+#include <linux/percpu.h>
+#include <linux/ptrace.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+#include <asm/cacheflush.h>
+#include <asm/kmemcheck.h>
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+
+#include "error.h"
+#include "opcode.h"
+#include "pte.h"
+#include "selftest.h"
+#include "shadow.h"
+
+
+#ifdef CONFIG_KMEMCHECK_DISABLED_BY_DEFAULT
+# define KMEMCHECK_ENABLED 0
+#endif
+
+#ifdef CONFIG_KMEMCHECK_ENABLED_BY_DEFAULT
+# define KMEMCHECK_ENABLED 1
+#endif
+
+#ifdef CONFIG_KMEMCHECK_ONESHOT_BY_DEFAULT
+# define KMEMCHECK_ENABLED 2
+#endif
+
+int kmemcheck_enabled = KMEMCHECK_ENABLED;
+
+int __init kmemcheck_init(void)
+{
+#ifdef CONFIG_SMP
+ /*
+ * Limit SMP to use a single CPU. We rely on the fact that this code
+ * runs before SMP is set up.
+ */
+ if (setup_max_cpus > 1) {
+ printk(KERN_INFO
+ "kmemcheck: Limiting number of CPUs to 1.\n");
+ setup_max_cpus = 1;
+ }
+#endif
+
+ if (!kmemcheck_selftest()) {
+ printk(KERN_INFO "kmemcheck: self-tests failed; disabling\n");
+ kmemcheck_enabled = 0;
+ return -EINVAL;
+ }
+
+ printk(KERN_INFO "kmemcheck: Initialized\n");
+ return 0;
+}
+
+early_initcall(kmemcheck_init);
+
+/*
+ * We need to parse the kmemcheck= option before any memory is allocated.
+ */
+static int __init param_kmemcheck(char *str)
+{
+ if (!str)
+ return -EINVAL;
+
+ sscanf(str, "%d", &kmemcheck_enabled);
+ return 0;
+}
+
+early_param("kmemcheck", param_kmemcheck);
+
+int kmemcheck_show_addr(unsigned long address)
+{
+ pte_t *pte;
+
+ pte = kmemcheck_pte_lookup(address);
+ if (!pte)
+ return 0;
+
+ set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT));
+ __flush_tlb_one(address);
+ return 1;
+}
+
+int kmemcheck_hide_addr(unsigned long address)
+{
+ pte_t *pte;
+
+ pte = kmemcheck_pte_lookup(address);
+ if (!pte)
+ return 0;
+
+ set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT));
+ __flush_tlb_one(address);
+ return 1;
+}
+
+struct kmemcheck_context {
+ bool busy;
+ int balance;
+
+ /*
+ * There can be at most two memory operands to an instruction, but
+ * each address can cross a page boundary -- so we may need up to
+ * four addresses that must be hidden/revealed for each fault.
+ */
+ unsigned long addr[4];
+ unsigned long n_addrs;
+ unsigned long flags;
+
+ /* Data size of the instruction that caused a fault. */
+ unsigned int size;
+};
+
+static DEFINE_PER_CPU(struct kmemcheck_context, kmemcheck_context);
+
+bool kmemcheck_active(struct pt_regs *regs)
+{
+ struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context);
+
+ return data->balance > 0;
+}
+
+/* Save an address that needs to be shown/hidden */
+static void kmemcheck_save_addr(unsigned long addr)
+{
+ struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context);
+
+ BUG_ON(data->n_addrs >= ARRAY_SIZE(data->addr));
+ data->addr[data->n_addrs++] = addr;
+}
+
+static unsigned int kmemcheck_show_all(void)
+{
+ struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context);
+ unsigned int i;
+ unsigned int n;
+
+ n = 0;
+ for (i = 0; i < data->n_addrs; ++i)
+ n += kmemcheck_show_addr(data->addr[i]);
+
+ return n;
+}
+
+static unsigned int kmemcheck_hide_all(void)
+{
+ struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context);
+ unsigned int i;
+ unsigned int n;
+
+ n = 0;
+ for (i = 0; i < data->n_addrs; ++i)
+ n += kmemcheck_hide_addr(data->addr[i]);
+
+ return n;
+}
+
+/*
+ * Called from the #PF handler.
+ */
+void kmemcheck_show(struct pt_regs *regs)
+{
+ struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context);
+
+ BUG_ON(!irqs_disabled());
+
+ if (unlikely(data->balance != 0)) {
+ kmemcheck_show_all();
+ kmemcheck_error_save_bug(regs);
+ data->balance = 0;
+ return;
+ }
+
+ /*
+ * None of the addresses actually belonged to kmemcheck. Note that
+ * this is not an error.
+ */
+ if (kmemcheck_show_all() == 0)
+ return;
+
+ ++data->balance;
+
+ /*
+ * The IF needs to be cleared as well, so that the faulting
+ * instruction can run "uninterrupted". Otherwise, we might take
+ * an interrupt and start executing that before we've had a chance
+ * to hide the page again.
+ *
+ * NOTE: In the rare case of multiple faults, we must not override
+ * the original flags:
+ */
+ if (!(regs->flags & X86_EFLAGS_TF))
+ data->flags = regs->flags;
+
+ regs->flags |= X86_EFLAGS_TF;
+ regs->flags &= ~X86_EFLAGS_IF;
+}
+
+/*
+ * Called from the #DB handler.
+ */
+void kmemcheck_hide(struct pt_regs *regs)
+{
+ struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context);
+ int n;
+
+ BUG_ON(!irqs_disabled());
+
+ if (data->balance == 0)
+ return;
+
+ if (unlikely(data->balance != 1)) {
+ kmemcheck_show_all();
+ kmemcheck_error_save_bug(regs);
+ data->n_addrs = 0;
+ data->balance = 0;
+
+ if (!(data->flags & X86_EFLAGS_TF))
+ regs->flags &= ~X86_EFLAGS_TF;
+ if (data->flags & X86_EFLAGS_IF)
+ regs->flags |= X86_EFLAGS_IF;
+ return;
+ }
+
+ if (kmemcheck_enabled)
+ n = kmemcheck_hide_all();
+ else
+ n = kmemcheck_show_all();
+
+ if (n == 0)
+ return;
+
+ --data->balance;
+
+ data->n_addrs = 0;
+
+ if (!(data->flags & X86_EFLAGS_TF))
+ regs->flags &= ~X86_EFLAGS_TF;
+ if (data->flags & X86_EFLAGS_IF)
+ regs->flags |= X86_EFLAGS_IF;
+}
+
+void kmemcheck_show_pages(struct page *p, unsigned int n)
+{
+ unsigned int i;
+
+ for (i = 0; i < n; ++i) {
+ unsigned long address;
+ pte_t *pte;
+ unsigned int level;
+
+ address = (unsigned long) page_address(&p[i]);
+ pte = lookup_address(address, &level);
+ BUG_ON(!pte);
+ BUG_ON(level != PG_LEVEL_4K);
+
+ set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT));
+ set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_HIDDEN));
+ __flush_tlb_one(address);
+ }
+}
+
+bool kmemcheck_page_is_tracked(struct page *p)
+{
+ /* This will also check the "hidden" flag of the PTE. */
+ return kmemcheck_pte_lookup((unsigned long) page_address(p));
+}
+
+void kmemcheck_hide_pages(struct page *p, unsigned int n)
+{
+ unsigned int i;
+
+ for (i = 0; i < n; ++i) {
+ unsigned long address;
+ pte_t *pte;
+ unsigned int level;
+
+ address = (unsigned long) page_address(&p[i]);
+ pte = lookup_address(address, &level);
+ BUG_ON(!pte);
+ BUG_ON(level != PG_LEVEL_4K);
+
+ set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT));
+ set_pte(pte, __pte(pte_val(*pte) | _PAGE_HIDDEN));
+ __flush_tlb_one(address);
+ }
+}
+
+/* Access may NOT cross page boundary */
+static void kmemcheck_read_strict(struct pt_regs *regs,
+ unsigned long addr, unsigned int size)
+{
+ void *shadow;
+ enum kmemcheck_shadow status;
+
+ shadow = kmemcheck_shadow_lookup(addr);
+ if (!shadow)
+ return;
+
+ kmemcheck_save_addr(addr);
+ status = kmemcheck_shadow_test(shadow, size);
+ if (status == KMEMCHECK_SHADOW_INITIALIZED)
+ return;
+
+ if (kmemcheck_enabled)
+ kmemcheck_error_save(status, addr, size, regs);
+
+ if (kmemcheck_enabled == 2)
+ kmemcheck_enabled = 0;
+
+ /* Don't warn about it again. */
+ kmemcheck_shadow_set(shadow, size);
+}
+
+/* Access may cross page boundary */
+static void kmemcheck_read(struct pt_regs *regs,
+ unsigned long addr, unsigned int size)
+{
+ unsigned long page = addr & PAGE_MASK;
+ unsigned long next_addr = addr + size - 1;
+ unsigned long next_page = next_addr & PAGE_MASK;
+
+ if (likely(page == next_page)) {
+ kmemcheck_read_strict(regs, addr, size);
+ return;
+ }
+
+ /*
+ * What we do is basically to split the access across the
+ * two pages and handle each part separately. Yes, this means
+ * that we may now see reads that are 3 + 5 bytes, for
+ * example (and if both are uninitialized, there will be two
+ * reports), but it makes the code a lot simpler.
