diff options
Diffstat (limited to 'kernel/signal.c')
| -rw-r--r-- | kernel/signal.c | 96 |
1 files changed, 66 insertions, 30 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index d6251951583f..792952381092 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -255,6 +255,16 @@ flush_signal_handlers(struct task_struct *t, int force_default) } } +int unhandled_signal(struct task_struct *tsk, int sig) +{ + if (is_init(tsk)) + return 1; + if (tsk->ptrace & PT_PTRACED) + return 0; + return (tsk->sighand->action[sig-1].sa.sa_handler == SIG_IGN) || + (tsk->sighand->action[sig-1].sa.sa_handler == SIG_DFL); +} + /* Notify the system that a driver wants to block all signals for this * process, and wants to be notified if any signals at all were to be @@ -368,8 +378,7 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) /* We only dequeue private signals from ourselves, we don't let * signalfd steal them */ - if (likely(tsk == current)) - signr = __dequeue_signal(&tsk->pending, mask, info); + signr = __dequeue_signal(&tsk->pending, mask, info); if (!signr) { signr = __dequeue_signal(&tsk->signal->shared_pending, mask, info); @@ -397,8 +406,7 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) } } } - if (likely(tsk == current)) - recalc_sigpending(); + recalc_sigpending(); if (signr && unlikely(sig_kernel_stop(signr))) { /* * Set a marker that we have dequeued a stop signal. Our @@ -415,7 +423,7 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; } - if (signr && likely(tsk == current) && + if (signr && ((info->si_code & __SI_MASK) == __SI_TIMER) && info->si_sys_private){ /* @@ -523,18 +531,18 @@ static int check_kill_permission(int sig, struct siginfo *info, if (!valid_signal(sig)) return error; - error = audit_signal_info(sig, t); /* Let audit system see the signal */ - if (error) - return error; - - error = -EPERM; - if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info))) - && ((sig != SIGCONT) || - (process_session(current) != process_session(t))) - && (current->euid ^ t->suid) && (current->euid ^ t->uid) - && (current->uid ^ t->suid) && (current->uid ^ t->uid) - && !capable(CAP_KILL)) + if (info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info))) { + error = audit_signal_info(sig, t); /* Let audit system see the signal */ + if (error) + return error; + error = -EPERM; + if (((sig != SIGCONT) || + (process_session(current) != process_session(t))) + && (current->euid ^ t->suid) && (current->euid ^ t->uid) + && (current->uid ^ t->suid) && (current->uid ^ t->uid) + && !capable(CAP_KILL)) return error; + } return security_task_kill(t, info, sig, 0); } @@ -718,6 +726,37 @@ out_set: #define LEGACY_QUEUE(sigptr, sig) \ (((sig) < SIGRTMIN) && sigismember(&(sigptr)->signal, (sig))) +int print_fatal_signals; + +static void print_fatal_signal(struct pt_regs *regs, int signr) +{ + printk("%s/%d: potentially unexpected fatal signal %d.\n", + current->comm, current->pid, signr); + +#ifdef __i386__ + printk("code at %08lx: ", regs->eip); + { + int i; + for (i = 0; i < 16; i++) { + unsigned char insn; + + __get_user(insn, (unsigned char *)(regs->eip + i)); + printk("%02x ", insn); + } + } +#endif + printk("\n"); + show_regs(regs); +} + +static int __init setup_print_fatal_signals(char *str) +{ + get_option (&str, &print_fatal_signals); + + return 1; +} + +__setup("print-fatal-signals=", setup_print_fatal_signals); static int specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) @@ -1259,20 +1298,19 @@ struct sigqueue *sigqueue_alloc(void) void sigqueue_free(struct sigqueue *q) { unsigned long flags; + spinlock_t *lock = ¤t->sighand->siglock; + BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); /* * If the signal is still pending remove it from the - * pending queue. + * pending queue. We must hold ->siglock while testing + * q->list to serialize with collect_signal(). */ - if (unlikely(!list_empty(&q->list))) { - spinlock_t *lock = ¤t->sighand->siglock; - read_lock(&tasklist_lock); - spin_lock_irqsave(lock, flags); - if (!list_empty(&q->list)) - list_del_init(&q->list); - spin_unlock_irqrestore(lock, flags); - read_unlock(&tasklist_lock); - } + spin_lock_irqsave(lock, flags); + if (!list_empty(&q->list)) + list_del_init(&q->list); + spin_unlock_irqrestore(lock, flags); + q->flags &= ~SIGQUEUE_PREALLOC; __sigqueue_free(q); } @@ -1520,10 +1558,6 @@ static inline int may_ptrace_stop(void) (current->ptrace & PT_ATTACHED))) return 0; - if (unlikely(current->signal == current->parent->signal) && - unlikely(current->signal->flags & SIGNAL_GROUP_EXIT)) - return 0; - /* * Are we in the middle of do_coredump? * If so and our tracer is also part of the coredump stopping @@ -1855,6 +1889,8 @@ relock: * Anything else is fatal, maybe with a core dump. */ current->flags |= PF_SIGNALED; + if ((signr != SIGKILL) && print_fatal_signals) + print_fatal_signal(regs, signr); if (sig_kernel_coredump(signr)) { /* * If it was able to dump core, this kills all |