X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fsignal.c;h=72bb4f51f9634c448ad6eb4986d8ed7f35deb1f1;hb=dd5656e59ca7b25fb60a22f9079905ed0da5ed0c;hp=3169bed0b4d0e44166b37c48ed663d516a9ccba5;hpb=60187d2708caa870f0825d753df1612ea688eb9e;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/signal.c b/kernel/signal.c index 3169bed..72bb4f5 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -39,11 +39,19 @@ static struct kmem_cache *sigqueue_cachep; +static int __sig_ignored(struct task_struct *t, int sig) +{ + void __user *handler; + + /* Is it explicitly or implicitly ignored? */ + + handler = t->sighand->action[sig - 1].sa.sa_handler; + return handler == SIG_IGN || + (handler == SIG_DFL && sig_kernel_ignore(sig)); +} static int sig_ignored(struct task_struct *t, int sig) { - void __user * handler; - /* * Tracers always want to know about signals.. */ @@ -55,13 +63,10 @@ static int sig_ignored(struct task_struct *t, int sig) * signal handler may change by the time it is * unblocked. */ - if (sigismember(&t->blocked, sig)) + if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) return 0; - /* Is it explicitly or implicitly ignored? */ - handler = t->sighand->action[sig-1].sa.sa_handler; - return handler == SIG_IGN || - (handler == SIG_DFL && sig_kernel_ignore(sig)); + return __sig_ignored(t, sig); } /* @@ -99,7 +104,6 @@ static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) static int recalc_sigpending_tsk(struct task_struct *t) { if (t->signal->group_stop_count > 0 || - (freezing(t)) || PENDING(&t->pending, &t->blocked) || PENDING(&t->signal->shared_pending, &t->blocked)) { set_tsk_thread_flag(t, TIF_SIGPENDING); @@ -125,7 +129,7 @@ void recalc_sigpending_and_wake(struct task_struct *t) void recalc_sigpending(void) { - if (!recalc_sigpending_tsk(current)) + if (!recalc_sigpending_tsk(current) && !freezing(current)) clear_thread_flag(TIF_SIGPENDING); } @@ -221,7 +225,7 @@ void flush_signals(struct task_struct *t) unsigned long flags; spin_lock_irqsave(&t->sighand->siglock, flags); - clear_tsk_thread_flag(t,TIF_SIGPENDING); + clear_tsk_thread_flag(t, TIF_SIGPENDING); flush_sigqueue(&t->pending); flush_sigqueue(&t->signal->shared_pending); spin_unlock_irqrestore(&t->sighand->siglock, flags); @@ -257,7 +261,7 @@ flush_signal_handlers(struct task_struct *t, int force_default) int unhandled_signal(struct task_struct *tsk, int sig) { - if (is_init(tsk)) + if (is_global_init(tsk)) return 1; if (tsk->ptrace & PT_PTRACED) return 0; @@ -373,13 +377,12 @@ static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, */ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) { - int signr = 0; + int signr; /* 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); @@ -407,9 +410,12 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) } } } - if (likely(tsk == current)) - recalc_sigpending(); - if (signr && unlikely(sig_kernel_stop(signr))) { + + recalc_sigpending(); + if (!signr) + return 0; + + if (unlikely(sig_kernel_stop(signr))) { /* * Set a marker that we have dequeued a stop signal. Our * caller might release the siglock and then the pending @@ -425,9 +431,7 @@ 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) && - ((info->si_code & __SI_MASK) == __SI_TIMER) && - info->si_sys_private){ + if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) { /* * Release the siglock to ensure proper locking order * of timer locks outside of siglocks. Note, we leave @@ -459,15 +463,15 @@ void signal_wake_up(struct task_struct *t, int resume) set_tsk_thread_flag(t, TIF_SIGPENDING); /* - * For SIGKILL, we want to wake it up in the stopped/traced case. - * We don't check t->state here because there is a race with it + * For SIGKILL, we want to wake it up in the stopped/traced/killable + * case. We don't check t->state here because there is a race with it * executing another processor and just now entering stopped state. * By using wake_up_state, we ensure the process will wake up and * handle its death signal. */ mask = TASK_INTERRUPTIBLE; if (resume) - mask |= TASK_STOPPED | TASK_TRACED; + mask |= TASK_WAKEKILL; if (!wake_up_state(t, mask)) kick_process(t); } @@ -529,22 +533,35 @@ static int rm_from_queue(unsigned long mask, struct sigpending *s) static int check_kill_permission(int sig, struct siginfo *info, struct task_struct *t) { - int error = -EINVAL; + struct pid *sid; + int error; + if (!valid_signal(sig)) - return error; + return -EINVAL; + + if (info != SEND_SIG_NOINFO && (is_si_special(info) || SI_FROMKERNEL(info))) + return 0; 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)) - return error; + if ((current->euid ^ t->suid) && (current->euid ^ t->uid) && + (current->uid ^ t->suid) && (current->uid ^ t->uid) && + !capable(CAP_KILL)) { + switch (sig) { + case SIGCONT: + sid = task_session(t); + /* + * We don't return the error if sid == NULL. The + * task was unhashed, the caller must notice this. + */ + if (!sid || sid == task_session(current)) + break; + default: + return -EPERM; + } + } return security_task_kill(t, info, sig, 0); } @@ -553,62 +570,44 @@ static int check_kill_permission(int sig, struct siginfo *info, static void do_notify_parent_cldstop(struct task_struct *tsk, int why); /* - * Handle magic process-wide effects of stop/continue signals. - * Unlike the signal actions, these happen immediately at signal-generation + * Handle magic process-wide effects of stop/continue signals. Unlike + * the signal actions, these happen immediately at signal-generation * time regardless of blocking, ignoring, or handling. This does the * actual continuing for SIGCONT, but not the actual stopping for stop - * signals. The process stop is done as a signal action for SIG_DFL. + * signals. The process stop is done as a signal action for SIG_DFL. + * + * Returns