+ */
+ kmemcheck_read_strict(regs, addr, next_page - addr);
+ kmemcheck_read_strict(regs, next_page, next_addr - next_page);
+}
+
+static void kmemcheck_write_strict(struct pt_regs *regs,
+ unsigned long addr, unsigned int size)
+{
+ void *shadow;
+
+ shadow = kmemcheck_shadow_lookup(addr);
+ if (!shadow)
+ return;
+
+ kmemcheck_save_addr(addr);
+ kmemcheck_shadow_set(shadow, size);
+}
+
+static void kmemcheck_write(struct pt_regs *regs,
+ unsigned long addr, unsigned int size)
+{
+ unsigned long page = addr & PAGE_MASK;
+ unsigned long next_addr = addr + size - 1;
+ unsigned long next_page = next_addr & PAGE_MASK;
+
+ if (likely(page == next_page)) {
+ kmemcheck_write_strict(regs, addr, size);
+ return;
+ }
+
+ /* See comment in kmemcheck_read(). */
+ kmemcheck_write_strict(regs, addr, next_page - addr);
+ kmemcheck_write_strict(regs, next_page, next_addr - next_page);
+}
+
+/*
+ * Copying is hard. We have two addresses, each of which may be split across
+ * a page (and each page will have different shadow addresses).
+ */
+static void kmemcheck_copy(struct pt_regs *regs,
+ unsigned long src_addr, unsigned long dst_addr, unsigned int size)
+{
+ uint8_t shadow[8];
+ enum kmemcheck_shadow status;
+
+ unsigned long page;
+ unsigned long next_addr;
+ unsigned long next_page;
+
+ uint8_t *x;
+ unsigned int i;
+ unsigned int n;
+
+ BUG_ON(size > sizeof(shadow));
+
+ page = src_addr & PAGE_MASK;
+ next_addr = src_addr + size - 1;
+ next_page = next_addr & PAGE_MASK;
+
+ if (likely(page == next_page)) {
+ /* Same page */
+ x = kmemcheck_shadow_lookup(src_addr);
+ if (x) {
+ kmemcheck_save_addr(src_addr);
+ for (i = 0; i < size; ++i)
+ shadow[i] = x[i];
+ } else {
+ for (i = 0; i < size; ++i)
+ shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
+ }
+ } else {
+ n = next_page - src_addr;
+ BUG_ON(n > sizeof(shadow));
+
+ /* First page */
+ x = kmemcheck_shadow_lookup(src_addr);
+ if (x) {
+ kmemcheck_save_addr(src_addr);
+ for (i = 0; i < n; ++i)
+ shadow[i] = x[i];
+ } else {
+ /* Not tracked */
+ for (i = 0; i < n; ++i)
+ shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
+ }
+
+ /* Second page */
+ x = kmemcheck_shadow_lookup(next_page);
+ if (x) {
+ kmemcheck_save_addr(next_page);
+ for (i = n; i < size; ++i)
+ shadow[i] = x[i - n];
+ } else {
+ /* Not tracked */
+ for (i = n; i < size; ++i)
+ shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
+ }
+ }
+
+ page = dst_addr & PAGE_MASK;
+ next_addr = dst_addr + size - 1;
+ next_page = next_addr & PAGE_MASK;
+
+ if (likely(page == next_page)) {
+ /* Same page */
+ x = kmemcheck_shadow_lookup(dst_addr);
+ if (x) {
+ kmemcheck_save_addr(dst_addr);
+ for (i = 0; i < size; ++i) {
+ x[i] = shadow[i];
+ shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
+ }
+ }
+ } else {
+ n = next_page - dst_addr;
+ BUG_ON(n > sizeof(shadow));
+
+ /* First page */
+ x = kmemcheck_shadow_lookup(dst_addr);
+ if (x) {
+ kmemcheck_save_addr(dst_addr);
+ for (i = 0; i < n; ++i) {
+ x[i] = shadow[i];
+ shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
+ }
+ }
+
+ /* Second page */
+ x = kmemcheck_shadow_lookup(next_page);
+ if (x) {
+ kmemcheck_save_addr(next_page);
+ for (i = n; i < size; ++i) {
+ x[i - n] = shadow[i];
+ shadow[i] = KMEMCHECK_SHADOW_INITIALIZED;
+ }
+ }
+ }
+
+ status = kmemcheck_shadow_test(shadow, size);
+ if (status == KMEMCHECK_SHADOW_INITIALIZED)
+ return;
+
+ if (kmemcheck_enabled)
+ kmemcheck_error_save(status, src_addr, size, regs);
+
+ if (kmemcheck_enabled == 2)
+ kmemcheck_enabled = 0;
+}
+
+enum kmemcheck_method {
+ KMEMCHECK_READ,
+ KMEMCHECK_WRITE,
+};
+
+static void kmemcheck_access(struct pt_regs *regs,
+ unsigned long fallback_address, enum kmemcheck_method fallback_method)
+{
+ const uint8_t *insn;
+ const uint8_t *insn_primary;
+ unsigned int size;
+
+ struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context);
+
+ /* Recursive fault -- ouch. */
+ if (data->busy) {
+ kmemcheck_show_addr(fallback_address);
+ kmemcheck_error_save_bug(regs);
+ return;
+ }
+
+ data->busy = true;
+
+ insn = (const uint8_t *) regs->ip;
+ insn_primary = kmemcheck_opcode_get_primary(insn);
+
+ kmemcheck_opcode_decode(insn, &size);
+
+ switch (insn_primary[0]) {
+#ifdef CONFIG_KMEMCHECK_BITOPS_OK
+ /* AND, OR, XOR */
+ /*
+ * Unfortunately, these instructions have to be excluded from
+ * our regular checking since they access only some (and not
+ * all) bits. This clears out "bogus" bitfield-access warnings.
+ */
+ case 0x80:
+ case 0x81:
+ case 0x82:
+ case 0x83:
+ switch ((insn_primary[1] >> 3) & 7) {
+ /* OR */
+ case 1:
+ /* AND */
+ case 4:
+ /* XOR */
+ case 6:
+ kmemcheck_write(regs, fallback_address, size);
+ goto out;
+
+ /* ADD */
+ case 0:
+ /* ADC */
+ case 2:
+ /* SBB */
+ case 3:
+ /* SUB */
+ case 5:
+ /* CMP */
+ case 7:
+ break;
+ }
+ break;
+#endif
+
+ /* MOVS, MOVSB, MOVSW, MOVSD */
+ case 0xa4:
+ case 0xa5:
+ /*
+ * These instructions are special because they take two
+ * addresses, but we only get one page fault.
+ */
+ kmemcheck_copy(regs, regs->si, regs->di, size);
+ goto out;
+
+ /* CMPS, CMPSB, CMPSW, CMPSD */
+ case 0xa6:
+ case 0xa7:
+ kmemcheck_read(regs, regs->si, size);
+ kmemcheck_read(regs, regs->di, size);
+ goto out;
+ }
+
+ /*
+ * If the opcode isn't special in any way, we use the data from the
+ * page fault handler to determine the address and type of memory
+ * access.
+ */
+ switch (fallback_method) {
+ case KMEMCHECK_READ:
+ kmemcheck_read(regs, fallback_address, size);
+ goto out;
+ case KMEMCHECK_WRITE:
+ kmemcheck_write(regs, fallback_address, size);
+ goto out;
+ }
+
+out:
+ data->busy = false;
+}
+
+bool kmemcheck_fault(struct pt_regs *regs, unsigned long address,
+ unsigned long error_code)
+{
+ pte_t *pte;
+
+ /*
+ * XXX: Is it safe to assume that memory accesses from virtual 86
+ * mode or non-kernel code segments will _never_ access kernel
+ * memory (e.g. tracked pages)? For now, we need this to avoid
+ * invoking kmemcheck for PnP BIOS calls.
