diff options
Diffstat (limited to 'kernel/signal.c')
| -rw-r--r-- | kernel/signal.c | 110 |
1 files changed, 55 insertions, 55 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index 8a04869..3670225 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -456,26 +456,50 @@ 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 = __dequeue_signal(&tsk->pending, mask, info); - if (!signr) + if (!signr) { signr = __dequeue_signal(&tsk->signal->shared_pending, mask, info); + /* + * itimer signal ? + * + * itimers are process shared and we restart periodic + * itimers in the signal delivery path to prevent DoS + * attacks in the high resolution timer case. This is + * compliant with the old way of self restarting + * itimers, as the SIGALRM is a legacy signal and only + * queued once. Changing the restart behaviour to + * restart the timer in the signal dequeue path is + * reducing the timer noise on heavy loaded !highres + * systems too. + */ + if (unlikely(signr == SIGALRM)) { + struct hrtimer *tmr = &tsk->signal->real_timer; + + if (!hrtimer_is_queued(tmr) && + tsk->signal->it_real_incr.tv64 != 0) { + hrtimer_forward(tmr, tmr->base->get_time(), + tsk->signal->it_real_incr); + hrtimer_restart(tmr); + } + } + } recalc_sigpending_tsk(tsk); - if (signr && 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 - * stop signal it is about to process is no longer in the - * pending bitmasks, but must still be cleared by a SIGCONT - * (and overruled by a SIGKILL). So those cases clear this - * shared flag after we've set it. Note that this flag may - * remain set after the signal we return is ignored or - * handled. That doesn't matter because its only purpose - * is to alert stop-signal processing code when another - * processor has come along and cleared the flag. - */ - if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) - tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; - } + if (signr && 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 + * stop signal it is about to process is no longer in the + * pending bitmasks, but must still be cleared by a SIGCONT + * (and overruled by a SIGKILL). So those cases clear this + * shared flag after we've set it. Note that this flag may + * remain set after the signal we return is ignored or + * handled. That doesn't matter because its only purpose + * is to alert stop-signal processing code when another + * processor has come along and cleared the flag. + */ + if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) + tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; + } if ( signr && ((info->si_code & __SI_MASK) == __SI_TIMER) && info->si_sys_private){ @@ -1096,42 +1120,21 @@ int kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) return retval; } -int __kill_pg_info(int sig, struct siginfo *info, pid_t pgrp) -{ - if (pgrp <= 0) - return -EINVAL; - - return __kill_pgrp_info(sig, info, find_pid(pgrp)); -} - -int -kill_pg_info(int sig, struct siginfo *info, pid_t pgrp) -{ - int retval; - - read_lock(&tasklist_lock); - retval = __kill_pg_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 acquired_tasklist_lock = 0; struct task_struct *p; rcu_read_lock(); - if (unlikely(sig_needs_tasklist(sig))) { + if (unlikely(sig_needs_tasklist(sig))) read_lock(&tasklist_lock); - acquired_tasklist_lock = 1; - } + p = pid_task(pid, PIDTYPE_PID); error = -ESRCH; if (p) error = group_send_sig_info(sig, info, p); - if (unlikely(acquired_tasklist_lock)) + + if (unlikely(sig_needs_tasklist(sig))) read_unlock(&tasklist_lock); rcu_read_unlock(); return error; @@ -1193,8 +1196,10 @@ 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) { - return kill_pg_info(sig, info, process_group(current)); + ret = kill_pgrp_info(sig, info, task_pgrp(current)); } else if (pid == -1) { int retval = 0, count = 0; struct task_struct * p; @@ -1209,12 +1214,14 @@ static int kill_something_info(int sig, struct siginfo *info, int pid) } } read_unlock(&tasklist_lock); - return count ? retval : -ESRCH; + ret = count ? retval : -ESRCH; } else if (pid < 0) { - return kill_pg_info(sig, info, -pid); + ret = kill_pgrp_info(sig, info, find_pid(-pid)); } else { - return kill_proc_info(sig, info, pid); + ret = kill_pid_info(sig, info, find_pid(pid)); } + rcu_read_unlock(); + return ret; } /* @@ -1313,12 +1320,6 @@ int kill_pid(struct pid *pid, int sig, int priv) EXPORT_SYMBOL(kill_pid); int -kill_pg(pid_t pgrp, int sig, int priv) -{ - return kill_pg_info(sig, __si_special(priv), pgrp); -} - -int kill_proc(pid_t pid, int sig, int priv) { return kill_proc_info(sig, __si_special(priv), pid); @@ -1907,7 +1908,7 @@ relock: /* signals can be posted during this window */ - if (is_orphaned_pgrp(process_group(current))) + if (is_current_pgrp_orphaned()) goto relock; spin_lock_irq(¤t->sighand->siglock); @@ -1957,7 +1958,6 @@ EXPORT_SYMBOL(recalc_sigpending); EXPORT_SYMBOL_GPL(dequeue_signal); EXPORT_SYMBOL(flush_signals); EXPORT_SYMBOL(force_sig); -EXPORT_SYMBOL(kill_pg); EXPORT_SYMBOL(kill_proc); EXPORT_SYMBOL(ptrace_notify); EXPORT_SYMBOL(send_sig); @@ -2284,7 +2284,7 @@ static int do_tkill(int tgid, int pid, int sig) * @pid: the PID of the thread * @sig: signal to be sent * - * This syscall also checks the tgid and returns -ESRCH even if the PID + * This syscall also checks the @tgid and returns -ESRCH even if the PID * exists but it's not belonging to the target process anymore. This * method solves the problem of threads exiting and PIDs getting reused. */ |
