#include <linux/ptrace.h>
#include <linux/signal.h>
#include <linux/signalfd.h>
+#include <linux/ratelimit.h>
#include <linux/tracehook.h>
#include <linux/capability.h>
#include <linux/freezer.h>
#include <linux/pid_namespace.h>
#include <linux/nsproxy.h>
-#include <trace/sched.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/signal.h>
#include <asm/param.h>
#include <asm/uaccess.h>
static struct kmem_cache *sigqueue_cachep;
-DEFINE_TRACE(sched_signal_send);
+int print_fatal_signals __read_mostly;
static void __user *sig_handler(struct task_struct *t, int sig)
{
/* Given the mask, find the first available signal that should be serviced. */
+#define SYNCHRONOUS_MASK \
+ (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
+ sigmask(SIGTRAP) | sigmask(SIGFPE))
+
int next_signal(struct sigpending *pending, sigset_t *mask)
{
unsigned long i, *s, *m, x;
int sig = 0;
-
+
s = pending->signal.sig;
m = mask->sig;
+
+ /*
+ * Handle the first word specially: it contains the
+ * synchronous signals that need to be dequeued first.
+ */
+ x = *s &~ *m;
+ if (x) {
+ if (x & SYNCHRONOUS_MASK)
+ x &= SYNCHRONOUS_MASK;
+ sig = ffz(~x) + 1;
+ return sig;
+ }
+
switch (_NSIG_WORDS) {
default:
- for (i = 0; i < _NSIG_WORDS; ++i, ++s, ++m)
- if ((x = *s &~ *m) != 0) {
- sig = ffz(~x) + i*_NSIG_BPW + 1;
- break;
- }
+ for (i = 1; i < _NSIG_WORDS; ++i) {
+ x = *++s &~ *++m;
+ if (!x)
+ continue;
+ sig = ffz(~x) + i*_NSIG_BPW + 1;
+ break;
+ }
break;
- case 2: if ((x = s[0] &~ m[0]) != 0)
- sig = 1;
- else if ((x = s[1] &~ m[1]) != 0)
- sig = _NSIG_BPW + 1;
- else
+ case 2:
+ x = s[1] &~ m[1];
+ if (!x)
break;
- sig += ffz(~x);
+ sig = ffz(~x) + _NSIG_BPW + 1;
break;
- case 1: if ((x = *s &~ *m) != 0)
- sig = ffz(~x) + 1;
+ case 1:
+ /* Nothing to do */
break;
}
-
+
return sig;
}
+static inline void print_dropped_signal(int sig)
+{
+ static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
+
+ if (!print_fatal_signals)
+ return;
+
+ if (!__ratelimit(&ratelimit_state))
+ return;
+
+ printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
+ current->comm, current->pid, sig);
+}
+
/*
* allocate a new signal queue record
* - this may be called without locks if and only if t == current, otherwise an
* appopriate lock must be held to stop the target task from exiting
*/
-static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
- int override_rlimit)
+static struct sigqueue *
+__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
{
struct sigqueue *q = NULL;
struct user_struct *user;
/*
- * We won't get problems with the target's UID changing under us
- * because changing it requires RCU be used, and if t != current, the
- * caller must be holding the RCU readlock (by way of a spinlock) and
- * we use RCU protection here
+ * Protect access to @t credentials. This can go away when all
+ * callers hold rcu read lock.
*/
+ rcu_read_lock();
user = get_uid(__task_cred(t)->user);
atomic_inc(&user->sigpending);
+ rcu_read_unlock();
+
if (override_rlimit ||
atomic_read(&user->sigpending) <=
- t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur)
+ task_rlimit(t, RLIMIT_SIGPENDING)) {
q = kmem_cache_alloc(sigqueue_cachep, flags);
+ } else {
+ print_dropped_signal(sig);
+ }
+
if (unlikely(q == NULL)) {
atomic_dec(&user->sigpending);
free_uid(user);
/*
* Flush all pending signals for a task.