+ */
+ if (regs->flags & X86_VM_MASK)
+ return false;
+ if (regs->cs != __KERNEL_CS)
+ return false;
+
+ pte = kmemcheck_pte_lookup(address);
+ if (!pte)
+ return false;
+
+ if (error_code & 2)
+ kmemcheck_access(regs, address, KMEMCHECK_WRITE);
+ else
+ kmemcheck_access(regs, address, KMEMCHECK_READ);
+
+ kmemcheck_show(regs);
+ return true;
+}
+
+bool kmemcheck_trap(struct pt_regs *regs)
+{
+ if (!kmemcheck_active(regs))
+ return false;
+
+ /* We're done. */
+ kmemcheck_hide(regs);
+ return true;
+}
--- /dev/null
+#include <linux/types.h>
+
+#include "opcode.h"
+
+static bool opcode_is_prefix(uint8_t b)
+{
+ return
+ /* Group 1 */
+ b == 0xf0 || b == 0xf2 || b == 0xf3
+ /* Group 2 */
+ || b == 0x2e || b == 0x36 || b == 0x3e || b == 0x26
+ || b == 0x64 || b == 0x65 || b == 0x2e || b == 0x3e
+ /* Group 3 */
+ || b == 0x66
+ /* Group 4 */
+ || b == 0x67;
+}
+
+#ifdef CONFIG_X86_64
+static bool opcode_is_rex_prefix(uint8_t b)
+{
+ return (b & 0xf0) == 0x40;
+}
+#else
+static bool opcode_is_rex_prefix(uint8_t b)
+{
+ return false;
+}
+#endif
+
+#define REX_W (1 << 3)
+
+/*
+ * This is a VERY crude opcode decoder. We only need to find the size of the
+ * load/store that caused our #PF and this should work for all the opcodes
+ * that we care about. Moreover, the ones who invented this instruction set
+ * should be shot.
+ */
+void kmemcheck_opcode_decode(const uint8_t *op, unsigned int *size)
+{
+ /* Default operand size */
+ int operand_size_override = 4;
+
+ /* prefixes */
+ for (; opcode_is_prefix(*op); ++op) {
+ if (*op == 0x66)
+ operand_size_override = 2;
+ }
+
+ /* REX prefix */
+ if (opcode_is_rex_prefix(*op)) {
+ uint8_t rex = *op;
+
+ ++op;
+ if (rex & REX_W) {
+ switch (*op) {
+ case 0x63:
+ *size = 4;
+ return;
+ case 0x0f:
+ ++op;
+
+ switch (*op) {
+ case 0xb6:
+ case 0xbe:
+ *size = 1;
+ return;
+ case 0xb7:
+ case 0xbf:
+ *size = 2;
+ return;
+ }
+
+ break;
+ }
+
+ *size = 8;
+ return;
+ }
+ }
+
+ /* escape opcode */
+ if (*op == 0x0f) {
+ ++op;
+
+ /*
+ * This is move with zero-extend and sign-extend, respectively;
+ * we don't have to think about 0xb6/0xbe, because this is
+ * already handled in the conditional below.
+ */
+ if (*op == 0xb7 || *op == 0xbf)
+ operand_size_override = 2;
+ }
+
+ *size = (*op & 1) ? operand_size_override : 1;
+}
+
+const uint8_t *kmemcheck_opcode_get_primary(const uint8_t *op)
+{
+ /* skip prefixes */
+ while (opcode_is_prefix(*op))
+ ++op;
+ if (opcode_is_rex_prefix(*op))
+ ++op;
+ return op;
+}
--- /dev/null
+#ifndef ARCH__X86__MM__KMEMCHECK__OPCODE_H
+#define ARCH__X86__MM__KMEMCHECK__OPCODE_H
+
+#include <linux/types.h>
+
+void kmemcheck_opcode_decode(const uint8_t *op, unsigned int *size);
+const uint8_t *kmemcheck_opcode_get_primary(const uint8_t *op);
+
+#endif
--- /dev/null
+#include <linux/mm.h>
+
+#include <asm/pgtable.h>
+
+#include "pte.h"
+
+pte_t *kmemcheck_pte_lookup(unsigned long address)
+{
+ pte_t *pte;
+ unsigned int level;
+
+ pte = lookup_address(address, &level);
+ if (!pte)
+ return NULL;
+ if (level != PG_LEVEL_4K)
+ return NULL;
+ if (!pte_hidden(*pte))
+ return NULL;
+
+ return pte;
+}
+
--- /dev/null
+#ifndef ARCH__X86__MM__KMEMCHECK__PTE_H
+#define ARCH__X86__MM__KMEMCHECK__PTE_H
+
+#include <linux/mm.h>
+
+#include <asm/pgtable.h>
+
+pte_t *kmemcheck_pte_lookup(unsigned long address);
+
+#endif
--- /dev/null
+#include <linux/kernel.h>
+
+#include "opcode.h"
+#include "selftest.h"
+
+struct selftest_opcode {
+ unsigned int expected_size;
+ const uint8_t *insn;
+ const char *desc;
+};
+
+static const struct selftest_opcode selftest_opcodes[] = {
+ /* REP MOVS */
+ {1, "\xf3\xa4", "rep movsb <mem8>, <mem8>"},
+ {4, "\xf3\xa5", "rep movsl <mem32>, <mem32>"},
+
+ /* MOVZX / MOVZXD */
+ {1, "\x66\x0f\xb6\x51\xf8", "movzwq <mem8>, <reg16>"},
+ {1, "\x0f\xb6\x51\xf8", "movzwq <mem8>, <reg32>"},
+
+ /* MOVSX / MOVSXD */
+ {1, "\x66\x0f\xbe\x51\xf8", "movswq <mem8>, <reg16>"},
+ {1, "\x0f\xbe\x51\xf8", "movswq <mem8>, <reg32>"},
+
+#ifdef CONFIG_X86_64
+ /* MOVZX / MOVZXD */
+ {1, "\x49\x0f\xb6\x51\xf8", "movzbq <mem8>, <reg64>"},
+ {2, "\x49\x0f\xb7\x51\xf8", "movzbq <mem16>, <reg64>"},
+
+ /* MOVSX / MOVSXD */
+ {1, "\x49\x0f\xbe\x51\xf8", "movsbq <mem8>, <reg64>"},
+ {2, "\x49\x0f\xbf\x51\xf8", "movsbq <mem16>, <reg64>"},
+ {4, "\x49\x63\x51\xf8", "movslq <mem32>, <reg64>"},
+#endif
+};
+
+static bool selftest_opcode_one(const struct selftest_opcode *op)
+{
+ unsigned size;
+
+ kmemcheck_opcode_decode(op->insn, &size);
+
+ if (size == op->expected_size)
+ return true;
+
+ printk(KERN_WARNING "kmemcheck: opcode %s: expected size %d, got %d\n",
+ op->desc, op->expected_size, size);
+ return false;
+}
+
+static bool selftest_opcodes_all(void)
+{
+ bool pass = true;
+ unsigned int i;
+
+ for (i = 0; i < ARRAY_SIZE(selftest_opcodes); ++i)
+ pass = pass && selftest_opcode_one(&selftest_opcodes[i]);
+
+ return pass;
+}
+
+bool kmemcheck_selftest(void)
+{
+ bool pass = true;
+
+ pass = pass && selftest_opcodes_all();
+
+ return pass;
+}
--- /dev/null
+#ifndef ARCH_X86_MM_KMEMCHECK_SELFTEST_H
+#define ARCH_X86_MM_KMEMCHECK_SELFTEST_H
+
+bool kmemcheck_selftest(void);
+
+#endif
--- /dev/null
+#include <linux/kmemcheck.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+#include "pte.h"
+#include "shadow.h"
+
+/*
+ * Return the shadow address for the given address. Returns NULL if the
+ * address is not tracked.
+ *
+ * We need to be extremely careful not to follow any invalid pointers,
+ * because this function can be called for *any* possible address.
+ */
+void *kmemcheck_shadow_lookup(unsigned long address)
+{
+ pte_t *pte;
+ struct page *page;
+
+ if (!virt_addr_valid(address))
+ return NULL;
+
+ pte = kmemcheck_pte_lookup(address);
+ if (!pte)
+ return NULL;
+
+ page = virt_to_page(address);
+ if (!page->shadow)
+ return NULL;
+ return page->shadow + (address & (PAGE_SIZE - 1));
+}
+
+static void mark_shadow(void *address, unsigned int n,
+ enum kmemcheck_shadow status)
+{
+ unsigned long addr = (unsigned long) address;
+ unsigned long last_addr = addr + n - 1;
+ unsigned long page = addr & PAGE_MASK;
+ unsigned long last_page = last_addr & PAGE_MASK;
+ unsigned int first_n;
+ void *shadow;
+
+ /* If the memory range crosses a page boundary, stop there. */
+ if (page == last_page)
+ first_n = n;
+ else
+ first_n = page + PAGE_SIZE - addr;
+
+ shadow = kmemcheck_shadow_lookup(addr);
+ if (shadow)
+ memset(shadow, status, first_n);
+
+ addr += first_n;
+ n -= first_n;
+
+ /* Do full-page memset()s. */
+ while (n >= PAGE_SIZE) {
+ shadow = kmemcheck_shadow_lookup(addr);
+ if (shadow)
+ memset(shadow, status, PAGE_SIZE);
+
+ addr += PAGE_SIZE;
+ n -= PAGE_SIZE;
+ }
+
+ /* Do the remaining page, if any. */
+ if (n > 0) {
+ shadow = kmemcheck_shadow_lookup(addr);
+ if (shadow)
+ memset(shadow, status, n);
+ }
+}
+
+void kmemcheck_mark_unallocated(void *address, unsigned int n)
+{
+ mark_shadow(address, n, KMEMCHECK_SHADOW_UNALLOCATED);
+}
+
+void kmemcheck_mark_uninitialized(void *address, unsigned int n)
+{
+ mark_shadow(address, n, KMEMCHECK_SHADOW_UNINITIALIZED);
+}
+
+/*
+ * Fill the shadow memory of the given address such that the memory at that
+ * address is marked as being initialized.
