config PRINTK_TIME
bool "Show timing information on printks"
+ depends on PRINTK
help
Selecting this option causes timing information to be
included in printk output. This allows you to measure
operations. This is useful for identifying long delays
in kernel startup.
-
-config DEBUG_KERNEL
- bool "Kernel debugging"
+config ENABLE_MUST_CHECK
+ bool "Enable __must_check logic"
+ default y
help
- Say Y here if you are developing drivers or trying to debug and
- identify kernel problems.
+ Enable the __must_check logic in the kernel build. Disable this to
+ suppress the "warning: ignoring return value of 'foo', declared with
+ attribute warn_unused_result" messages.
config MAGIC_SYSRQ
bool "Magic SysRq key"
- depends on DEBUG_KERNEL && !UML
+ depends on !UML
help
If you say Y here, you will have some control over the system even
if the system crashes for example during kernel debugging (e.g., you
keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
unless you really know what this hack does.
-config LOG_BUF_SHIFT
- int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
- range 12 21
- default 17 if ARCH_S390
- default 16 if X86_NUMAQ || IA64
- default 15 if SMP
- default 14
- help
- Select kernel log buffer size as a power of 2.
- Defaults and Examples:
- 17 => 128 KB for S/390
- 16 => 64 KB for x86 NUMAQ or IA-64
- 15 => 32 KB for SMP
- 14 => 16 KB for uniprocessor
- 13 => 8 KB
- 12 => 4 KB
+config UNUSED_SYMBOLS
+ bool "Enable unused/obsolete exported symbols"
+ default y if X86
+ help
+ Unused but exported symbols make the kernel needlessly bigger. For
+ that reason most of these unused exports will soon be removed. This
+ option is provided temporarily to provide a transition period in case
+ some external kernel module needs one of these symbols anyway. If you
+ encounter such a case in your module, consider if you are actually
+ using the right API. (rationale: since nobody in the kernel is using
+ this in a module, there is a pretty good chance it's actually the
+ wrong interface to use). If you really need the symbol, please send a
+ mail to the linux kernel mailing list mentioning the symbol and why
+ you really need it, and what the merge plan to the mainline kernel for
+ your module is.
+
+config DEBUG_FS
+ bool "Debug Filesystem"
+ depends on SYSFS
+ help
+ debugfs is a virtual file system that kernel developers use to put
+ debugging files into. Enable this option to be able to read and
+ write to these files.
+
+ If unsure, say N.
+
+config HEADERS_CHECK
+ bool "Run 'make headers_check' when building vmlinux"
+ depends on !UML
+ help
+ This option will extract the user-visible kernel headers whenever
+ building the kernel, and will run basic sanity checks on them to
+ ensure that exported files do not attempt to include files which
+ were not exported, etc.
+
+ If you're making modifications to header files which are
+ relevant for userspace, say 'Y', and check the headers
+ exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
+ your build tree), to make sure they're suitable.
+
+config DEBUG_KERNEL
+ bool "Kernel debugging"
+ help
+ Say Y here if you are developing drivers or trying to debug and
+ identify kernel problems.
+
+config DEBUG_SHIRQ
+ bool "Debug shared IRQ handlers"
+ depends on DEBUG_KERNEL && GENERIC_HARDIRQS
+ help
+ Enable this to generate a spurious interrupt as soon as a shared
+ interrupt handler is registered, and just before one is deregistered.
+ Drivers ought to be able to handle interrupts coming in at those
+ points; some don't and need to be caught.
config DETECT_SOFTLOCKUP
bool "Detect Soft Lockups"
- depends on DEBUG_KERNEL
+ depends on DEBUG_KERNEL && !S390
default y
help
Say Y here to enable the kernel to detect "soft lockups",
can be detected via the NMI-watchdog, on platforms that
support it.)
+config SCHED_DEBUG
+ bool "Collect scheduler debugging info"
+ depends on DEBUG_KERNEL && PROC_FS
+ default y
+ help
+ If you say Y here, the /proc/sched_debug file will be provided
+ that can help debug the scheduler. The runtime overhead of this
+ option is minimal.
+
config SCHEDSTATS
bool "Collect scheduler statistics"
depends on DEBUG_KERNEL && PROC_FS
application, you can say N to avoid the very slight overhead
this adds.
