tree 20ba1584eefb7ed75f6f8536f40e55966294cf4f
parent 108150ea78003044e41150c75259447b2c0953b6
author Oleg Nesterov <oleg@tv-sign.ru> 1130150043 +0400
committer Linus Torvalds <torvalds@g5.osdl.org> 1130166755 -0700

[PATCH] posix-timers: remove false BUG_ON() from run_posix_cpu_timers()

do_exit() clears ->it_##clock##_expires, but nothing prevents
another cpu to attach the timer to exiting process after that.

After exit_notify() does 'write_unlock_irq(&tasklist_lock)' and
before do_exit() calls 'schedule() local timer interrupt can find
tsk->exit_state != 0. If that state was EXIT_DEAD (or another cpu
does sys_wait4) interrupted task has ->signal == NULL.

At this moment exiting task has no pending cpu timers, they were cleaned
up in __exit_signal()->posix_cpu_timers_exit{,_group}(), so we can just
return from irq.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>