+ */
+void kmemcheck_mark_initialized(void *address, unsigned int n)
+{
+ mark_shadow(address, n, KMEMCHECK_SHADOW_INITIALIZED);
+}
+EXPORT_SYMBOL_GPL(kmemcheck_mark_initialized);
+
+void kmemcheck_mark_freed(void *address, unsigned int n)
+{
+ mark_shadow(address, n, KMEMCHECK_SHADOW_FREED);
+}
+
+void kmemcheck_mark_unallocated_pages(struct page *p, unsigned int n)
+{
+ unsigned int i;
+
+ for (i = 0; i < n; ++i)
+ kmemcheck_mark_unallocated(page_address(&p[i]), PAGE_SIZE);
+}
+
+void kmemcheck_mark_uninitialized_pages(struct page *p, unsigned int n)
+{
+ unsigned int i;
+
+ for (i = 0; i < n; ++i)
+ kmemcheck_mark_uninitialized(page_address(&p[i]), PAGE_SIZE);
+}
+
+void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n)
+{
+ unsigned int i;
+
+ for (i = 0; i < n; ++i)
+ kmemcheck_mark_initialized(page_address(&p[i]), PAGE_SIZE);
+}
+
+enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size)
+{
+ uint8_t *x;
+ unsigned int i;
+
+ x = shadow;
+
+#ifdef CONFIG_KMEMCHECK_PARTIAL_OK
+ /*
+ * Make sure _some_ bytes are initialized. Gcc frequently generates
+ * code to access neighboring bytes.
+ */
+ for (i = 0; i < size; ++i) {
+ if (x[i] == KMEMCHECK_SHADOW_INITIALIZED)
+ return x[i];
+ }
+#else
+ /* All bytes must be initialized. */
+ for (i = 0; i < size; ++i) {
+ if (x[i] != KMEMCHECK_SHADOW_INITIALIZED)
+ return x[i];
+ }
+#endif
+
+ return x[0];
+}
+
+void kmemcheck_shadow_set(void *shadow, unsigned int size)
+{
+ uint8_t *x;
+ unsigned int i;
+
+ x = shadow;
+ for (i = 0; i < size; ++i)
+ x[i] = KMEMCHECK_SHADOW_INITIALIZED;
+}
--- /dev/null
+#ifndef ARCH__X86__MM__KMEMCHECK__SHADOW_H
+#define ARCH__X86__MM__KMEMCHECK__SHADOW_H
+
+enum kmemcheck_shadow {
+ KMEMCHECK_SHADOW_UNALLOCATED,
+ KMEMCHECK_SHADOW_UNINITIALIZED,
+ KMEMCHECK_SHADOW_INITIALIZED,
+ KMEMCHECK_SHADOW_FREED,
+};
+
+void *kmemcheck_shadow_lookup(unsigned long address);
+
+enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size);
+void kmemcheck_shadow_set(void *shadow, unsigned int size);
+
+#endif
if (!debug_pagealloc)
spin_unlock(&cpa_lock);
- base = alloc_pages(GFP_KERNEL, 0);
+ base = alloc_pages(GFP_KERNEL | __GFP_NOTRACK, 0);
if (!debug_pagealloc)
spin_lock(&cpa_lock);
if (!base)
#include <asm/tlb.h>
#include <asm/fixmap.h>
+#define PGALLOC_GFP GFP_KERNEL | __GFP_NOTRACK | __GFP_REPEAT | __GFP_ZERO
+
pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
{
- return (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
+ return (pte_t *)__get_free_page(PGALLOC_GFP);
}
pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
struct page *pte;
#ifdef CONFIG_HIGHPTE
- pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT|__GFP_ZERO, 0);
+ pte = alloc_pages(PGALLOC_GFP | __GFP_HIGHMEM, 0);
#else
- pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
+ pte = alloc_pages(PGALLOC_GFP, 0);
#endif
if (pte)
pgtable_page_ctor(pte);
bool failed = false;
for(i = 0; i < PREALLOCATED_PMDS; i++) {
- pmd_t *pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
+ pmd_t *pmd = (pmd_t *)__get_free_page(PGALLOC_GFP);
if (pmd == NULL)
failed = true;
pmds[i] = pmd;
pmd_t *pmds[PREALLOCATED_PMDS];
unsigned long flags;
- pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+ pgd = (pgd_t *)__get_free_page(PGALLOC_GFP);
if (pgd == NULL)
goto out;
void *b1, *b2;
struct xor_block_template *f, *fastest;
- b1 = (void *) __get_free_pages(GFP_KERNEL, 2);
+ /*
+ * Note: Since the memory is not actually used for _anything_ but to
+ * test the XOR speed, we don't really want kmemcheck to warn about
+ * reading uninitialized bytes here.
+ */
+ b1 = (void *) __get_free_pages(GFP_KERNEL | __GFP_NOTRACK, 2);
if (!b1) {
printk(KERN_WARNING "xor: Yikes! No memory available.\n");
return -ENOMEM;
#include <linux/errno.h>
#include <linux/kernel.h>
+#include <linux/kmemcheck.h>
#include <linux/string.h>
#include <asm/bug.h>
#include <asm/byteorder.h>
if (!kv)
return NULL;
+ kmemcheck_annotate_variable(kv->value.leaf.data[0]);
CSR1212_DESCRIPTOR_LEAF_SET_TYPE(kv, dtype);
CSR1212_DESCRIPTOR_LEAF_SET_SPECIFIER_ID(kv, specifier_id);
#include <linux/bitmap.h>
#include <linux/kernel.h>
+#include <linux/kmemcheck.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/delay.h>
struct hpsb_host *host;
nodeid_t nodeid;
unsigned int generation;
+
+ kmemcheck_bitfield_begin(flags);
unsigned int speed_unverified:1;
+ kmemcheck_bitfield_end(flags);
};
u8 *speed;
ci = kmalloc(sizeof(*ci), GFP_KERNEL);
+ kmemcheck_annotate_bitfield(ci, flags);
if (!ci)
return;
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kernel.h>
+#include <linux/kmemcheck.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/idr.h>
return ERR_PTR(-EINVAL);
c2dev = kmalloc(sizeof(struct c2port_device), GFP_KERNEL);
+ kmemcheck_annotate_bitfield(c2dev, flags);
if (unlikely(!c2dev))
return ERR_PTR(-ENOMEM);
*/
#include <linux/device.h>
+#include <linux/kmemcheck.h>
#define C2PORT_NAME_LEN 32
/* Main struct */
struct c2port_ops;
struct c2port_device {
+ kmemcheck_bitfield_begin(flags);
unsigned int access:1;
unsigned int flash_access:1;
+ kmemcheck_bitfield_end(flags);
int id;
char name[C2PORT_NAME_LEN];
extern struct kmem_cache *names_cachep;
-#define __getname() kmem_cache_alloc(names_cachep, GFP_KERNEL)
-#define __putname(name) kmem_cache_free(names_cachep, (void *)(name))
+#define __getname_gfp(gfp) kmem_cache_alloc(names_cachep, (gfp))
+#define __getname() __getname_gfp(GFP_KERNEL)
+#define __putname(name) kmem_cache_free(names_cachep, (void *)(name))
#ifndef CONFIG_AUDITSYSCALL
#define putname(name) __putname(name)
#else
#define __GFP_RECLAIMABLE ((__force gfp_t)0x80000u) /* Page is reclaimable */
#define __GFP_MOVABLE ((__force gfp_t)0x100000u) /* Page is movable */
-#define __GFP_BITS_SHIFT 21 /* Room for 21 __GFP_FOO bits */
+#ifdef CONFIG_KMEMCHECK
+#define __GFP_NOTRACK ((__force gfp_t)0x200000u) /* Don't track with kmemcheck */
+#else
+#define __GFP_NOTRACK ((__force gfp_t)0)
+#endif
+
+/*
+ * This may seem redundant, but it's a way of annotating false positives vs.
+ * allocations that simply cannot be supported (e.g. page tables).
+ */
+#define __GFP_NOTRACK_FALSE_POSITIVE (__GFP_NOTRACK)
+
+#define __GFP_BITS_SHIFT 22 /* Room for 22 __GFP_FOO bits */
#define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
/* This equals 0, but use constants in case they ever change */
__tasklet_hi_schedule(t);
}
+extern void __tasklet_hi_schedule_first(struct tasklet_struct *t);
+
+/*
+ * This version avoids touching any other tasklets. Needed for kmemcheck
+ * in order not to take any page faults while enqueueing this tasklet;
+ * consider VERY carefully whether you really need this or
+ * tasklet_hi_schedule()...