*/
+void __flush_signals(struct task_struct *t)
+{
+ clear_tsk_thread_flag(t, TIF_SIGPENDING);
+ flush_sigqueue(&t->pending);
+ flush_sigqueue(&t->signal->shared_pending);
+}
+
void flush_signals(struct task_struct *t)
{
unsigned long flags;
spin_lock_irqsave(&t->sighand->siglock, flags);
- clear_tsk_thread_flag(t, TIF_SIGPENDING);
- flush_sigqueue(&t->pending);
- flush_sigqueue(&t->signal->shared_pending);
+ __flush_signals(t);
spin_unlock_irqrestore(&t->sighand->siglock, flags);
}
*/
info->si_signo = sig;
info->si_errno = 0;
- info->si_code = 0;
+ info->si_code = SI_USER;
info->si_pid = 0;
info->si_uid = 0;
}
return 1;
}
+static inline int is_si_special(const struct siginfo *info)
+{
+ return info <= SEND_SIG_FORCED;
+}
+
+static inline bool si_fromuser(const struct siginfo *info)
+{
+ return info == SEND_SIG_NOINFO ||
+ (!is_si_special(info) && SI_FROMUSER(info));
+}
+
/*
* Bad permissions for sending the signal
* - the caller must hold at least the RCU read lock
if (!valid_signal(sig))
return -EINVAL;
- if (info != SEND_SIG_NOINFO && (is_si_special(info) || SI_FROMKERNEL(info)))
+ if (!si_fromuser(info))
return 0;
error = audit_signal_info(sig, t); /* Let audit system see the signal */
if (why) {
/*
- * The first thread which returns from finish_stop()
+ * The first thread which returns from do_signal_stop()
* will take ->siglock, notice SIGNAL_CLD_MASK, and
* notify its parent. See get_signal_to_deliver().
*/
{
struct sigpending *pending;
struct sigqueue *q;
+ int override_rlimit;
- trace_sched_signal_send(sig, t);
+ trace_signal_generate(sig, info, t);
assert_spin_locked(&t->sighand->siglock);
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(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
+ override_rlimit);
if (q) {
list_add_tail(&q->list, &pending->list);
switch ((unsigned long) info) {
break;
}
} else if (!is_si_special(info)) {
- if (sig >= SIGRTMIN && info->si_code != SI_USER)
- /*
- * Queue overflow, abort. We may abort if the signal was rt
- * and sent by user using something other than kill().
- */
+ if (sig >= SIGRTMIN && info->si_code != SI_USER) {
+ /*
+ * Queue overflow, abort. We may abort if the
+ * signal was rt and sent by user using something
+ * other than kill().
+ */
+ trace_signal_overflow_fail(sig, group, info);
return -EAGAIN;
+ } else {
+ /*
+ * This is a silent loss of information. We still
+ * send the signal, but the *info bits are lost.
+ */
+ trace_signal_lose_info(sig, group, info);
+ }
}
out_set:
int from_ancestor_ns = 0;
#ifdef CONFIG_PID_NS
- if (!is_si_special(info) && SI_FROMUSER(info) &&
- task_pid_nr_ns(current, task_active_pid_ns(t)) <= 0)
- from_ancestor_ns = 1;
+ from_ancestor_ns = si_fromuser(info) &&
+ !task_pid_nr_ns(current, task_active_pid_ns(t));
#endif
return __send_signal(sig, info, t, group, from_ancestor_ns);
}
-int print_fatal_signals;
-
static void print_fatal_signal(struct pt_regs *regs, int signr)
{
printk("%s/%d: potentially unexpected fatal signal %d.\n",
for (i = 0; i < 16; i++) {
unsigned char insn;
- __get_user(insn, (unsigned char *)(regs->ip + i));
+ if (get_user(insn, (unsigned char *)(regs->ip + i)))
+ break;
printk("%02x ", insn);
}
}
return send_signal(sig, info, t, 0);
}
+int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
+ bool group)
+{
+ unsigned long flags;
+ int ret = -ESRCH;
+
+ if (lock_task_sighand(p, &flags)) {
+ ret = send_signal(sig, info, p, group);
+ unlock_task_sighand(p, &flags);
+ }
+
+ return ret;
+}
+
/*
* Force a signal that the process can't ignore: if necessary
* we unblock the signal and change any SIG_IGN to SIG_DFL.
return ret;
}
-void
-force_sig_specific(int sig, struct task_struct *t)
-{
- force_sig_info(sig, SEND_SIG_FORCED, t);
-}
-
/*
* Nuke all other threads in the group.
*/
}
}
-int __fatal_signal_pending(struct task_struct *tsk)
-{
- return sigismember(&tsk->pending.signal, SIGKILL);
-}
-EXPORT_SYMBOL(__fatal_signal_pending);
-
struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags)
{
struct sighand_struct *sighand;
*/
int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
- unsigned long flags;
- int ret;
+ int ret = check_kill_permission(sig, info, p);
- ret = check_kill_permission(sig, info, p);
-
- if (!ret && sig) {
- ret = -ESRCH;
- if (lock_task_sighand(p, &flags)) {
- ret = __group_send_sig_info(sig, info, p);
- unlock_task_sighand(p, &flags);
- }
- }
+ if (!ret && sig)
+ ret = do_send_sig_info(sig, info, p, true);
return ret;
}
int ret = -EINVAL;
struct task_struct *p;
const struct cred *pcred;
+ unsigned long flags;
if (!valid_signal(sig))
return ret;
- read_lock(&tasklist_lock);
+ rcu_read_lock();
p = pid_task(pid, PIDTYPE_PID);
if (!p) {
ret = -ESRCH;
goto out_unlock;
}
pcred = __task_cred(p);
- if ((info == SEND_SIG_NOINFO ||
- (!is_si_special(info) && SI_FROMUSER(info))) &&
+ if (si_fromuser(info) &&
euid != pcred->suid && euid != pcred->uid &&
uid != pcred->suid && uid != pcred->uid) {
ret = -EPERM;
ret = security_task_kill(p, info, sig, secid);
if (ret)
goto out_unlock;
- if (sig && p->sighand) {
- unsigned long flags;
- spin_lock_irqsave(&p->sighand->siglock, flags);
- ret = __send_signal(sig, info, p, 1, 0);
- spin_unlock_irqrestore(&p->sighand->siglock, flags);
+
+ if (sig) {
+ if (lock_task_sighand(p, &flags)) {
+ ret = __send_signal(sig, info, p, 1, 0);
+ unlock_task_sighand(p, &flags);
+ } else
+ ret = -ESRCH;
}
out_unlock:
- read_unlock(&tasklist_lock);
+ rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
* These are for backward compatibility with the rest of the kernel source.
*/
-/*
- * The caller must ensure the task can't exit.
- */
int
send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
- int ret;
- unsigned long flags;
-
/*
* Make sure legacy kernel users don't send in bad values
* (normal paths check this in check_kill_permission).
if (!valid_signal(sig))
return -EINVAL;
- spin_lock_irqsave(&p->sighand->siglock, flags);
- ret = specific_send_sig_info(sig, info, p);
- spin_unlock_irqrestore(&p->sighand->siglock, flags);
- return ret;
+ return do_send_sig_info(sig, info, p, false);
}
#define __si_special(priv) \
* These functions support sending signals using preallocated sigqueue
* structures. This is needed "because realtime applications cannot
* afford to lose notifications of asynchronous events, like timer
- * expirations or I/O completions". In the case of Posix Timers
+ * expirations or I/O completions". In the case of Posix Timers
* we allocate the sigqueue structure from the timer_create. If this
* allocation fails we are able to report the failure to the application
* with an EAGAIN error.
*/
-
struct sigqueue *sigqueue_alloc(void)
{
- struct sigqueue *q;
+ struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
- if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0)))
+ if (q)
q->flags |= SIGQUEUE_PREALLOC;
- return(q);
+
+ return q;
}
void sigqueue_free(struct sigqueue *q)
}
/*
- * Wake up any threads in the parent blocked in wait* syscalls.
- */
-static inline void __wake_up_parent(struct task_struct *p,
- struct task_struct *parent)
-{
- wake_up_interruptible_sync(&parent->signal->wait_chldexit);
-}
-
-/*
* Let a parent know about the death of a child.
* For a stopped/continued status change, use do_notify_parent_cldstop instead.
*
/* do_notify_parent_cldstop should have been called instead. */
BUG_ON(task_is_stopped_or_traced(tsk));
- BUG_ON(!tsk->ptrace &&
+ BUG_ON(!task_ptrace(tsk) &&
(tsk->group_leader != tsk || !thread_group_empty(tsk)));
info.si_signo = sig;
psig = tsk->parent->sighand;
spin_lock_irqsave(&psig->siglock, flags);
- if (!tsk->ptrace && sig == SIGCHLD &&
+ if (!task_ptrace(tsk) && sig == SIGCHLD &&
(psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
(psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
/*
struct task_struct *parent;
struct sighand_struct *sighand;
- if (tsk->ptrace & PT_PTRACED)
+ if (task_ptrace(tsk))
parent = tsk->parent;
else {
tsk = tsk->group_leader;
* see comment in do_notify_parent() abot the following 3 lines
*/
rcu_read_lock();
- info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
+ info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns);
info.si_uid = __task_cred(tsk)->uid;
rcu_read_unlock();
static inline int may_ptrace_stop(void)
{
- if (!likely(current->ptrace & PT_PTRACED))
+ if (!likely(task_ptrace(current)))
return 0;
/*
* Are we in the middle of do_coredump?
spin_unlock_irq(¤t->sighand->siglock);
}
-static void
-finish_stop(int stop_count)
-{
- /*
- * If there are no other threads in the group, or if there is
- * a group stop in progress and we are the last to stop,
- * report to the parent. When ptraced, every thread reports itself.
- */
- if (tracehook_notify_jctl(stop_count == 0, CLD_STOPPED)) {
- read_lock(&tasklist_lock);
- do_notify_parent_cldstop(current, CLD_STOPPED);
- read_unlock(&tasklist_lock);
- }
-
- do {
- schedule();
- } while (try_to_freeze());
- /*
- * Now we don't run again until continued.
- */
- current->exit_code = 0;
-}
-
/*
* This performs the stopping for SIGSTOP and other stop signals.
* We have to stop all threads in the thread group.
static int do_signal_stop(int signr)
{
struct signal_struct *sig = current->signal;
- int stop_count;
+ int notify;
- if (sig->group_stop_count > 0) {
- /*
- * There is a group stop in progress. We don't need to
- * start another one.
- */
- stop_count = --sig->group_stop_count;
- } else {
+ if (!sig->group_stop_count) {
struct task_struct *t;
if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) ||
*/
sig->group_exit_code = signr;
- stop_count = 0;
+ sig->group_stop_count = 1;
for (t = next_thread(current); t != current; t = next_thread(t))
/*
* Setting state to TASK_STOPPED for a group
*/
if (!(t->flags & PF_EXITING) &&
!task_is_stopped_or_traced(t)) {
- stop_count++;
+ sig->group_stop_count++;
signal_wake_up(t, 0);
}
- sig->group_stop_count = stop_count;
}
+ /*
+ * If there are no other threads in the group, or if there is
+ * a group stop in progress and we are the last to stop, report
+ * to the parent. When ptraced, every thread reports itself.
+ */
+ notify = sig->group_stop_count == 1 ? CLD_STOPPED : 0;
+ notify = tracehook_notify_jctl(notify, CLD_STOPPED);
+ /*
+ * tracehook_notify_jctl() can drop and reacquire siglock, so
+ * we keep ->group_stop_count != 0 before the call. If SIGCONT
+ * or SIGKILL comes in between ->group_stop_count == 0.
+ */
+ if (sig->group_stop_count) {
+ if (!--sig->group_stop_count)
+ sig->flags = SIGNAL_STOP_STOPPED;
+ current->exit_code = sig->group_exit_code;
+ __set_current_state(TASK_STOPPED);
+ }
+ spin_unlock_irq(¤t->sighand->siglock);
- if (stop_count == 0)
- sig->flags = SIGNAL_STOP_STOPPED;
- current->exit_code = sig->group_exit_code;
- __set_current_state(TASK_STOPPED);
+ if (notify) {
+ read_lock(&tasklist_lock);
+ do_notify_parent_cldstop(current, notify);
+ read_unlock(&tasklist_lock);
+ }
+
+ /* Now we don't run again until woken by SIGCONT or SIGKILL */
+ do {
+ schedule();
+ } while (try_to_freeze());
+
+ tracehook_finish_jctl();
+ current->exit_code = 0;
- spin_unlock_irq(¤t->sighand->siglock);
- finish_stop(stop_count);
return 1;
}
static int ptrace_signal(int signr, siginfo_t *info,
struct pt_regs *regs, void *cookie)
{
- if (!(current->ptrace & PT_PTRACED))
+ if (!task_ptrace(current))
return signr;
ptrace_signal_deliver(regs, cookie);
int why = (signal->flags & SIGNAL_STOP_CONTINUED)
? CLD_CONTINUED : CLD_STOPPED;
signal->flags &= ~SIGNAL_CLD_MASK;
- spin_unlock_irq(&sighand->siglock);
- if (unlikely(!tracehook_notify_jctl(1, why)))
- goto relock;
+ why = tracehook_notify_jctl(why, CLD_CONTINUED);
+ spin_unlock_irq(&sighand->siglock);
- read_lock(&tasklist_lock);
- do_notify_parent_cldstop(current->group_leader, why);
- read_unlock(&tasklist_lock);
+ if (why) {
+ read_lock(&tasklist_lock);
+ do_notify_parent_cldstop(current->group_leader, why);
+ read_unlock(&tasklist_lock);
+ }
goto relock;
}
for (;;) {
struct k_sigaction *ka;
-
- if (unlikely(signal->group_stop_count > 0) &&
- do_signal_stop(0))
- goto relock;
-
/*
* Tracing can induce an artifical signal and choose sigaction.
