From 188a1eafa03aaa5e5fe6f53e637e704cd2c31c7c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Fri, 23 Sep 2005 13:22:21 -0700 Subject: Make sure SIGKILL gets proper respect Bhavesh P. Davda noticed that SIGKILL wouldn't properly kill a process under just the right cicumstances: a stopped task that already had another signal queued would get the SIGKILL queued onto the shared queue, and there it would remain until SIGCONT. This simplifies the signal acceptance logic, and fixes the bug in the process. Losely based on an earlier patch by Bhavesh. Signed-off-by: Linus Torvalds --- kernel/signal.c | 31 ++++++++++++++----------------- 1 file changed, 14 insertions(+), 17 deletions(-) (limited to 'kernel') diff --git a/kernel/signal.c b/kernel/signal.c index b92c3c9f8b9a..5a274705ba19 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -936,34 +936,31 @@ force_sig_specific(int sig, struct task_struct *t) * as soon as they're available, so putting the signal on the shared queue * will be equivalent to sending it to one such thread. */ -#define wants_signal(sig, p, mask) \ - (!sigismember(&(p)->blocked, sig) \ - && !((p)->state & mask) \ - && !((p)->flags & PF_EXITING) \ - && (task_curr(p) || !signal_pending(p))) - +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) { - unsigned int mask; struct task_struct *t; - /* - * Don't bother traced and stopped tasks (but - * SIGKILL will punch through that). - */ - mask = TASK_STOPPED | TASK_TRACED; - if (sig == SIGKILL) - mask = 0; - /* * 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, mask)) + if (wants_signal(sig, p)) t = p; else if (thread_group_empty(p)) /* @@ -981,7 +978,7 @@ __group_complete_signal(int sig, struct task_struct *p) t = p->signal->curr_target = p; BUG_ON(t->tgid != p->tgid); - while (!wants_signal(sig, t, mask)) { + while (!wants_signal(sig, t)) { t = next_thread(t); if (t == p->signal->curr_target) /* -- cgit v1.2.1