+config TIMER_STATS
+ bool "Collect kernel timers statistics"
+ depends on DEBUG_KERNEL && PROC_FS
+ help
+ If you say Y here, additional code will be inserted into the
+ timer routines to collect statistics about kernel timers being
+ reprogrammed. The statistics can be read from /proc/timer_stats.
+ The statistics collection is started by writing 1 to /proc/timer_stats,
+ writing 0 stops it. This feature is useful to collect information
+ about timer usage patterns in kernel and userspace. This feature
+ is lightweight if enabled in the kernel config but not activated
+ (it defaults to deactivated on bootup and will only be activated
+ if some application like powertop activates it explicitly).
+
config DEBUG_SLAB
- bool "Debug memory allocations"
- depends on DEBUG_KERNEL
+ bool "Debug slab memory allocations"
+ depends on DEBUG_KERNEL && SLAB
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
memory. This can make kmalloc/kfree-intensive workloads much slower.
+config DEBUG_SLAB_LEAK
+ bool "Memory leak debugging"
+ depends on DEBUG_SLAB
+
+config SLUB_DEBUG_ON
+ bool "SLUB debugging on by default"
+ depends on SLUB && SLUB_DEBUG
+ default n
+ help
+ Boot with debugging on by default. SLUB boots by default with
+ the runtime debug capabilities switched off. Enabling this is
+ equivalent to specifying the "slub_debug" parameter on boot.
+ There is no support for more fine grained debug control like
+ possible with slub_debug=xxx. SLUB debugging may be switched
+ off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
+ "slub_debug=-".
+
config DEBUG_PREEMPT
bool "Debug preemptible kernel"
- depends on DEBUG_KERNEL && PREEMPT
+ depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)
default y
help
If you say Y here then the kernel will use a debug variant of the
if kernel code uses it in a preemption-unsafe way. Also, the kernel
will detect preemption count underflows.
+config DEBUG_RT_MUTEXES
+ bool "RT Mutex debugging, deadlock detection"
+ depends on DEBUG_KERNEL && RT_MUTEXES
+ help
+ This allows rt mutex semantics violations and rt mutex related
+ deadlocks (lockups) to be detected and reported automatically.
+
+config DEBUG_PI_LIST
+ bool
+ default y
+ depends on DEBUG_RT_MUTEXES
+
+config RT_MUTEX_TESTER
+ bool "Built-in scriptable tester for rt-mutexes"
+ depends on DEBUG_KERNEL && RT_MUTEXES
+ help
+ This option enables a rt-mutex tester.
+
config DEBUG_SPINLOCK
- bool "Spinlock debugging"
+ bool "Spinlock and rw-lock debugging: basic checks"
depends on DEBUG_KERNEL
help
Say Y here and build SMP to catch missing spinlock initialization
best used in conjunction with the NMI watchdog so that spinlock
deadlocks are also debuggable.
+config DEBUG_MUTEXES
+ bool "Mutex debugging: basic checks"
+ depends on DEBUG_KERNEL
+ help
+ This feature allows mutex semantics violations to be detected and
+ reported.
+
+config DEBUG_SEMAPHORE
+ bool "Semaphore debugging"
+ depends on DEBUG_KERNEL
+ depends on ALPHA || FRV
+ default n
+ help
+ If you say Y here then semaphore processing will issue lots of
+ verbose debugging messages. If you suspect a semaphore problem or a
+ kernel hacker asks for this option then say Y. Otherwise say N.
+
+config DEBUG_LOCK_ALLOC
+ bool "Lock debugging: detect incorrect freeing of live locks"
+ depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
+ select DEBUG_SPINLOCK
+ select DEBUG_MUTEXES
+ select LOCKDEP
+ help
+ This feature will check whether any held lock (spinlock, rwlock,
+ mutex or rwsem) is incorrectly freed by the kernel, via any of the
+ memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
+ vfree(), etc.), whether a live lock is incorrectly reinitialized via
+ spin_lock_init()/mutex_init()/etc., or whether there is any lock
+ held during task exit.