+ */
+static inline void tasklet_hi_schedule_first(struct tasklet_struct *t)
+{
+ if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
+ __tasklet_hi_schedule_first(t);
+}
+
static inline void tasklet_disable_nosync(struct tasklet_struct *t)
{
--- /dev/null
+#ifndef LINUX_KMEMCHECK_H
+#define LINUX_KMEMCHECK_H
+
+#include <linux/mm_types.h>
+#include <linux/types.h>
+
+#ifdef CONFIG_KMEMCHECK
+extern int kmemcheck_enabled;
+
+/* The slab-related functions. */
+void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node);
+void kmemcheck_free_shadow(struct page *page, int order);
+void kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object,
+ size_t size);
+void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size);
+
+void kmemcheck_pagealloc_alloc(struct page *p, unsigned int order,
+ gfp_t gfpflags);
+
+void kmemcheck_show_pages(struct page *p, unsigned int n);
+void kmemcheck_hide_pages(struct page *p, unsigned int n);
+
+bool kmemcheck_page_is_tracked(struct page *p);
+
+void kmemcheck_mark_unallocated(void *address, unsigned int n);
+void kmemcheck_mark_uninitialized(void *address, unsigned int n);
+void kmemcheck_mark_initialized(void *address, unsigned int n);
+void kmemcheck_mark_freed(void *address, unsigned int n);
+
+void kmemcheck_mark_unallocated_pages(struct page *p, unsigned int n);
+void kmemcheck_mark_uninitialized_pages(struct page *p, unsigned int n);
+void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n);
+
+int kmemcheck_show_addr(unsigned long address);
+int kmemcheck_hide_addr(unsigned long address);
+
+#else
+#define kmemcheck_enabled 0
+
+static inline void
+kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node)
+{
+}
+
+static inline void
+kmemcheck_free_shadow(struct page *page, int order)
+{
+}
+
+static inline void
+kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object,
+ size_t size)
+{
+}
+
+static inline void kmemcheck_slab_free(struct kmem_cache *s, void *object,
+ size_t size)
+{
+}
+
+static inline void kmemcheck_pagealloc_alloc(struct page *p,
+ unsigned int order, gfp_t gfpflags)
+{
+}
+
+static inline bool kmemcheck_page_is_tracked(struct page *p)
+{
+ return false;
+}
+
+static inline void kmemcheck_mark_unallocated(void *address, unsigned int n)
+{
+}
+
+static inline void kmemcheck_mark_uninitialized(void *address, unsigned int n)
+{
+}
+
+static inline void kmemcheck_mark_initialized(void *address, unsigned int n)
+{
+}
+
+static inline void kmemcheck_mark_freed(void *address, unsigned int n)
+{
+}
+
+static inline void kmemcheck_mark_unallocated_pages(struct page *p,
+ unsigned int n)
+{
+}
+
+static inline void kmemcheck_mark_uninitialized_pages(struct page *p,
+ unsigned int n)
+{
+}
+
+static inline void kmemcheck_mark_initialized_pages(struct page *p,
+ unsigned int n)
+{
+}
+
+#endif /* CONFIG_KMEMCHECK */
+
+/*
+ * Bitfield annotations
+ *
+ * How to use: If you have a struct using bitfields, for example
+ *
+ * struct a {
+ * int x:8, y:8;
+ * };
+ *
+ * then this should be rewritten as
+ *
+ * struct a {
+ * kmemcheck_bitfield_begin(flags);
+ * int x:8, y:8;
+ * kmemcheck_bitfield_end(flags);
+ * };
+ *
+ * Now the "flags_begin" and "flags_end" members may be used to refer to the
+ * beginning and end, respectively, of the bitfield (and things like
+ * &x.flags_begin is allowed). As soon as the struct is allocated, the bit-
+ * fields should be annotated:
+ *
+ * struct a *a = kmalloc(sizeof(struct a), GFP_KERNEL);
+ * kmemcheck_annotate_bitfield(a, flags);
+ *
+ * Note: We provide the same definitions for both kmemcheck and non-
+ * kmemcheck kernels. This makes it harder to introduce accidental errors. It
+ * is also allowed to pass NULL pointers to kmemcheck_annotate_bitfield().
+ */
+#define kmemcheck_bitfield_begin(name) \
+ int name##_begin[0];
+
+#define kmemcheck_bitfield_end(name) \
+ int name##_end[0];
+
+#define kmemcheck_annotate_bitfield(ptr, name) \
+ do if (ptr) { \
+ int _n = (long) &((ptr)->name##_end) \
+ - (long) &((ptr)->name##_begin); \
+ BUILD_BUG_ON(_n < 0); \
+ \
+ kmemcheck_mark_initialized(&((ptr)->name##_begin), _n); \
+ } while (0)
+
+#define kmemcheck_annotate_variable(var) \
+ do { \
+ kmemcheck_mark_initialized(&(var), sizeof(var)); \
+ } while (0) \
+
+#endif /* LINUX_KMEMCHECK_H */
#ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
unsigned long debug_flags; /* Use atomic bitops on this */
#endif
+
+#ifdef CONFIG_KMEMCHECK
+ /*
+ * kmemcheck wants to track the status of each byte in a page; this
+ * is a pointer to such a status block. NULL if not tracked.
+ */
+ void *shadow;
+#endif
};
/*
#ifndef _LINUX_RING_BUFFER_H
#define _LINUX_RING_BUFFER_H
+#include <linux/kmemcheck.h>
#include <linux/mm.h>
#include <linux/seq_file.h>
* Don't refer to this struct directly, use functions below.
*/
struct ring_buffer_event {
+ kmemcheck_bitfield_begin(bitfield);
u32 type_len:5, time_delta:27;
+ kmemcheck_bitfield_end(bitfield);
+
u32 array[];
};
#define _LINUX_SKBUFF_H
#include <linux/kernel.h>
+#include <linux/kmemcheck.h>
#include <linux/compiler.h>
#include <linux/time.h>
#include <linux/cache.h>
};
};
__u32 priority;
+ kmemcheck_bitfield_begin(flags1);
__u8 local_df:1,
cloned:1,
ip_summed:2,
ipvs_property:1,
peeked:1,
nf_trace:1;
+ kmemcheck_bitfield_end(flags1);
__be16 protocol;
void (*destructor)(struct sk_buff *skb);
__u16 tc_verd; /* traffic control verdict */
#endif
#endif
+
+ kmemcheck_bitfield_begin(flags2);
#ifdef CONFIG_IPV6_NDISC_NODETYPE
__u8 ndisc_nodetype:2;
#endif
__u8 do_not_encrypt:1;
__u8 requeue:1;
#endif
+ kmemcheck_bitfield_end(flags2);
+
/* 0/13/14 bit hole */
#ifdef CONFIG_NET_DMA
#define SLAB_NOLEAKTRACE 0x00800000UL /* Avoid kmemleak tracing */
+/* Don't track use of uninitialized memory */
+#ifdef CONFIG_KMEMCHECK
+# define SLAB_NOTRACK 0x01000000UL
+#else
+# define SLAB_NOTRACK 0x00000000UL
+#endif
+
/* The following flags affect the page allocator grouping pages by mobility */
#define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are reclaimable */
#define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
#include <linux/compiler.h>
#include <linux/kmemtrace.h>
+/*
+ * struct kmem_cache
+ *
+ * manages a cache.
+ */
+
+struct kmem_cache {
+/* 1) per-cpu data, touched during every alloc/free */
+ struct array_cache *array[NR_CPUS];
+/* 2) Cache tunables. Protected by cache_chain_mutex */
+ unsigned int batchcount;
+ unsigned int limit;
+ unsigned int shared;
+
+ unsigned int buffer_size;
+ u32 reciprocal_buffer_size;
+/* 3) touched by every alloc & free from the backend */
+
+ unsigned int flags; /* constant flags */
+ unsigned int num; /* # of objs per slab */
+
+/* 4) cache_grow/shrink */
+ /* order of pgs per slab (2^n) */
+ unsigned int gfporder;
+
+ /* force GFP flags, e.g. GFP_DMA */
+ gfp_t gfpflags;
+
+ size_t colour; /* cache colouring range */
+ unsigned int colour_off; /* colour offset */
+ struct kmem_cache *slabp_cache;
+ unsigned int slab_size;
+ unsigned int dflags; /* dynamic flags */
+
+ /* constructor func */
+ void (*ctor)(void *obj);
+
+/* 5) cache creation/removal */
+ const char *name;
+ struct list_head next;
+
+/* 6) statistics */
+#ifdef CONFIG_DEBUG_SLAB
+ unsigned long num_active;
+ unsigned long num_allocations;
+ unsigned long high_mark;
+ unsigned long grown;
+ unsigned long reaped;
+ unsigned long errors;
+ unsigned long max_freeable;
+ unsigned long node_allocs;
+ unsigned long node_frees;
+ unsigned long node_overflow;
+ atomic_t allochit;
+ atomic_t allocmiss;
+ atomic_t freehit;
+ atomic_t freemiss;
+
+ /*
+ * If debugging is enabled, then the allocator can add additional
+ * fields and/or padding to every object. buffer_size contains the total
+ * object size including these internal fields, the following two
+ * variables contain the offset to the user object and its size.
