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Commit 69f061e0 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'core-signal-for-linus' of... 

Merge branch 'core-signal-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-signal-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  signal: Print warning message when dropping signals
  signal: Fix alternate signal stack check
parents 60778176 f84d49b2

Documentation/kernel-parameters.txt

+9 −2
Original line number Diff line number Diff line
@@ -2031,8 +2031,15 @@ and is between 256 and 4096 characters. It is defined in the file 


	print-fatal-signals=

			[KNL] debug: print fatal signals

			print-fatal-signals=1: print segfault info to

			the kernel console.



			If enabled, warn about various signal handling

			related application anomalies: too many signals,

			too many POSIX.1 timers, fatal signals causing a

			coredump - etc.



			If you hit the warning due to signal overflow,

			you might want to try "ulimit -i unlimited".



			default: off.



	printk.time=	Show timing data prefixed to each printk message line

include/linux/sched.h

+10 −3
Original line number Diff line number Diff line
@@ -2086,11 +2086,18 @@ static inline int is_si_special(const struct siginfo *info) 
	return info <= SEND_SIG_FORCED;

}



/* True if we are on the alternate signal stack.  */



/*

 * True if we are on the alternate signal stack.

 */

static inline int on_sig_stack(unsigned long sp)

{

	return (sp - current->sas_ss_sp < current->sas_ss_size);

#ifdef CONFIG_STACK_GROWSUP

	return sp >= current->sas_ss_sp &&

		sp - current->sas_ss_sp < current->sas_ss_size;

#else

	return sp > current->sas_ss_sp &&

		sp - current->sas_ss_sp <= current->sas_ss_size;

#endif

}



static inline int sas_ss_flags(unsigned long sp)

kernel/signal.c

+33 −13
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
#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>
@@ -41,6 +42,8 @@ 


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;
@@ -188,13 +191,27 @@ int next_signal(struct sigpending *pending, sigset_t *mask) 
	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 +224,15 @@ 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);
@@ -869,7 +891,7 @@ 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);
@@ -925,8 +947,6 @@ 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",
@@ -1298,14 +1318,14 @@ EXPORT_SYMBOL(kill_pid); 
 * 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)