true if the signal should be actually delivered, otherwise + * it should be dropped. */ -static void handle_stop_signal(int sig, struct task_struct *p) +static int prepare_signal(int sig, struct task_struct *p) { + struct signal_struct *signal = p->signal; struct task_struct *t; - if (p->signal->flags & SIGNAL_GROUP_EXIT) + if (unlikely(signal->flags & SIGNAL_GROUP_EXIT)) { /* - * The process is in the middle of dying already. + * The process is in the middle of dying, nothing to do. */ - return; - - if (sig_kernel_stop(sig)) { + } else if (sig_kernel_stop(sig)) { /* * This is a stop signal. Remove SIGCONT from all queues. */ - rm_from_queue(sigmask(SIGCONT), &p->signal->shared_pending); + rm_from_queue(sigmask(SIGCONT), &signal->shared_pending); t = p; do { rm_from_queue(sigmask(SIGCONT), &t->pending); - t = next_thread(t); - } while (t != p); + } while_each_thread(p, t); } else if (sig == SIGCONT) { + unsigned int why; /* * Remove all stop signals from all queues, * and wake all threads. */ - if (unlikely(p->signal->group_stop_count > 0)) { - /* - * There was a group stop in progress. We'll - * pretend it finished before we got here. We are - * obliged to report it to the parent: if the - * SIGSTOP happened "after" this SIGCONT, then it - * would have cleared this pending SIGCONT. If it - * happened "before" this SIGCONT, then the parent - * got the SIGCHLD about the stop finishing before - * the continue happened. We do the notification - * now, and it's as if the stop had finished and - * the SIGCHLD was pending on entry to this kill. - */ - p->signal->group_stop_count = 0; - p->signal->flags = SIGNAL_STOP_CONTINUED; - spin_unlock(&p->sighand->siglock); - do_notify_parent_cldstop(p, CLD_STOPPED); - spin_lock(&p->sighand->siglock); - } - rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending); + rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending); t = p; do { unsigned int state; rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); - /* * If there is a handler for SIGCONT, we must make * sure that no thread returns to user mode before @@ -618,60 +617,174 @@ static void handle_stop_signal(int sig, struct task_struct *p) * running the handler. With the TIF_SIGPENDING * flag set, the thread will pause and acquire the * siglock that we hold now and until we've queued - * the pending signal. + * the pending signal. * * Wake up the stopped thread _after_ setting * TIF_SIGPENDING */ - state = TASK_STOPPED; + state = __TASK_STOPPED; if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) { set_tsk_thread_flag(t, TIF_SIGPENDING); state |= TASK_INTERRUPTIBLE; } wake_up_state(t, state); + } while_each_thread(p, t); - t = next_thread(t); - } while (t != p); + /* + * Notify the parent with CLD_CONTINUED if we were stopped. + * + * If we were in the middle of a group stop, we pretend it + * was already finished, and then continued. Since SIGCHLD + * doesn't queue we report only CLD_STOPPED, as if the next + * CLD_CONTINUED was dropped. + */ + why = 0; + if (signal->flags & SIGNAL_STOP_STOPPED) + why |= SIGNAL_CLD_CONTINUED; + else if (signal->group_stop_count) + why |= SIGNAL_CLD_STOPPED; - if (p->signal->flags & SIGNAL_STOP_STOPPED) { + if (why) { /* - * We were in fact stopped, and are now continued. - * Notify the parent with CLD_CONTINUED. + * The first thread which returns from finish_stop() + * will take ->siglock, notice SIGNAL_CLD_MASK, and + * notify its parent. See get_signal_to_deliver(). */ - p->signal->flags = SIGNAL_STOP_CONTINUED; - p->signal->group_exit_code = 0; - spin_unlock(&p->sighand->siglock); - do_notify_parent_cldstop(p, CLD_CONTINUED); - spin_lock(&p->sighand->siglock); + signal->flags = why | SIGNAL_STOP_CONTINUED; + signal->group_stop_count = 0; + signal->group_exit_code = 0; } else { /* * We are not stopped, but there could be a stop * signal in the middle of being processed after * being removed from the queue. Clear that too. */ - p->signal->flags = 0; + signal->flags &= ~SIGNAL_STOP_DEQUEUED; } - } else if (sig == SIGKILL) { + } + + return !sig_ignored(p, sig); +} + +/* + * Test if P wants to take SIG. After we've checked all threads with this, + * it's equivalent to finding no threads not blocking SIG. Any threads not + * blocking SIG were ruled out because they are not running and already + * have pending signals. Such threads will dequeue from the shared queue + * as soon as they're available, so putting the signal on the shared queue + * will be equivalent to sending it to one such thread. + */ +static inline int wants_signal(int sig, struct task_struct *p) +{ + if (sigismember(&p->blocked, sig)) + return 0; + if (p->flags & PF_EXITING) + return 0; + if (sig == SIGKILL) + return 1; + if (task_is_stopped_or_traced(p)) + return 0; + return task_curr(p) || !signal_pending(p); +} + +static void complete_signal(int sig, struct task_struct *p, int group) +{ + struct signal_struct *signal = p->signal; + struct task_struct *t; + + /* + * Now find a thread we can wake up to take the signal off the queue. + * + * If the main thread wants the signal, it gets first crack. + * Probably the least surprising to the average bear. + */ + if (wants_signal(sig, p)) + t = p; + else if (!group || thread_group_empty(p)) /* - * Make sure that any pending stop signal already dequeued - * is undone by the wakeup for SIGKILL. + * There is just one thread and it does not need to be woken. + * It will dequeue unblocked signals before it runs again. */ - p->signal->flags = 0; + return; + else { + /* + * Otherwise try to find a suitable thread. + */ + t = signal->curr_target; + while (!wants_signal(sig, t)) { + t = next_thread(t); + if (t == signal->curr_target) + /* + * No thread needs to be woken. + * Any eligible threads will see + * the signal in the queue soon. + */ + return; + } + signal->curr_target = t; } + + /* + * Found a killable thread. If the signal will be fatal, + * then start taking the whole group down immediately. + */ + if (sig_fatal(p, sig) && + !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) && + !sigismember(&t->real_blocked, sig) && + (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) { + /* + * This signal will be fatal to the whole group. + */ + if (!sig_kernel_coredump(sig)) { + /* + * Start a group exit and wake everybody up. + * This way we don't have other threads + * running and doing things after a slower + * thread has the fatal signal pending. + */ + signal->flags = SIGNAL_GROUP_EXIT; + signal->group_exit_code = sig; + signal->group_stop_count = 0; + t = p; + do { + sigaddset(&t->pending.signal, SIGKILL); + signal_wake_up(t, 1); + } while_each_thread(p, t); + return; + } + } + + /* + * The signal is already in the shared-pending queue. + * Tell the chosen thread to wake up and dequeue it. + */ + signal_wake_up(t, sig == SIGKILL); + return; +} + +static inline int legacy_queue(struct sigpending *signals, int sig) +{ + return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); } static int send_signal(int sig, struct siginfo *info, struct task_struct *t, - struct sigpending *signals) + int group) { - struct sigqueue * q = NULL; - int ret = 0; + struct sigpending *pending; + struct sigqueue *q; + + assert_spin_locked(&t->sighand->siglock); + if (!prepare_signal(sig, t)) + return 0; + pending = group ? &t->signal->shared_pending : &t->pending; /* - * Deliver the signal to listening signalfds. This must be called - * with the sighand lock held. + * Short-circuit ignored signals and support queuing + * exactly one non-rt signal, so that we can get more + * detailed information about the cause of the signal. */ - signalfd_notify(t, sig); - + if (legacy_queue(pending, sig)) + return 0; /* * fast-pathed signals for kernel-internal things like SIGSTOP * or SIGKILL. @@ -691,13 +804,13 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t, (is_si_special(info) || info->si_code >= 0))); if (q) { - list_add_tail(&q->list, &signals->list); + list_add_tail(&q->list, &pending->list); switch ((unsigned long) info) { case (unsigned long) SEND_SIG_NOINFO: q->info.si_signo = sig; q->info.si_errno = 0; q->info.si_code = SI_USER; - q->info.si_pid = current->pid; + q->info.si_pid = task_pid_vnr(current); q->info.si_uid = current->uid; break; case (unsigned long) SEND_SIG_PRIV: @@ -721,28 +834,27 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t, } out_set: - sigaddset(&signals->signal, sig); - return ret; + signalfd_notify(t, sig); + sigaddset(&pending->signal, sig); + complete_signal(sig, t, group); + return 0; } -#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); + current->comm, task_pid_nr(current), signr); -#ifdef __i386__ - printk("code at %08lx: ", regs->eip); +#if defined(__i386__) && !defined(__arch_um__) + printk("code at %08lx: ", regs->ip); { int i; for (i = 0; i < 16; i++) { unsigned char insn; - __get_user(insn, (unsigned char *)(regs->eip + i)); + __get_user(insn, (unsigned char *)(regs->ip + i)); printk("%02x ", insn); } } @@ -760,29 +872,16 @@ static int __init setup_print_fatal_signals(char *str) __setup("print-fatal-signals=", setup_print_fatal_signals); +int +__group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) +{ + return send_signal(sig, info, p, 1); +} + static int specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) { - int ret = 0; - - BUG_ON(!irqs_disabled()); - assert_spin_locked(&t->sighand->siglock); - - /* Short-circuit ignored signals. */ - if (sig_ignored(t, sig)) - goto out; - - /* Support queueing exactly one non-rt signal, so that we - can get more detailed information about the cause of - the signal. */ - if (LEGACY_QUEUE(&t->pending, sig)) - goto out; - - ret = send_signal(sig, info, t, &t->pending); - if (!ret && !sigismember(&t->blocked, sig)) - signal_wake_up(t, sig == SIGKILL); -out: - return ret; + return send_signal(sig, info, t, 0); } /* @@ -793,7 +892,8 @@ out: * since we do not want to have a signal handler that was blocked * be invoked when user space had explicitly blocked it. * - * We don't want to have recursive SIGSEGV's etc, for example. + * We don't want to have recursive SIGSEGV's etc, for example, + * that is why we also clear SIGNAL_UNKILLABLE. */ int force_sig_info(int sig, struct siginfo *info, struct task_struct *t) @@ -813,6 +913,8 @@ force_sig_info(int sig, struct siginfo *info, struct task_struct *t) recalc_sigpending_and_wake(t); } } + if (action->sa.sa_handler == SIG_DFL) + t->signal->flags &= ~SIGNAL_UNKILLABLE; ret = specific_send_sig_info(sig, info, t); spin_unlock_irqrestore(&t->sighand->siglock, flags); @@ -826,170 +928,14 @@ force_sig_specific(int sig, struct task_struct *t) } /* - * Test if P wants to take SIG. After we've checked all threads with this, - * it's equivalent to finding no threads not blocking SIG. Any threads not - * blocking SIG were ruled out because they are not running and already - * have pending signals. Such threads will dequeue from the shared queue - * as soon as they're available, so putting the signal on the shared queue - * will be equivalent to sending it to one such thread. - */ -static inline int wants_signal(int sig, struct task_struct *p) -{ - if (sigismember(&p->blocked, sig)) - return 0; - if (p->flags & PF_EXITING) - return 0; - if (sig == SIGKILL) - return 1; - if (p->state & (TASK_STOPPED | TASK_TRACED)) - return 0; - return task_curr(p) || !signal_pending(p); -} - -static void -__group_complete_signal(int sig, struct task_struct *p) -{ - struct task_struct *t; - - /* - * Now find a thread we can wake up to take the signal off the queue. - * - * If the main thread wants the signal, it gets first crack. - * Probably the least surprising to the average bear. - */ - if (wants_signal(sig, p)) - t = p; - else if (thread_group_empty(p)) - /* - * There is just one thread and it does not need to be woken. - * It will dequeue unblocked signals before it runs again. - */ - return; - else { - /* - * Otherwise try to find a suitable thread. - */ - t = p->signal->curr_target; - if (t == NULL) - /* restart balancing at this thread */ - t = p->signal->curr_target = p; - - while (!wants_signal(sig, t)) { - t = next_thread(t); - if (t == p->signal->curr_target) - /* - * No thread needs to be woken. - * Any eligible threads will see - * the signal in the queue soon. - */ - return; - } - p->signal->curr_target = t; - } - - /* - * Found a killable thread. If the signal will be fatal, - * then start taking the whole group down immediately. - */ - if (sig_fatal(p, sig) && !(p->signal->flags & SIGNAL_GROUP_EXIT) && - !sigismember(&t->real_blocked, sig) && - (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) { - /* - * This signal will be fatal to the whole group. - */ - if (!sig_kernel_coredump(sig)) { - /* - * Start a group exit and wake everybody up. - * This way we don't have other threads - * running and doing things after a slower - * thread has the fatal signal pending. - */ - p->signal->flags = SIGNAL_GROUP_EXIT; - p->signal->group_exit_code = sig; - p->signal->group_stop_count = 0; - t = p; - do { - sigaddset(&t->pending.signal, SIGKILL); - signal_wake_up(t, 1); - t = next_thread(t); - } while (t != p); - return; - } - - /* - * There will be a core dump. We make all threads other - * than the chosen one go into a group stop so that nothing - * happens until it gets scheduled, takes the signal off - * the shared queue, and does the core dump. This is a - * little more complicated than strictly necessary, but it - * keeps the signal state that winds up in the core dump - * unchanged from the death state, e.g. which thread had - * the core-dump signal unblocked. - */ - rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); - rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending); - p->signal->group_stop_count = 0; - p->signal->group_exit_task = t; - t = p; - do { - p->signal->group_stop_count++; - signal_wake_up(t, 0); - t = next_thread(t); - } while (t != p); - wake_up_process(p->signal->group_exit_task); - return; - } - - /* - * The signal is already in the shared-pending queue. - * Tell the chosen thread to wake up and dequeue it. - */ - signal_wake_up(t, sig == SIGKILL); - return; -} - -int -__group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) -{ - int ret = 0; - - assert_spin_locked(&p->sighand->siglock); - handle_stop_signal(sig, p); - - /* Short-circuit ignored signals. */ - if (sig_ignored(p, sig)) - return ret; - - if (LEGACY_QUEUE(&p->signal->shared_pending, sig)) - /* This is a non-RT signal and we already have one queued. */ - return ret; - - /* - * Put this signal on the shared-pending queue, or fail with EAGAIN. - * We always use the shared queue for process-wide signals, - * to avoid several races. - */ - ret = send_signal(sig, info, p, &p->signal->shared_pending); - if (unlikely(ret)) - return ret; - - __group_complete_signal(sig, p); - return 0; -} - -/* * Nuke all other threads in the group. */ void zap_other_threads(struct task_struct *p) { struct task_struct *t; - p->signal->flags = SIGNAL_GROUP_EXIT; p->signal->group_stop_count = 0; - if (thread_group_empty(p)) - return; - for (t = next_thread(p); t != p; t = next_thread(t)) { /* * Don't bother with already dead threads @@ -1003,13 +949,17 @@ void zap_other_threads(struct task_struct *p) } } -/* - * Must be called under rcu_read_lock() or with tasklist_lock read-held. - */ +int __fatal_signal_pending(struct task_struct *tsk) +{ + return sigismember(&tsk->pending.signal, SIGKILL); +} +EXPORT_SYMBOL(__fatal_signal_pending); + struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags) { struct sighand_struct *sighand; + rcu_read_lock(); for (;;) { sighand = rcu_dereference(tsk->sighand); if (unlikely(sighand == NULL)) @@ -1020,6 +970,7 @@ struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long break; spin_unlock_irqrestore(&sighand->siglock, *flags); } + rcu_read_unlock(); return sighand; } @@ -1043,7 +994,7 @@ int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) } /* - * kill_pgrp_info() sends a signal to a process group: this is what the tty + * __kill_pgrp_info() sends a signal to a process group: this is what the tty * control characters do (^C, ^Z etc) */ @@ -1062,34 +1013,27 @@ int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) return success ? 0 : retval; } -int kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) -{ - int retval; - - read_lock(&tasklist_lock); - retval = __kill_pgrp_info(sig, info, pgrp); - read_unlock(&tasklist_lock); - - return retval; -} - int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) { - int error; + int error = -ESRCH; struct task_struct *p; rcu_read_lock(); - if (unlikely(sig_needs_tasklist(sig))) - read_lock(&tasklist_lock); - +retry: p = pid_task(pid, PIDTYPE_PID); - error = -ESRCH; - if (p) + if (p) { error = group_send_sig_info(sig, info, p); - - if (unlikely(sig_needs_tasklist(sig))) - read_unlock(&tasklist_lock); + if (unlikely(error == -ESRCH)) + /* + * The task was unhashed in between, try again. + * If it is dead, pid_task() will return NULL, + * if we race with de_thread() it will find the + * new leader. + */ + goto retry; + } rcu_read_unlock(); + return error; } @@ -1098,7 +1042,7 @@ kill_proc_info(int sig, struct siginfo *info, pid_t pid) { int error; rcu_read_lock(); - error = kill_pid_info(sig, info, find_pid(pid)); + error = kill_pid_info(sig, info, find_vpid(pid)); rcu_read_unlock(); return error; } @@ -1150,30 +1094,34 @@ EXPORT_SYMBOL_GPL(kill_pid_info_as_uid); static int kill_something_info(int sig, struct siginfo *info, int pid) { int ret; - rcu_read_lock(); - if (!pid) { - ret = kill_pgrp_info(sig, info, task_pgrp(current)); - } else if (pid == -1) { + + if (pid > 0) { + rcu_read_lock(); + ret = kill_pid_info(sig, info, find_vpid(pid)); + rcu_read_unlock(); + return ret; + } + + read_lock(&tasklist_lock); + if (pid != -1) { + ret = __kill_pgrp_info(sig, info, + pid ? find_vpid(-pid) : task_pgrp(current)); + } else { int retval = 0, count = 0; struct task_struct * p; - read_lock(&tasklist_lock); for_each_process(p) { - if (p->pid > 1 && p->tgid != current->tgid) { + if (p->pid > 1 && !same_thread_group(p, current)) { int err = group_send_sig_info(sig, info, p); ++count; if (err != -EPERM) retval = err; } } - read_unlock(&tasklist_lock); ret = count ? retval : -ESRCH; - } else if (pid < 0) { - ret = kill_pgrp_info(sig, info, find_pid(-pid)); - } else { - ret = kill_pid_info(sig, info, find_pid(pid)); } - rcu_read_unlock(); + read_unlock(&tasklist_lock); + return ret; } @@ -1182,8 +1130,7 @@ static int kill_something_info(int sig, struct siginfo *info, int pid) */ /* - * These two are the most common entry points. They send a signal - * just to the specific thread. + * The caller must ensure the task can't exit. */ int send_sig_info(int sig, struct siginfo *info, struct task_struct *p) @@ -1198,17 +1145,9 @@ send_sig_info(int sig, struct siginfo *info, struct task_struct *p) if (!valid_signal(sig)) return -EINVAL; - /* - * We need the tasklist lock even for the specific - * thread case (when we don't need to follow the group - * lists) in order to avoid races with "p->sighand" - * going away or changing from under us. - */ - read_lock(&tasklist_lock); spin_lock_irqsave(&p->sighand->siglock, flags); ret = specific_send_sig_info(sig, info, p); spin_unlock_irqrestore(&p->sighand->siglock, flags); - read_unlock(&tasklist_lock); return ret; } @@ -1221,20 +1160,6 @@ send_sig(int sig, struct task_struct *p, int priv) return send_sig_info(sig, __si_special(priv), p); } -/* - * This is the entry point for "process-wide" signals. - * They will go to an appropriate thread in the thread group. - */ -int -send_group_sig_info(int sig, struct siginfo *info, struct task_struct *p) -{ - int ret; - read_lock(&tasklist_lock); - ret = group_send_sig_info(sig, info, p); - read_unlock(&tasklist_lock); - return ret; -} - void force_sig(int sig, struct task_struct *p) { @@ -1262,7 +1187,13 @@ force_sigsegv(int sig, struct task_struct *p) int kill_pgrp(struct pid *pid, int sig, int priv) { - return kill_pgrp_info(sig, __si_special(priv), pid); + int ret; + + read_lock(&tasklist_lock); + ret = __kill_pgrp_info(sig, __si_special(priv), pid); + read_unlock(&tasklist_lock); + + return ret; } EXPORT_SYMBOL(kill_pgrp); @@ -1275,7 +1206,12 @@ EXPORT_SYMBOL(kill_pid); int kill_proc(pid_t pid, int sig, int priv) { - return kill_proc_info(sig, __si_special(priv), pid); + int ret; + + rcu_read_lock(); + ret = kill_pid_info(sig, __si_special(priv), find_pid(pid)); + rcu_read_unlock(); + return ret; } /* @@ -1317,28 +1253,24 @@ void sigqueue_free(struct sigqueue *q) __sigqueue_free(q); } -int send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) +int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) { + int sig = q->info.si_signo; + struct sigpending *pending; unsigned long flags; - int ret = 0; + int ret; BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); - /* - * The rcu based delayed sighand destroy makes it possible to - * run this without tasklist lock held. The task struct itself - * cannot go away as create_timer did get_task_struct(). - * - * We return -1, when the task is marked exiting, so - * posix_timer_event can redirect it to the group leader - */ - rcu_read_lock(); + ret = -1; + if (!likely(lock_task_sighand(t, &flags))) + goto ret; - if (!likely(lock_task_sighand(p, &flags))) { - ret = -1; - goto out_err; - } + ret = 1; /* the signal is ignored */ + if (!prepare_signal(sig, t)) + goto out; + ret = 0; if (unlikely(!list_empty(&q->list))) { /* * If an SI_TIMER entry is already queue just increment @@ -1348,77 +1280,15 @@ int send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) q->info.si_overrun++; goto out; } - /* Short-circuit ignored signals. */ - if (sig_ignored(p, sig)) { - ret = 1; - goto out; - } - /* - * Deliver the signal to listening signalfds. This must be called - * with the sighand lock held. - */ - signalfd_notify(p, sig); - - list_add_tail(&q->list, &p->pending.list); - sigaddset(&p->pending.signal, sig); - if (!sigismember(&p->blocked, sig)) - signal_wake_up(p, sig == SIGKILL); - -out: - unlock_task_sighand(p, &flags); -out_err: - rcu_read_unlock(); - return ret; -} - -int -send_group_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) -{ - unsigned long flags; - int ret = 0; - - BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); - - read_lock(&tasklist_lock); - /* Since it_lock is held, p->sighand cannot be NULL. */ - spin_lock_irqsave(&p->sighand->siglock, flags); - handle_stop_signal(sig, p); - - /* Short-circuit ignored signals. */ - if (sig_ignored(p, sig)) { - ret = 1; - goto out; - } - - if (unlikely(!list_empty(&q->list))) { - /* - * If an SI_TIMER entry is already queue just increment - * the overrun count. Other uses should not try to - * send the signal multiple times. - */ - BUG_ON(q->info.si_code != SI_TIMER); - q->info.si_overrun++; - goto out; - } - /* - * Deliver the signal to listening signalfds. This must be called - * with the sighand lock held. - */ - signalfd_notify(p, sig); - - /* - * Put this signal on the shared-pending queue. - * We always use the