+ */
+ int obj_offset;
+ int obj_size;
+#endif /* CONFIG_DEBUG_SLAB */
+
+ /*
+ * We put nodelists[] at the end of kmem_cache, because we want to size
+ * this array to nr_node_ids slots instead of MAX_NUMNODES
+ * (see kmem_cache_init())
+ * We still use [MAX_NUMNODES] and not [1] or [0] because cache_cache
+ * is statically defined, so we reserve the max number of nodes.
+ */
+ struct kmem_list3 *nodelists[MAX_NUMNODES];
+ /*
+ * Do not add fields after nodelists[]
+ */
+};
+
/* Size description struct for general caches. */
struct cache_sizes {
size_t cs_size;
struct task_struct;
#ifdef CONFIG_STACKTRACE
+struct task_struct;
+
struct stack_trace {
unsigned int nr_entries, max_entries;
unsigned long *entries;
};
extern void save_stack_trace(struct stack_trace *trace);
+extern void save_stack_trace_bp(struct stack_trace *trace, unsigned long bp);
extern void save_stack_trace_tsk(struct task_struct *tsk,
struct stack_trace *trace);
#define _INET_SOCK_H
+#include <linux/kmemcheck.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/jhash.h>
__be32 loc_addr;
__be32 rmt_addr;
__be16 rmt_port;
- u16 snd_wscale : 4,
- rcv_wscale : 4,
+ kmemcheck_bitfield_begin(flags);
+ u16 snd_wscale : 4,
+ rcv_wscale : 4,
tstamp_ok : 1,
sack_ok : 1,
wscale_ok : 1,
ecn_ok : 1,
acked : 1,
no_srccheck: 1;
+ kmemcheck_bitfield_end(flags);
struct ip_options *opt;
};
static inline struct request_sock *inet_reqsk_alloc(struct request_sock_ops *ops)
{
struct request_sock *req = reqsk_alloc(ops);
+ struct inet_request_sock *ireq = inet_rsk(req);
- if (req != NULL)
- inet_rsk(req)->opt = NULL;
+ if (req != NULL) {
+ kmemcheck_annotate_bitfield(ireq, flags);
+ ireq->opt = NULL;
+ }
return req;
}
#define _INET_TIMEWAIT_SOCK_
+#include <linux/kmemcheck.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/timer.h>
__be32 tw_rcv_saddr;
__be16 tw_dport;
__u16 tw_num;
+ kmemcheck_bitfield_begin(flags);
/* And these are ours. */
__u8 tw_ipv6only:1,
tw_transparent:1;
- /* 15 bits hole, try to pack */
+ /* 14 bits hole, try to pack */
+ kmemcheck_bitfield_end(flags);
__u16 tw_ipv6_offset;
unsigned long tw_ttd;
struct inet_bind_bucket *tw_tb;
#define sk_hash __sk_common.skc_hash
#define sk_prot __sk_common.skc_prot
#define sk_net __sk_common.skc_net
+ kmemcheck_bitfield_begin(flags);
unsigned char sk_shutdown : 2,
sk_no_check : 2,
sk_userlocks : 4;
+ kmemcheck_bitfield_end(flags);
unsigned char sk_protocol;
unsigned short sk_type;
int sk_rcvbuf;
void __init mount_block_root(char *name, int flags)
{
- char *fs_names = __getname();
+ char *fs_names = __getname_gfp(GFP_KERNEL
+ | __GFP_NOTRACK_FALSE_POSITIVE);
char *p;
#ifdef CONFIG_BLOCK
char b[BDEVNAME_SIZE];
#include <linux/idr.h>
#include <linux/ftrace.h>
#include <linux/async.h>
+#include <linux/kmemcheck.h>
#include <linux/kmemtrace.h>
#include <trace/boot.h>
/* create a slab on which task_structs can be allocated */
task_struct_cachep =
kmem_cache_create("task_struct", sizeof(struct task_struct),
- ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL);
+ ARCH_MIN_TASKALIGN, SLAB_PANIC | SLAB_NOTRACK, NULL);
#endif
/* do the arch specific task caches init */
{
sighand_cachep = kmem_cache_create("sighand_cache",
sizeof(struct sighand_struct), 0,
- SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU,
- sighand_ctor);
+ SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU|
+ SLAB_NOTRACK, sighand_ctor);
signal_cachep = kmem_cache_create("signal_cache",
sizeof(struct signal_struct), 0,
- SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+ SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
files_cachep = kmem_cache_create("files_cache",
sizeof(struct files_struct), 0,
- SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+ SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
fs_cachep = kmem_cache_create("fs_cache",
sizeof(struct fs_struct), 0,
- SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+ SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
mm_cachep = kmem_cache_create("mm_struct",
sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN,
- SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+ SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC);
mmap_init();
}
{
struct sigpending *pending;
struct sigqueue *q;
+ int override_rlimit;
trace_sched_signal_send(sig, t);
make sure at least one signal gets delivered and don't
pass on the info struct. */
- q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
- (is_si_special(info) ||
- info->si_code >= 0)));
+ if (sig < SIGRTMIN)
+ override_rlimit = (is_si_special(info) || info->si_code >= 0);
+ else
+ override_rlimit = 0;
+
+ q = __sigqueue_alloc(t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
+ override_rlimit);
if (q) {
list_add_tail(&q->list, &pending->list);
switch ((unsigned long) info) {
EXPORT_SYMBOL(__tasklet_hi_schedule);
+void __tasklet_hi_schedule_first(struct tasklet_struct *t)
+{
+ BUG_ON(!irqs_disabled());
+
+ t->next = __get_cpu_var(tasklet_hi_vec).head;
+ __get_cpu_var(tasklet_hi_vec).head = t;
+ __raise_softirq_irqoff(HI_SOFTIRQ);
+}
+
+EXPORT_SYMBOL(__tasklet_hi_schedule_first);
+
static void tasklet_action(struct softirq_action *a)
{
struct tasklet_struct *list;
#include <linux/security.h>
#include <linux/ctype.h>
#include <linux/utsname.h>
+#include <linux/kmemcheck.h>
#include <linux/smp_lock.h>
#include <linux/fs.h>
#include <linux/init.h>
.proc_handler = &proc_dointvec,
},
#endif
+#ifdef CONFIG_KMEMCHECK
+ {
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "kmemcheck",
+ .data = &kmemcheck_enabled,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
+#endif
+
/*
* NOTE: do not add new entries to this table unless you have read
* Documentation/sysctl/ctl_unnumbered.txt
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/hardirq.h>
+#include <linux/kmemcheck.h>
#include <linux/module.h>
#include <linux/percpu.h>
#include <linux/mutex.h>
if (tail < BUF_PAGE_SIZE) {
/* Mark the rest of the page with padding */
event = __rb_page_index(tail_page, tail);
+ kmemcheck_annotate_bitfield(event, bitfield);
rb_event_set_padding(event);
}
return NULL;
event = __rb_page_index(tail_page, tail);
+ kmemcheck_annotate_bitfield(event, bitfield);
rb_update_event(event, type, length);
/* The passed in type is zero for DATA */
config DEBUG_SLAB
bool "Debug slab memory allocations"
- depends on DEBUG_KERNEL && SLAB
+ depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
help
Say Y here to have the kernel do limited verification on memory
allocation as well as poisoning memory on free to catch use of freed
config SLUB_DEBUG_ON
bool "SLUB debugging on by default"
- depends on SLUB && SLUB_DEBUG
+ depends on SLUB && SLUB_DEBUG && !KMEMCHECK
default n
help
Boot with debugging on by default. SLUB boots by default with
source "samples/Kconfig"
source "lib/Kconfig.kgdb"
+
+source "lib/Kconfig.kmemcheck"
--- /dev/null
+config HAVE_ARCH_KMEMCHECK
+ bool
+
+menuconfig KMEMCHECK
+ bool "kmemcheck: trap use of uninitialized memory"
+ depends on DEBUG_KERNEL
+ depends on !X86_USE_3DNOW
+ depends on SLUB || SLAB
+ depends on !CC_OPTIMIZE_FOR_SIZE
+ depends on !FUNCTION_TRACER
+ select FRAME_POINTER
+ select STACKTRACE
+ default n
+ help
+ This option enables tracing of dynamically allocated kernel memory
+ to see if memory is used before it has been given an initial value.