+
+config PROVE_LOCKING
+ bool "Lock debugging: prove locking correctness"
+ depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
+ select LOCKDEP
+ select DEBUG_SPINLOCK
+ select DEBUG_MUTEXES
+ select DEBUG_LOCK_ALLOC
+ default n
+ help
+ This feature enables the kernel to prove that all locking
+ that occurs in the kernel runtime is mathematically
+ correct: that under no circumstance could an arbitrary (and
+ not yet triggered) combination of observed locking
+ sequences (on an arbitrary number of CPUs, running an
+ arbitrary number of tasks and interrupt contexts) cause a
+ deadlock.
+
+ In short, this feature enables the kernel to report locking
+ related deadlocks before they actually occur.
+
+ The proof does not depend on how hard and complex a
+ deadlock scenario would be to trigger: how many
+ participant CPUs, tasks and irq-contexts would be needed
+ for it to trigger. The proof also does not depend on
+ timing: if a race and a resulting deadlock is possible
+ theoretically (no matter how unlikely the race scenario
+ is), it will be proven so and will immediately be
+ reported by the kernel (once the event is observed that
+ makes the deadlock theoretically possible).
+
+ If a deadlock is impossible (i.e. the locking rules, as
+ observed by the kernel, are mathematically correct), the
+ kernel reports nothing.
+
+ NOTE: this feature can also be enabled for rwlocks, mutexes
+ and rwsems - in which case all dependencies between these
+ different locking variants are observed and mapped too, and
+ the proof of observed correctness is also maintained for an
+ arbitrary combination of these separate locking variants.
+
+ For more details, see Documentation/lockdep-design.txt.
+
+config LOCKDEP
+ bool
+ depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
+ select STACKTRACE
+ select FRAME_POINTER if !X86 && !MIPS
+ select KALLSYMS
+ select KALLSYMS_ALL
+
+config LOCK_STAT
+ bool "Lock usage statisitics"
+ depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
+ select LOCKDEP
+ select DEBUG_SPINLOCK
+ select DEBUG_MUTEXES
+ select DEBUG_LOCK_ALLOC
+ default n
+ help
+ This feature enables tracking lock contention points
+
+config DEBUG_LOCKDEP
+ bool "Lock dependency engine debugging"
+ depends on DEBUG_KERNEL && LOCKDEP
+ help
+ If you say Y here, the lock dependency engine will do
+ additional runtime checks to debug itself, at the price
+ of more runtime overhead.
+
+config TRACE_IRQFLAGS
+ depends on DEBUG_KERNEL
+ bool
+ default y
+ depends on TRACE_IRQFLAGS_SUPPORT
+ depends on PROVE_LOCKING
+
config DEBUG_SPINLOCK_SLEEP
- bool "Sleep-inside-spinlock checking"
+ bool "Spinlock debugging: sleep-inside-spinlock checking"
depends on DEBUG_KERNEL
help
If you say Y here, various routines which may sleep will become very
noisy if they are called with a spinlock held.
+config DEBUG_LOCKING_API_SELFTESTS
+ bool "Locking API boot-time self-tests"
+ depends on DEBUG_KERNEL
+ help
+ Say Y here if you want the kernel to run a short self-test during
+ bootup. The self-test checks whether common types of locking bugs
+ are detected by debugging mechanisms or not. (if you disable
+ lock debugging then those bugs wont be detected of course.)
+ The following locking APIs are covered: spinlocks, rwlocks,
+ mutexes and rwsems.
+
+config STACKTRACE
+ bool
+ depends on DEBUG_KERNEL
+ depends on STACKTRACE_SUPPORT
+
config DEBUG_KOBJECT
bool "kobject debugging"
depends on DEBUG_KERNEL
config DEBUG_BUGVERBOSE
bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
depends on BUG
- depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV
+ depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || FRV || SUPERH || GENERIC_BUG || BFIN
default !EMBEDDED
help
Say Y here to make BUG() panics output the file name and line number
help
If you say Y here the resulting kernel image will include
debugging info resulting in a larger kernel image.
+ This adds debug symbols to the kernel and modules (gcc -g), and
+ is needed if you intend to use kernel crashdump or binary object
+ tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Say Y here only if you plan to debug the kernel.
If unsure, say N.
-config DEBUG_IOREMAP
- bool "Enable ioremap() debugging"
- depends on DEBUG_KERNEL && PARISC
+config DEBUG_VM
+ bool "Debug VM"
+ depends on DEBUG_KERNEL
help
- Enabling this option will cause the kernel to distinguish between
- ioremapped and physical addresses. It will print a backtrace (at
- most one every 10 seconds), hopefully allowing you to see which
- drivers need work. Fixing all these problems is a prerequisite
- for turning on USE_HPPA_IOREMAP. The warnings are harmless;
- the kernel has enough information to fix the broken drivers
- automatically, but we'd like to make it more efficient by not
- having to do that.
+ Enable this to turn on extended checks in the virtual-memory system
+ that may impact performance.
-config DEBUG_FS
- bool "Debug Filesystem"
- depends on DEBUG_KERNEL && SYSFS
+ If unsure, say N.
+
+config DEBUG_LIST
+ bool "Debug linked list manipulation"
+ depends on DEBUG_KERNEL
help
- debugfs is a virtual file system that kernel developers use to put
- debugging files into. Enable this option to be able to read and
- write to these files.
+ Enable this to turn on extended checks in the linked-list
+ walking routines.
If unsure, say N.
config FRAME_POINTER
bool "Compile the kernel with frame pointers"
- depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML)
+ depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390 || AVR32 || SUPERH || BFIN)
default y if DEBUG_INFO && UML
help
If you say Y here the resulting kernel image will be slightly larger
- and slower, but it might give very useful debugging information
- on some architectures or you use external debuggers.
+ and slower, but it might give very useful debugging information on
+ some architectures or if you use external debuggers.
If you don't debug the kernel, you can say N.
+config FORCED_INLINING
+ bool "Force gcc to inline functions marked 'inline'"
+ depends on DEBUG_KERNEL
+ default y
+ help
+ This option determines if the kernel forces gcc to inline the functions
+ developers have marked 'inline'. Doing so takes away freedom from gcc to
+ do what it thinks is best, which is desirable for the gcc 3.x series of
+ compilers. The gcc 4.x series have a rewritten inlining algorithm and
+ disabling this option will generate a smaller kernel there. Hopefully
+ this algorithm is so good that allowing gcc4 to make the decision can
+ become the default in the future, until then this option is there to
+ test gcc for this.
+
+config RCU_TORTURE_TEST
+ tristate "torture tests for RCU"
+ depends on DEBUG_KERNEL
+ depends on m
+ default n
+ help
+ This option provides a kernel module that runs torture tests
+ on the RCU infrastructure. The kernel module may be built
+ after the fact on the running kernel to be tested, if desired.
+
+ Say M if you want the RCU torture tests to build as a module.
+ Say N if you are unsure.
+
+config LKDTM
+ tristate "Linux Kernel Dump Test Tool Module"
+ depends on DEBUG_KERNEL
+ depends on KPROBES
+ default n
+ help
+ This module enables testing of the different dumping mechanisms by
+ inducing system failures at predefined crash points.
+ If you don't need it: say N
+ Choose M here to compile this code as a module. The module will be
+ called lkdtm.
+
+ Documentation on how to use the module can be found in
+ drivers/misc/lkdtm.c
+
+config FAULT_INJECTION
+ bool "Fault-injection framework"
+ depends on DEBUG_KERNEL
+ help
+ Provide fault-injection framework.
+ For more details, see Documentation/fault-injection/.
+
+config FAILSLAB
+ bool "Fault-injection capability for kmalloc"
+ depends on FAULT_INJECTION
+ help
+ Provide fault-injection capability for kmalloc.
+
+config FAIL_PAGE_ALLOC
+ bool "Fault-injection capabilitiy for alloc_pages()"
+ depends on FAULT_INJECTION
+ help
+ Provide fault-injection capability for alloc_pages().
+
+config FAIL_MAKE_REQUEST
+ bool "Fault-injection capability for disk IO"
+ depends on FAULT_INJECTION
+ help
+ Provide fault-injection capability for disk IO.
+
+config FAULT_INJECTION_DEBUG_FS
+ bool "Debugfs entries for fault-injection capabilities"
+ depends on FAULT_INJECTION && SYSFS && DEBUG_FS
+ help
+ Enable configuration of fault-injection capabilities via debugfs.
+
+config FAULT_INJECTION_STACKTRACE_FILTER
+ bool "stacktrace filter for fault-injection capabilities"
+ depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
+ depends on !X86_64
+ select STACKTRACE
+ select FRAME_POINTER
+ help
+ Provide stacktrace filter for fault-injection capabilities