diff options
| author | Jeremy Kerr <jeremy@redfishsoftware.com.au> | 2004-06-01 17:18:12 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2004-06-01 17:18:12 -0700 |
| commit | 651bea8c072b9ab412719f69a5e76bc91f3124cc (patch) | |
| tree | a1dd8804b285848ac5f85b695339ab09bf5242a8 /kernel | |
| parent | 8012a7f767b59fca384aad773b0cd87ccecc6ad9 (diff) | |
| download | history-651bea8c072b9ab412719f69a5e76bc91f3124cc.tar.gz | |
[PATCH] Fix signal race during process exit
Fix a race identified by Jeremy Kerr <jeremy@redfishsoftware.com.au>: if
update_process_times() decides to deliver a signal due to process timer
expiry, it can race with __exit_sighand()'s freeing of task->sighand.
Fix that by clearing the per-process timer state in exit_notify(), while under
local_irq_disable() and under tasklist_lock. tasklist_lock provides exclusion
wrt release_task()'s freeing of task->sighand and local_irq_disable() provides
exclusion wrt update_process_times()'s inspection of the per-process timer
state.
We also need to deal with the send_sig() calls in do_process_times() by
setting rlim_cur to RLIM_INFINITY.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/exit.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 8c1a599db266e1..0be17fec85fe44 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -737,6 +737,14 @@ static void exit_notify(struct task_struct *tsk) tsk->flags |= PF_DEAD; /* + * Clear these here so that update_process_times() won't try to deliver + * itimer, profile or rlimit signals to this task while it is in late exit. + */ + tsk->it_virt_incr = 0; + tsk->it_prof_value = 0; + tsk->rlim[RLIMIT_CPU].rlim_cur = RLIM_INFINITY; + + /* * In the preemption case it must be impossible for the task * to get runnable again, so use "_raw_" unlock to keep * preempt_count elevated until we schedule(). |