+ Be aware that this requires half of your memory for bookkeeping and
+ will insert extra code at *every* read and write to tracked memory
+ thus slow down the kernel code (but user code is unaffected).
+
+ The kernel may be started with kmemcheck=0 or kmemcheck=1 to disable
+ or enable kmemcheck at boot-time. If the kernel is started with
+ kmemcheck=0, the large memory and CPU overhead is not incurred.
+
+choice
+ prompt "kmemcheck: default mode at boot"
+ depends on KMEMCHECK
+ default KMEMCHECK_ONESHOT_BY_DEFAULT
+ help
+ This option controls the default behaviour of kmemcheck when the
+ kernel boots and no kmemcheck= parameter is given.
+
+config KMEMCHECK_DISABLED_BY_DEFAULT
+ bool "disabled"
+ depends on KMEMCHECK
+
+config KMEMCHECK_ENABLED_BY_DEFAULT
+ bool "enabled"
+ depends on KMEMCHECK
+
+config KMEMCHECK_ONESHOT_BY_DEFAULT
+ bool "one-shot"
+ depends on KMEMCHECK
+ help
+ In one-shot mode, only the first error detected is reported before
+ kmemcheck is disabled.
+
+endchoice
+
+config KMEMCHECK_QUEUE_SIZE
+ int "kmemcheck: error queue size"
+ depends on KMEMCHECK
+ default 64
+ help
+ Select the maximum number of errors to store in the queue. Since
+ errors can occur virtually anywhere and in any context, we need a
+ temporary storage area which is guarantueed not to generate any
+ other faults. The queue will be emptied as soon as a tasklet may
+ be scheduled. If the queue is full, new error reports will be
+ lost.
+
+config KMEMCHECK_SHADOW_COPY_SHIFT
+ int "kmemcheck: shadow copy size (5 => 32 bytes, 6 => 64 bytes)"
+ depends on KMEMCHECK
+ range 2 8
+ default 5
+ help
+ Select the number of shadow bytes to save along with each entry of
+ the queue. These bytes indicate what parts of an allocation are
+ initialized, uninitialized, etc. and will be displayed when an
+ error is detected to help the debugging of a particular problem.
+
+config KMEMCHECK_PARTIAL_OK
+ bool "kmemcheck: allow partially uninitialized memory"
+ depends on KMEMCHECK
+ default y
+ help
+ This option works around certain GCC optimizations that produce
+ 32-bit reads from 16-bit variables where the upper 16 bits are
+ thrown away afterwards. This may of course also hide some real
+ bugs.
+
+config KMEMCHECK_BITOPS_OK
+ bool "kmemcheck: allow bit-field manipulation"
+ depends on KMEMCHECK
+ default n
+ help
+ This option silences warnings that would be generated for bit-field
+ accesses where not all the bits are initialized at the same time.
+ This may also hide some real bugs.
+
bool "Debug page memory allocations"
depends on DEBUG_KERNEL && ARCH_SUPPORTS_DEBUG_PAGEALLOC
depends on !HIBERNATION || !PPC && !SPARC
+ depends on !KMEMCHECK
---help---
Unmap pages from the kernel linear mapping after free_pages().
This results in a large slowdown, but helps to find certain types
obj-$(CONFIG_PAGE_POISONING) += debug-pagealloc.o
obj-$(CONFIG_SLAB) += slab.o
obj-$(CONFIG_SLUB) += slub.o
+obj-$(CONFIG_KMEMCHECK) += kmemcheck.o
obj-$(CONFIG_FAILSLAB) += failslab.o
obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
obj-$(CONFIG_FS_XIP) += filemap_xip.o
--- /dev/null
+#include <linux/gfp.h>
+#include <linux/mm_types.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/kmemcheck.h>
+
+void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node)
+{
+ struct page *shadow;
+ int pages;
+ int i;
+
+ pages = 1 << order;
+
+ /*
+ * With kmemcheck enabled, we need to allocate a memory area for the
+ * shadow bits as well.
+ */
+ shadow = alloc_pages_node(node, flags | __GFP_NOTRACK, order);
+ if (!shadow) {
+ if (printk_ratelimit())
+ printk(KERN_ERR "kmemcheck: failed to allocate "
+ "shadow bitmap\n");
+ return;
+ }
+
+ for(i = 0; i < pages; ++i)
+ page[i].shadow = page_address(&shadow[i]);
+
+ /*
+ * Mark it as non-present for the MMU so that our accesses to
+ * this memory will trigger a page fault and let us analyze
+ * the memory accesses.
+ */
+ kmemcheck_hide_pages(page, pages);
+}
+
+void kmemcheck_free_shadow(struct page *page, int order)
+{
+ struct page *shadow;
+ int pages;
+ int i;
+
+ if (!kmemcheck_page_is_tracked(page))
+ return;
+
+ pages = 1 << order;
+
+ kmemcheck_show_pages(page, pages);
+
+ shadow = virt_to_page(page[0].shadow);
+
+ for(i = 0; i < pages; ++i)
+ page[i].shadow = NULL;
+
+ __free_pages(shadow, order);
+}
+
+void kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object,
+ size_t size)
+{
+ /*
+ * Has already been memset(), which initializes the shadow for us
+ * as well.
+ */
+ if (gfpflags & __GFP_ZERO)
+ return;
+
+ /* No need to initialize the shadow of a non-tracked slab. */
+ if (s->flags & SLAB_NOTRACK)
+ return;
+
+ if (!kmemcheck_enabled || gfpflags & __GFP_NOTRACK) {
+ /*
+ * Allow notracked objects to be allocated from
+ * tracked caches. Note however that these objects
+ * will still get page faults on access, they just
+ * won't ever be flagged as uninitialized. If page
+ * faults are not acceptable, the slab cache itself
+ * should be marked NOTRACK.
+ */
+ kmemcheck_mark_initialized(object, size);
+ } else if (!s->ctor) {
+ /*
+ * New objects should be marked uninitialized before
+ * they're returned to the called.
+ */
+ kmemcheck_mark_uninitialized(object, size);
+ }
+}
+
+void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size)
+{
+ /* TODO: RCU freeing is unsupported for now; hide false positives. */
+ if (!s->ctor && !(s->flags & SLAB_DESTROY_BY_RCU))
+ kmemcheck_mark_freed(object, size);
+}
+
+void kmemcheck_pagealloc_alloc(struct page *page, unsigned int order,
+ gfp_t gfpflags)
+{
+ int pages;
+
+ if (gfpflags & (__GFP_HIGHMEM | __GFP_NOTRACK))
+ return;
+
+ pages = 1 << order;
+
+ /*
+ * NOTE: We choose to track GFP_ZERO pages too; in fact, they
+ * can become uninitialized by copying uninitialized memory
+ * into them.
+ */
+
+ /* XXX: Can use zone->node for node? */
+ kmemcheck_alloc_shadow(page, order, gfpflags, -1);
+
+ if (gfpflags & __GFP_ZERO)
+ kmemcheck_mark_initialized_pages(page, pages);
+ else
+ kmemcheck_mark_uninitialized_pages(page, pages);
+}
#include <linux/bootmem.h>
#include <linux/compiler.h>
#include <linux/kernel.h>
+#include <linux/kmemcheck.h>
#include <linux/module.h>
#include <linux/suspend.h>
#include <linux/pagevec.h>
int i;
int bad = 0;
+ kmemcheck_free_shadow(page, order);
+
for (i = 0 ; i < (1 << order) ; ++i)
bad += free_pages_check(page + i);
if (bad)
struct per_cpu_pages *pcp;
unsigned long flags;
+ kmemcheck_free_shadow(page, 0);
+
if (PageAnon(page))
page->mapping = NULL;
if (free_pages_check(page))
VM_BUG_ON(PageCompound(page));
VM_BUG_ON(!page_count(page));
+
+#ifdef CONFIG_KMEMCHECK
+ /*
+ * Split shadow pages too, because free(page[0]) would
+ * otherwise free the whole shadow.
+ */
+ if (kmemcheck_page_is_tracked(page))
+ split_page(virt_to_page(page[0].shadow), order);
+#endif
+
for (i = 1; i < (1 << order); i++)
set_page_refcounted(page + i);
}
dump_stack();
show_mem();
}
+ return page;
got_pg:
+ if (kmemcheck_enabled)
+ kmemcheck_pagealloc_alloc(page, order, gfp_mask);
return page;
}
EXPORT_SYMBOL(__alloc_pages_internal);
#include <linux/rtmutex.h>
#include <linux/reciprocal_div.h>
#include <linux/debugobjects.h>
+#include <linux/kmemcheck.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
SLAB_STORE_USER | \
SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
- SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE)
+ SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK)
#else
# define CREATE_MASK (SLAB_HWCACHE_ALIGN | \
SLAB_CACHE_DMA | \
SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
- SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE)
+ SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK)
#endif
/*
MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
} while (0)
-/*
- * struct kmem_cache
- *
- * manages a cache.
- */
-
-struct kmem_cache {
-/* 1) per-cpu data, touched during every alloc/free */
- struct array_cache *array[NR_CPUS];
-/* 2) Cache tunables. Protected by cache_chain_mutex */
- unsigned int batchcount;
- unsigned int limit;
- unsigned int shared;
-
- unsigned int buffer_size;
- u32 reciprocal_buffer_size;
-/* 3) touched by every alloc & free from the backend */
-
- unsigned int flags; /* constant flags */
- unsigned int num; /* # of objs per slab */
-
-/* 4) cache_grow/shrink */
- /* order of pgs per slab (2^n) */
- unsigned int gfporder;
-
- /* force GFP flags, e.g. GFP_DMA */
- gfp_t gfpflags;
-
- size_t colour; /* cache colouring range */
- unsigned int colour_off; /* colour offset */
- struct kmem_cache *slabp_cache;
- unsigned int slab_size;
- unsigned int dflags; /* dynamic flags */
-
- /* constructor func */
- void (*ctor)(void *obj);
-
-/* 5) cache creation/removal */
- const char *name;
- struct list_head next;
-
-/* 6) statistics */
-#if STATS
- unsigned long num_active;
- unsigned long num_allocations;
- unsigned long high_mark;
- unsigned long grown;
- unsigned long reaped;
- unsigned long errors;
- unsigned long max_freeable;
- unsigned long node_allocs;
- unsigned long node_frees;
- unsigned long node_overflow;
- atomic_t allochit;
- atomic_t allocmiss;
- atomic_t freehit;
- atomic_t freemiss;
-#endif
-#if DEBUG
- /*
- * If debugging is enabled, then the allocator can add additional
- * fields and/or padding to every object. buffer_size contains the total
- * object size including these internal fields, the following two
- * variables contain the offset to the user object and its size.
- */
- int obj_offset;
- int obj_size;
-#endif
- /*
- * We put nodelists[] at the end of kmem_cache, because we want to size
- * this array to nr_node_ids slots instead of MAX_NUMNODES
- * (see kmem_cache_init())
- * We still use [MAX_NUMNODES] and not [1] or [0] because cache_cache
- * is statically defined, so we reserve the max number of nodes.
- */
- struct kmem_list3 *nodelists[MAX_NUMNODES];
- /*
- * Do not add fields after nodelists[]
- */
-};
-
#define CFLGS_OFF_SLAB (0x80000000UL)
#define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
flags |= __GFP_RECLAIMABLE;
- page = alloc_pages_node(nodeid, flags, cachep->gfporder);
+ page = alloc_pages_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
if (!page)
return NULL;
NR_SLAB_UNRECLAIMABLE, nr_pages);
for (i = 0; i < nr_pages; i++)
__SetPageSlab(page + i);
+
+ if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
+ kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid);
+
+ if (cachep->ctor)
+ kmemcheck_mark_uninitialized_pages(page, nr_pages);
+ else
+ kmemcheck_mark_unallocated_pages(page, nr_pages);
+ }
+
return page_address(page);
}
struct page *page = virt_to_page(addr);
const unsigned long nr_freed = i;
+ kmemcheck_free_shadow(page, cachep->gfporder);
+
if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
sub_zone_page_state(page_zone(page),
NR_SLAB_RECLAIMABLE, nr_freed);
kmemleak_alloc_recursive(ptr, obj_size(cachep), 1, cachep->flags,
flags);
+ if (likely(ptr))
+ kmemcheck_slab_alloc(cachep, flags, ptr, obj_size(cachep));
+
if (unlikely((flags & __GFP_ZERO) && ptr))
memset(ptr, 0, obj_size(cachep));
flags);
prefetchw(objp);
+ if (likely(objp))
+ kmemcheck_slab_alloc(cachep, flags, objp, obj_size(cachep));
+
if (unlikely((flags & __GFP_ZERO) && objp))
memset(objp, 0, obj_size(cachep));
kmemleak_free_recursive(objp, cachep->flags);
objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
+ kmemcheck_slab_free(cachep, objp, obj_size(cachep));
+
/*
* Skip calling cache_free_alien() when the platform is not numa.
* This will avoid cache misses that happen while accessing slabp (which
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/kmemtrace.h>
+#include <linux/kmemcheck.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
#include <linux/kmemleak.h>
SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE)
#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
- SLAB_CACHE_DMA)
+ SLAB_CACHE_DMA | SLAB_NOTRACK)
#ifndef ARCH_KMALLOC_MINALIGN
#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
{
int order = oo_order(oo);
+ flags |= __GFP_NOTRACK;
+
if (node == -1)
return alloc_pages(flags, order);
else
stat(get_cpu_slab(s, raw_smp_processor_id()), ORDER_FALLBACK);
}
+
+ if (kmemcheck_enabled
+ && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS)))
+ {
+ int pages = 1 << oo_order(oo);
+
+ kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
+
+ /*
+ * Objects from caches that have a constructor don't get
+ * cleared when they're allocated, so we need to do it here.
+ */
+ if (s->ctor)
+ kmemcheck_mark_uninitialized_pages(page, pages);
+ else
+ kmemcheck_mark_unallocated_pages(page, pages);
+ }
+
page->objects = oo_objects(oo);
mod_zone_page_state(page_zone(page),
(s->flags & SLAB_RECLAIM_ACCOUNT) ?
__ClearPageSlubDebug(page);
}
+ kmemcheck_free_shadow(page, compound_order(page));
+
mod_zone_page_state(page_zone(page),
(s->flags & SLAB_RECLAIM_ACCOUNT) ?
NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
if (unlikely((gfpflags & __GFP_ZERO) && object))
memset(object, 0, objsize);
+ kmemcheck_slab_alloc(s, gfpflags, object, c->objsize);
kmemleak_alloc_recursive(object, objsize, 1, s->flags, gfpflags);
+
return object;
}
kmemleak_free_recursive(x, s->flags);
local_irq_save(flags);
c = get_cpu_slab(s, smp_processor_id());
+ kmemcheck_slab_free(s, object, c->objsize);
debug_check_no_locks_freed(object, c->objsize);
if (!(s->flags & SLAB_DEBUG_OBJECTS))
debug_check_no_obj_freed(object, c->objsize);
if (!s || !text || !kmem_cache_open(s, flags, text,
realsize, ARCH_KMALLOC_MINALIGN,
- SLAB_CACHE_DMA|__SYSFS_ADD_DEFERRED, NULL)) {
+ SLAB_CACHE_DMA|SLAB_NOTRACK|__SYSFS_ADD_DEFERRED,
+ NULL)) {
kfree(s);
kfree(text);
goto unlock_out;
static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
{
- struct page *page = alloc_pages_node(node, flags | __GFP_COMP,
- get_order(size));
+ struct page *page;
+ flags |= __GFP_COMP | __GFP_NOTRACK;
+ page = alloc_pages_node(node, flags, get_order(size));
if (page)
return page_address(page);
else
*p++ = 'a';
if (s->flags & SLAB_DEBUG_FREE)
*p++ = 'F';
+ if (!(s->flags & SLAB_NOTRACK))
+ *p++ = 't';
if (p != name + 1)
*p++ = '-';
p += sprintf(p, "%07d", s->size);
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
+#include <linux/kmemcheck.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/in.h>
skb->data = data;
skb_reset_tail_pointer(skb);
skb->end = skb->tail + size;
+ kmemcheck_annotate_bitfield(skb, flags1);
+ kmemcheck_annotate_bitfield(skb, flags2);
/* make sure we initialize shinfo sequentially */
shinfo = skb_shinfo(skb);
atomic_set(&shinfo->dataref, 1);
struct sk_buff *child = skb + 1;
atomic_t *fclone_ref = (atomic_t *) (child + 1);
+ kmemcheck_annotate_bitfield(child, flags1);
+ kmemcheck_annotate_bitfield(child, flags2);
skb->fclone = SKB_FCLONE_ORIG;
atomic_set(fclone_ref, 1);
n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
if (!n)
return NULL;
+
+ kmemcheck_annotate_bitfield(n, flags1);
+ kmemcheck_annotate_bitfield(n, flags2);
n->fclone = SKB_FCLONE_UNAVAILABLE;
}
sk = kmalloc(prot->obj_size, priority);
if (sk != NULL) {
+ kmemcheck_annotate_bitfield(sk, flags);
+
if (security_sk_alloc(sk, family, priority))
goto out_free;
*/
#include <linux/kernel.h>
+#include <linux/kmemcheck.h>
#include <net/inet_hashtables.h>
#include <net/inet_timewait_sock.h>
#include <net/ip.h>
if (tw != NULL) {
const struct inet_sock *inet = inet_sk(sk);
+ kmemcheck_annotate_bitfield(tw, flags);
+
/* Give us an identity. */
tw->tw_daddr = inet->daddr;
tw->tw_rcv_saddr = inet->rcv_saddr;
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff