diff options
Diffstat (limited to 'kernel/signal.c')
| -rw-r--r-- | kernel/signal.c | 78 |
1 files changed, 70 insertions, 8 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index 424306163edc..c091dcc9f19b 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -696,6 +696,48 @@ static inline bool si_fromuser(const struct siginfo *info) (!is_si_special(info) && SI_FROMUSER(info)); } +static int dequeue_synchronous_signal(siginfo_t *info) +{ + struct task_struct *tsk = current; + struct sigpending *pending = &tsk->pending; + struct sigqueue *q, *sync = NULL; + + /* + * Might a synchronous signal be in the queue? + */ + if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK)) + return 0; + + /* + * Return the first synchronous signal in the queue. + */ + list_for_each_entry(q, &pending->list, list) { + /* Synchronous signals have a postive si_code */ + if ((q->info.si_code > SI_USER) && + (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) { + sync = q; + goto next; + } + } + return 0; +next: + /* + * Check if there is another siginfo for the same signal. + */ + list_for_each_entry_continue(q, &pending->list, list) { + if (q->info.si_signo == sync->info.si_signo) + goto still_pending; + } + + sigdelset(&pending->signal, sync->info.si_signo); + recalc_sigpending(); +still_pending: + list_del_init(&sync->list); + copy_siginfo(info, &sync->info); + __sigqueue_free(sync); + return info->si_signo; +} + /* * called with RCU read lock from check_kill_permission() */ @@ -2198,6 +2240,14 @@ relock: goto relock; } + /* Has this task already been marked for death? */ + if (signal_group_exit(signal)) { + ksig->info.si_signo = signr = SIGKILL; + sigdelset(¤t->pending.signal, SIGKILL); + recalc_sigpending(); + goto fatal; + } + for (;;) { struct k_sigaction *ka; @@ -2211,7 +2261,15 @@ relock: goto relock; } - signr = dequeue_signal(current, ¤t->blocked, &ksig->info); + /* + * Signals generated by the execution of an instruction + * need to be delivered before any other pending signals + * so that the instruction pointer in the signal stack + * frame points to the faulting instruction. + */ + signr = dequeue_synchronous_signal(&ksig->info); + if (!signr) + signr = dequeue_signal(current, ¤t->blocked, &ksig->info); if (!signr) break; /* will return 0 */ @@ -2293,6 +2351,7 @@ relock: continue; } + fatal: spin_unlock_irq(&sighand->siglock); /* @@ -3116,7 +3175,8 @@ int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) } static int -do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) +do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp, + size_t min_ss_size) { stack_t oss; int error; @@ -3155,9 +3215,8 @@ do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long s ss_size = 0; ss_sp = NULL; } else { - error = -ENOMEM; - if (ss_size < MINSIGSTKSZ) - goto out; + if (unlikely(ss_size < min_ss_size)) + return -ENOMEM; } current->sas_ss_sp = (unsigned long) ss_sp; @@ -3180,12 +3239,14 @@ out: } SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss) { - return do_sigaltstack(uss, uoss, current_user_stack_pointer()); + return do_sigaltstack(uss, uoss, current_user_stack_pointer(), + MINSIGSTKSZ); } int restore_altstack(const stack_t __user *uss) { - int err = do_sigaltstack(uss, NULL, current_user_stack_pointer()); + int err = do_sigaltstack(uss, NULL, current_user_stack_pointer(), + MINSIGSTKSZ); /* squash all but EFAULT for now */ return err == -EFAULT ? err : 0; } @@ -3226,7 +3287,8 @@ COMPAT_SYSCALL_DEFINE2(sigaltstack, set_fs(KERNEL_DS); ret = do_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL), (stack_t __force __user *) &uoss, - compat_user_stack_pointer()); + compat_user_stack_pointer(), + COMPAT_MINSIGSTKSZ); set_fs(seg); if (ret >= 0 && uoss_ptr) { if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(compat_stack_t)) || |