X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=kernel%2Fsignal.c;h=1814e68e4de38297d0fcf1a8d2c1caa6056354d3;hb=9209e4bd4b3b9ee3a104313b426380e8d1f59260;hp=6705320784fd2b07a518c4d2bb47520d0b342aa8;hpb=dede17b8e931eeaa38b0288e8d545d558d904942;p=~andy%2Flinux diff --git a/kernel/signal.c b/kernel/signal.c index 6705320784f..1814e68e4de 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -22,12 +22,14 @@ #include #include #include +#include #include #include #include #include #include -#include +#define CREATE_TRACE_POINTS +#include #include #include @@ -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); @@ -400,7 +423,7 @@ still_pending: */ 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; } @@ -584,6 +607,17 @@ static int rm_from_queue(unsigned long mask, struct sigpending *s) 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 @@ -598,7 +632,7 @@ static int check_kill_permission(int sig, struct siginfo *info, 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 */ @@ -834,7 +868,7 @@ 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 +903,7 @@ 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 +930,21 @@ 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: @@ -917,16 +960,13 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t, 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", @@ -1022,12 +1062,6 @@ force_sig_info(int sig, struct siginfo *info, struct task_struct *t) 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. */ @@ -1156,8 +1190,7 @@ int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid, 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; @@ -1293,19 +1326,19 @@ 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) @@ -1807,11 +1840,6 @@ 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, @@ -1823,6 +1851,10 @@ relock: 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); @@ -1839,6 +1871,9 @@ 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) {