shared queue for process-wide signals, - * to avoid several races. - */ - list_add_tail(&q->list, &p->signal->shared_pending.list); - sigaddset(&p->signal->shared_pending.signal, sig); - - __group_complete_signal(sig, p); + signalfd_notify(t, sig); + pending = group ? &t->signal->shared_pending : &t->pending; + list_add_tail(&q->list, &pending->list); + sigaddset(&pending->signal, sig); + complete_signal(sig, t, group); out: - spin_unlock_irqrestore(&p->sighand->siglock, flags); - read_unlock(&tasklist_lock); + unlock_task_sighand(t, &flags); +ret: return ret; } @@ -1445,14 +1315,29 @@ void do_notify_parent(struct task_struct *tsk, int sig) BUG_ON(sig == -1); /* do_notify_parent_cldstop should have been called instead. */ - BUG_ON(tsk->state & (TASK_STOPPED|TASK_TRACED)); + BUG_ON(task_is_stopped_or_traced(tsk)); BUG_ON(!tsk->ptrace && (tsk->group_leader != tsk || !thread_group_empty(tsk))); info.si_signo = sig; info.si_errno = 0; - info.si_pid = tsk->pid; + /* + * we are under tasklist_lock here so our parent is tied to + * us and cannot exit and release its namespace. + * + * the only it can is to switch its nsproxy with sys_unshare, + * bu uncharing pid namespaces is not allowed, so we'll always + * see relevant namespace + * + * write_lock() currently calls preempt_disable() which is the + * same as rcu_read_lock(), but according to Oleg, this is not + * correct to rely on this + */ + rcu_read_lock(); + info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); + rcu_read_unlock(); + info.si_uid = tsk->uid; /* FIXME: find out whether or not this is supposed to be c*time. */ @@ -1517,7 +1402,13 @@ static void do_notify_parent_cldstop(struct task_struct *tsk, int why) info.si_signo = SIGCHLD; info.si_errno = 0; - info.si_pid = tsk->pid; + /* + * see comment in do_notify_parent() abot the following 3 lines + */ + rcu_read_lock(); + info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); + rcu_read_unlock(); + info.si_uid = tsk->uid; /* FIXME: find out whether or not this is supposed to be c*time. */ @@ -1555,11 +1446,6 @@ static inline int may_ptrace_stop(void) { if (!likely(current->ptrace & PT_PTRACED)) return 0; - - if (unlikely(current->parent == current->real_parent && - (current->ptrace & PT_ATTACHED))) - return 0; - /* * Are we in the middle of do_coredump? * If so and our tracer is also part of the coredump stopping @@ -1577,6 +1463,17 @@ static inline int may_ptrace_stop(void) } /* + * Return nonzero if there is a SIGKILL that should be waking us up. + * Called with the siglock held. + */ +static int sigkill_pending(struct task_struct *tsk) +{ + return ((sigismember(&tsk->pending.signal, SIGKILL) || + sigismember(&tsk->signal->shared_pending.signal, SIGKILL)) && + !unlikely(sigismember(&tsk->blocked, SIGKILL))); +} + +/* * This must be called with current->sighand->siglock held. * * This should be the path for all ptrace stops. @@ -1584,11 +1481,31 @@ static inline int may_ptrace_stop(void) * That makes it a way to test a stopped process for * being ptrace-stopped vs being job-control-stopped. * - * If we actually decide not to stop at all because the tracer is gone, - * we leave nostop_code in current->exit_code. + * If we actually decide not to stop at all because the tracer + * is gone, we keep current->exit_code unless clear_code. */ -static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info) +static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info) { + int killed = 0; + + if (arch_ptrace_stop_needed(exit_code, info)) { + /* + * The arch code has something special to do before a + * ptrace stop. This is allowed to block, e.g. for faults + * on user stack pages. We can't keep the siglock while + * calling arch_ptrace_stop, so we must release it now. + * To preserve proper semantics, we must do this before + * any signal bookkeeping like checking group_stop_count. + * Meanwhile, a SIGKILL could come in before we retake the + * siglock. That must prevent us from sleeping in TASK_TRACED. + * So after regaining the lock, we must check for SIGKILL. + */ + spin_unlock_irq(¤t->sighand->siglock); + arch_ptrace_stop(exit_code, info); + spin_lock_irq(¤t->sighand->siglock); + killed = sigkill_pending(current); + } + /* * If there is a group stop in progress, * we must participate in the bookkeeping. @@ -1600,25 +1517,32 @@ static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info) current->exit_code = exit_code; /* Let the debugger run. */ - set_current_state(TASK_TRACED); + __set_current_state(TASK_TRACED); spin_unlock_irq(¤t->sighand->siglock); - try_to_freeze(); read_lock(&tasklist_lock); - if (may_ptrace_stop()) { + if (!unlikely(killed) && may_ptrace_stop()) { do_notify_parent_cldstop(current, CLD_TRAPPED); read_unlock(&tasklist_lock); schedule(); } else { /* * By the time we got the lock, our tracer went away. - * Don't stop here. + * Don't drop the lock yet, another tracer may come. */ + __set_current_state(TASK_RUNNING); + if (clear_code) + current->exit_code = 0; read_unlock(&tasklist_lock); - set_current_state(TASK_RUNNING); - current->exit_code = nostop_code; } /* + * While in TASK_TRACED, we were considered "frozen enough". + * Now that we woke up, it's crucial if we're supposed to be + * frozen that we freeze now before running anything substantial. + */ + try_to_freeze(); + + /* * We are back. Now reacquire the siglock before touching * last_siginfo, so that we are sure to have synchronized with * any signal-sending on another CPU that wants to examine it. @@ -1643,12 +1567,12 @@ void ptrace_notify(int exit_code) memset(&info, 0, sizeof info); info.si_signo = SIGTRAP; info.si_code = exit_code; - info.si_pid = current->pid; + info.si_pid = task_pid_vnr(current); info.si_uid = current->uid; /* Let the debugger run. */ spin_lock_irq(¤t->sighand->siglock); - ptrace_stop(exit_code, 0, &info); + ptrace_stop(exit_code, 1, &info); spin_unlock_irq(¤t->sighand->siglock); } @@ -1686,9 +1610,6 @@ static int do_signal_stop(int signr) struct signal_struct *sig = current->signal; int stop_count; - if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED)) - return 0; - if (sig->group_stop_count > 0) { /* * There is a group stop in progress. We don't need to @@ -1696,12 +1617,16 @@ static int do_signal_stop(int signr) */ stop_count = --sig->group_stop_count; } else { + struct task_struct *t; + + if (unlikely((sig->flags & (SIGNAL_STOP_DEQUEUED | SIGNAL_UNKILLABLE)) + != SIGNAL_STOP_DEQUEUED) || + unlikely(signal_group_exit(sig))) + return 0; /* * There is no group stop already in progress. * We must initiate one now. */ - struct task_struct *t; - sig->group_exit_code = signr; stop_count = 0; @@ -1711,8 +1636,8 @@ static int do_signal_stop(int signr) * stop is always done with the siglock held, * so this check has no races. */ - if (!t->exit_state && - !(t->state & (TASK_STOPPED|TASK_TRACED))) { + if (!(t->flags & PF_EXITING) && + !task_is_stopped_or_traced(t)) { stop_count++; signal_wake_up(t, 0); } @@ -1729,102 +1654,97 @@ static int do_signal_stop(int signr) return 1; } -/* - * Do appropriate magic when group_stop_count > 0. - * We return nonzero if we stopped, after releasing the siglock. - * We return zero if we still hold the siglock and should look - * for another signal without checking group_stop_count again. - */ -static int handle_group_stop(void) +static int ptrace_signal(int signr, siginfo_t *info, + struct pt_regs *regs, void *cookie) { - int stop_count; + if (!(current->ptrace & PT_PTRACED)) + return signr; - if (current->signal->group_exit_task == current) { - /* - * Group stop is so we can do a core dump, - * We are the initiating thread, so get on with it. - */ - current->signal->group_exit_task = NULL; - return 0; + ptrace_signal_deliver(regs, cookie); + + /* Let the debugger run. */ + ptrace_stop(signr, 0, info); + + /* We're back. Did the debugger cancel the sig? */ + signr = current->exit_code; + if (signr == 0) + return signr; + + current->exit_code = 0; + + /* Update the siginfo structure if the signal has + changed. If the debugger wanted something + specific in the siginfo structure then it should + have updated *info via PTRACE_SETSIGINFO. */ + if (signr != info->si_signo) { + info->si_signo = signr; + info->si_errno = 0; + info->si_code = SI_USER; + info->si_pid = task_pid_vnr(current->parent); + info->si_uid = current->parent->uid; } - if (current->signal->flags & SIGNAL_GROUP_EXIT) - /* - * Group stop is so another thread can do a core dump, - * or else we are racing against a death signal. - * Just punt the stop so we can get the next signal. - */ - return 0; + /* If the (new) signal is now blocked, requeue it. */ + if (sigismember(¤t->blocked, signr)) { + specific_send_sig_info(signr, info, current); + signr = 0; + } - /* - * There is a group stop in progress. We stop - * without any associated signal being in our queue. - */ - stop_count = --current->signal->group_stop_count; - if (stop_count == 0) - current->signal->flags = SIGNAL_STOP_STOPPED; - current->exit_code = current->signal->group_exit_code; - set_current_state(TASK_STOPPED); - spin_unlock_irq(¤t->sighand->siglock); - finish_stop(stop_count); - return 1; + return signr; } int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, struct pt_regs *regs, void *cookie) { - sigset_t *mask = ¤t->blocked; - int signr = 0; + struct sighand_struct *sighand = current->sighand; + struct signal_struct *signal = current->signal; + int signr; +relock: + /* + * We'll jump back here after any time we were stopped in TASK_STOPPED. + * While in TASK_STOPPED, we were considered "frozen enough". + * Now that we woke up, it's crucial if we're supposed to be + * frozen that we freeze now before running anything substantial. + */ try_to_freeze(); -relock: - spin_lock_irq(¤t->sighand->siglock); + spin_lock_irq(&sighand->siglock); + /* + * Every stopped thread goes here after wakeup. Check to see if + * we should notify the parent, prepare_signal(SIGCONT) encodes + * the CLD_ si_code into SIGNAL_CLD_MASK bits. + */ + if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { + int why = (signal->flags & SIGNAL_STOP_CONTINUED) + ? CLD_CONTINUED : CLD_STOPPED; + signal->flags &= ~SIGNAL_CLD_MASK; + spin_unlock_irq(&sighand->siglock); + + read_lock(&tasklist_lock); + do_notify_parent_cldstop(current->group_leader, why); + read_unlock(&tasklist_lock); + goto relock; + } + for (;;) { struct k_sigaction *ka; - if (unlikely(current->signal->group_stop_count > 0) && - handle_group_stop()) + if (unlikely(signal->group_stop_count > 0) && + do_signal_stop(0)) goto relock; - signr = dequeue_signal(current, mask, info); - + signr = dequeue_signal(current, ¤t->blocked, info); if (!signr) break; /* will return 0 */ - if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) { - ptrace_signal_deliver(regs, cookie); - - /* Let the debugger run. */ - ptrace_stop(signr, signr, info); - - /* We're back. Did the debugger cancel the sig? */ - signr = current->exit_code; - if (signr == 0) - continue; - - current->exit_code = 0; - - /* Update the siginfo structure if the signal has - changed. If the debugger wanted something - specific in the siginfo structure then it should - have updated *info via PTRACE_SETSIGINFO. */ - if (signr != info->si_signo) { - info->si_signo = signr; - info->si_errno = 0; - info->si_code = SI_USER; - info->si_pid = current->parent->pid; - info->si_uid = current->parent->uid; - } - - /* If the (new) signal is now blocked, requeue it. */ - if (sigismember(¤t->blocked, signr)) { - specific_send_sig_info(signr, info, current); + if (signr != SIGKILL) { + signr = ptrace_signal(signr, info, regs, cookie); + if (!signr) continue; - } } - ka = ¤t->sighand->action[signr-1]; + ka = &sighand->action[signr-1]; if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ continue; if (ka->sa.sa_handler != SIG_DFL) { @@ -1844,11 +1764,10 @@ relock: continue; /* - * Init of a pid space gets no signals it doesn't want from - * within that pid space. It can of course get signals from - * its parent pid space. + * Global init gets no signals it doesn't want. */ - if (current == child_reaper(current)) + if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && + !signal_group_exit(signal)) continue; if (sig_kernel_stop(signr)) { @@ -1863,14 +1782,14 @@ relock: * We need to check for that and bail out if necessary. */ if (signr != SIGSTOP) { - spin_unlock_irq(¤t->sighand->siglock); + spin_unlock_irq(&sighand->siglock); /* signals can be posted during this window */ if (is_current_pgrp_orphaned()) goto relock; - spin_lock_irq(¤t->sighand->siglock); + spin_lock_irq(&sighand->siglock); } if (likely(do_signal_stop(signr))) { @@ -1885,15 +1804,16 @@ relock: continue; } - spin_unlock_irq(¤t->sighand->siglock); + spin_unlock_irq(&sighand->siglock); /* * 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 (print_fatal_signals) + print_fatal_signal(regs, signr); /* * If it was able to dump core, this kills all * other threads in the group and synchronizes with @@ -1911,10 +1831,52 @@ relock: do_group_exit(signr); /* NOTREACHED */ } - spin_unlock_irq(¤t->sighand->siglock); + spin_unlock_irq(&sighand->siglock); return signr; } +void exit_signals(struct task_struct *tsk) +{ + int group_stop = 0; + struct task_struct *t; + + if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { + tsk->flags |= PF_EXITING; + return; + } + + spin_lock_irq(&tsk->sighand->siglock); + /* + * From now this task is not visible for group-wide signals, + * see wants_signal(), do_signal_stop(). + */ + tsk->flags |= PF_EXITING; + if (!signal_pending(tsk)) + goto out; + + /* It could be that __group_complete_signal() choose us to + * notify about group-wide signal. Another thread should be + * woken now to take the signal since we will not. + */ + for (t = tsk; (t = next_thread(t)) != tsk; ) + if (!signal_pending(t) && !(t->flags & PF_EXITING)) + recalc_sigpending_and_wake(t); + + if (unlikely(tsk->signal->group_stop_count) && + !--tsk->signal->group_stop_count) { + tsk->signal->flags = SIGNAL_STOP_STOPPED; + group_stop = 1; + } +out: + spin_unlock_irq(&tsk->sighand->siglock); + + if (unlikely(group_stop)) { + read_lock(&tasklist_lock); + do_notify_parent_cldstop(tsk, CLD_STOPPED); + read_unlock(&tasklist_lock); + } +} + EXPORT_SYMBOL(recalc_sigpending); EXPORT_SYMBOL_GPL(dequeue_signal); EXPORT_SYMBOL(flush_signals); @@ -2202,7 +2164,7 @@ sys_kill(int pid, int sig) info.si_signo = sig; info.si_errno = 0; info.si_code = SI_USER; - info.si_pid = current->tgid; + info.si_pid = task_tgid_vnr(current); info.si_uid = current->uid; return kill_something_info(sig, &info, pid); @@ -2213,30 +2175,33 @@ static int do_tkill(int tgid, int pid, int sig) int error; struct siginfo info; struct task_struct *p; + unsigned long flags; error = -ESRCH; info.si_signo = sig; info.si_errno = 0; info.si_code = SI_TKILL; - info.si_pid = current->tgid; + info.si_pid = task_tgid_vnr(current); info.si_uid = current->uid; - read_lock(&tasklist_lock); - p = find_task_by_pid(pid); - if (p && (tgid <= 0 || p->tgid == tgid)) { + rcu_read_lock(); + p = find_task_by_vpid(pid); + if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { error = check_kill_permission(sig, &info, p); /* * The null signal is a permissions and process existence * probe. No signal is actually delivered. + * + * If lock_task_sighand() fails we pretend the task dies + * after receiving the signal. The window is tiny, and the + * signal is private anyway. */ - if (!error && sig && p->sighand) { - spin_lock_irq(&p->sighand->siglock); - handle_stop_signal(sig, p); + if (!error && sig && lock_task_sighand(p, &flags)) { error = specific_send_sig_info(sig, &info, p); - spin_unlock_irq(&p->sighand->siglock); + unlock_task_sighand(p, &flags); } } - read_unlock(&tasklist_lock); + rcu_read_unlock(); return error; } @@ -2293,24 +2258,16 @@ sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo) int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) { + struct task_struct *t = current; struct k_sigaction *k; sigset_t mask; if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) return -EINVAL; - k = ¤t->sighand->action[sig-1]; + k = &t->sighand->action[sig-1]; spin_lock_irq(¤t->sighand->siglock); - if (signal_pending(current)) { - /* - * If there might be a fatal signal pending on multiple - * threads, make sure we take it before changing the action. - */ - spin_unlock_irq(¤t->sighand->siglock); - return -ERESTARTNOINTR; - } - if (oact) *oact = *k; @@ -2329,15 +2286,12 @@ int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) * (for example, SIGCHLD), shall cause the pending signal to * be discarded, whether or not it is blocked" */ - if (act->sa.sa_handler == SIG_IGN || - (act->sa.sa_handler == SIG_DFL && sig_kernel_ignore(sig))) { - struct task_struct *t = current; + if (__sig_ignored(t, sig)) { sigemptyset(&mask); sigaddset(&mask, sig); rm_from_queue_full(&mask, &t->signal->shared_pending); do { rm_from_queue_full(&mask, &t->pending); - recalc_sigpending_and_wake(t); t = next_thread(t); } while (t != current); } @@ -2587,7 +2541,7 @@ asmlinkage long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize) current->state = TASK_INTERRUPTIBLE; schedule(); - set_thread_flag(TIF_RESTORE_SIGMASK); + set_restore_sigmask(); return -ERESTARTNOHAND; } #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */