Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[sfrench/cifs-2.6.git] / kernel / signal.c

diff --git a/kernel/signal.c b/kernel/signal.c
index 6705320784fd2b07a518c4d2bb47520d0b342aa8..6b982f2cf524d82e6b72f276f7d9010df9007e47 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -22,12 +22,14 @@
 #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/events/sched.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/signal.h>
 
 #include <asm/param.h>
 #include <asm/uaccess.h>
@@ -41,6 +43,8 @@
 
 static struct kmem_cache *sigqueue_cachep;
 
+int print_fatal_signals __read_mostly;
+
 static void __user *sig_handler(struct task_struct *t, int sig)
 {
        return t->sighand->action[sig - 1].sa.sa_handler;
@@ -159,7 +163,7 @@ 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;
        switch (_NSIG_WORDS) {
@@ -184,17 +188,31 @@ int next_signal(struct sigpending *pending, sigset_t *mask)
                        sig = ffz(~x) + 1;
                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;
@@ -207,10 +225,15 @@ static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
         */
        user = get_uid(__task_cred(t)->user);
        atomic_inc(&user->sigpending);
+
        if (override_rlimit ||
            atomic_read(&user->sigpending) <=
-                       t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur)
+                       t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) {
                q = kmem_cache_alloc(sigqueue_cachep, flags);
+       } else {
+               print_dropped_signal(sig);
+       }
+
        if (unlikely(q == NULL)) {
                atomic_dec(&user->sigpending);
                free_uid(user);
@@ -834,7 +857,7 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
        struct sigqueue *q;
        int override_rlimit;
 
-       trace_sched_signal_send(sig, t);
+       trace_signal_generate(sig, info, t);
 
        assert_spin_locked(&t->sighand->siglock);
 
@@ -869,7 +892,7 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
        else
                override_rlimit = 0;
 
-       q = __sigqueue_alloc(t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
+       q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
                override_rlimit);
        if (q) {
                list_add_tail(&q->list, &pending->list);
@@ -896,12 +919,21 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
                        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:
@@ -925,8 +957,6 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
        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",
@@ -1293,19 +1323,19 @@ EXPORT_SYMBOL(kill_pid);
  * 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)
@@ -1839,6 +1869,9 @@ relock:
                        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) {