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| author | Oleg Nesterov <oleg@tv-sign.ru> | 2007-08-22 14:01:37 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-08-22 19:52:46 -0700 |
| commit | d02479bdeb1c9b037892061cdcf4e730183391fa (patch) | |
| tree | 1268f3dcf973f8fc3d86c84d9b09ff9048647491 /kernel | |
| parent | 179394af7a2baa1d0a3cb1670075310d72247d38 (diff) | |
| download | linux-d02479bdeb1c9b037892061cdcf4e730183391fa.tar.gz linux-d02479bdeb1c9b037892061cdcf4e730183391fa.tar.bz2 linux-d02479bdeb1c9b037892061cdcf4e730183391fa.zip | |
posix-timers: fix creation race
sys_timer_create() sets ->it_process and unlocks ->siglock, then checks
tmr->it_sigev_notify to define if get_task_struct() is needed.
We already passed ->it_id to the caller, another thread can delete this timer
and free its memory in between.
As a minimal fix, move this code under ->siglock, sys_timer_delete() takes it
too before calling release_posix_timer(). A proper serialization would be to
take ->it_lock, we add a partly initialized timer on posix_timers_id, not
good.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/posix-timers.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c index 6923ad8a5983..7a15afb73ed0 100644 --- a/kernel/posix-timers.c +++ b/kernel/posix-timers.c @@ -547,9 +547,9 @@ sys_timer_create(const clockid_t which_clock, new_timer->it_process = process; list_add(&new_timer->list, &process->signal->posix_timers); - spin_unlock_irqrestore(&process->sighand->siglock, flags); if (new_timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID)) get_task_struct(process); + spin_unlock_irqrestore(&process->sighand->siglock, flags); } else { spin_unlock_irqrestore(&process->sighand->siglock, flags); process = NULL; |