* The return value in @signr determines the default action,
if (unlikely(signr != 0))
ka = return_ka;
else {
+ if (unlikely(signal->group_stop_count > 0) &&
+ do_signal_stop(0))
+ goto relock;
+
signr = dequeue_signal(current, ¤t->blocked,
info);
ka = &sighand->action[signr-1];
}
+ /* Trace actually delivered signals. */
+ trace_signal_deliver(signr, info, ka);
+
if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
continue;
if (ka->sa.sa_handler != SIG_DFL) {
if (unlikely(tsk->signal->group_stop_count) &&
!--tsk->signal->group_stop_count) {
tsk->signal->flags = SIGNAL_STOP_STOPPED;
- group_stop = 1;
+ group_stop = tracehook_notify_jctl(CLD_STOPPED, CLD_STOPPED);
}
out:
spin_unlock_irq(&tsk->sighand->siglock);
- if (unlikely(group_stop) && tracehook_notify_jctl(1, CLD_STOPPED)) {
+ if (unlikely(group_stop)) {
read_lock(&tasklist_lock);
- do_notify_parent_cldstop(tsk, CLD_STOPPED);
+ do_notify_parent_cldstop(tsk, group_stop);
read_unlock(&tasklist_lock);
}
}
do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
{
struct task_struct *p;
- unsigned long flags;
int error = -ESRCH;
rcu_read_lock();
/*
* The null signal is a permissions and process existence
* probe. No signal is actually delivered.
- *
- * If lock_task_sighand() fails we pretend the task dies
- * after receiving the signal. The window is tiny, and the
- * signal is private anyway.
*/
- if (!error && sig && lock_task_sighand(p, &flags)) {
- error = specific_send_sig_info(sig, info, p);
- unlock_task_sighand(p, &flags);
+ if (!error && sig) {
+ error = do_send_sig_info(sig, info, p, false);
+ /*
+ * If lock_task_sighand() failed we pretend the task
+ * dies after receiving the signal. The window is tiny,
+ * and the signal is private anyway.
+ */
+ if (unlikely(error == -ESRCH))
+ error = 0;
}
}
rcu_read_unlock();
stack_t oss;
int error;
- if (uoss) {
- oss.ss_sp = (void __user *) current->sas_ss_sp;
- oss.ss_size = current->sas_ss_size;
- oss.ss_flags = sas_ss_flags(sp);
- }
+ oss.ss_sp = (void __user *) current->sas_ss_sp;
+ oss.ss_size = current->sas_ss_size;
+ oss.ss_flags = sas_ss_flags(sp);
if (uss) {
void __user *ss_sp;
int ss_flags;
error = -EFAULT;
- if (!access_ok(VERIFY_READ, uss, sizeof(*uss))
- || __get_user(ss_sp, &uss->ss_sp)
- || __get_user(ss_flags, &uss->ss_flags)
- || __get_user(ss_size, &uss->ss_size))
+ if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
+ goto out;
+ error = __get_user(ss_sp, &uss->ss_sp) |
+ __get_user(ss_flags, &uss->ss_flags) |
+ __get_user(ss_size, &uss->ss_size);
+ if (error)
goto out;
error = -EPERM;
current->sas_ss_size = ss_size;
}
+ error = 0;
if (uoss) {
error = -EFAULT;
- if (copy_to_user(uoss, &oss, sizeof(oss)))
+ if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
goto out;
+ error = __put_user(oss.ss_sp, &uoss->ss_sp) |
+ __put_user(oss.ss_size, &uoss->ss_size) |
+ __put_user(oss.ss_flags, &uoss->ss_flags);
}
- error = 0;
out:
return error;
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff