diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2007-08-22 14:01:37 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-08-22 19:52:45 -0700 |
commit | 179394af7a2baa1d0a3cb1670075310d72247d38 (patch) | |
tree | f15d4ad366b1bfa7787d6a6a809816f507c4a23a /include/linux/in6.h | |
parent | 928923c76b393e38e5ba1d47e843e208ceef6cf9 (diff) |
posix-timers: fix deletion race
timer_delete does:
lock_timer();
timer->it_process = NULL;
unlock_timer();
release_posix_timer();
timer->it_process is checked in lock_timer() to prevent access to a
timer, which is on the way to be deleted, but the check happens after
idr_lock is dropped. This allows release_posix_timer() to delete the
timer before the lock code can check the timer:
CPU 0 CPU 1
lock_timer();
timer->it_process = NULL;
unlock_timer();
lock_timer()
spin_lock(idr_lock);
timer = idr_find();
spin_lock(timer->lock);
spin_unlock(idr_lock);
release_posix_timer();
spin_lock(idr_lock);
idr_remove(timer);
spin_unlock(idr_lock);
free_timer(timer);
if (timer->......)
Change the locking to prevent this.
Signed-off-by: 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 'include/linux/in6.h')
0 files changed, 0 insertions, 0 deletions