Messages in this thread Patch in this message | | | Date | Sat, 17 May 2008 19:14:19 +0400 | From | Oleg Nesterov <> | Subject | [PATCH 2/3] posix timers: timer_delete: remove the bogus "->it_process != NULL" check |
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sys_timer_delete() and itimer_delete() check "timer->it_process != NULL", this looks completely bogus. ->it_process == NULL means that this timer is already under destruction or it is not fully initialized, this must not happen.
sys_timer_delete: the timer is locked, and lock_timer() can't succeed if ->it_process == NULL.
itimer_delete: it is called by exit_itimers() when there are no other threads which can play with signal_struct->posix_timers.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com>
--- 25/kernel/posix-timers.c~2_TIMER_DEL_NO_CHECK 2008-05-17 16:03:24.000000000 +0400 +++ 25/kernel/posix-timers.c 2008-05-17 16:31:26.000000000 +0400 @@ -855,11 +855,10 @@ retry_delete: * This keeps any tasks waiting on the spin lock from thinking * they got something (see the lock code above). */ - if (timer->it_process) { - if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID)) - put_task_struct(timer->it_process); - timer->it_process = NULL; - } + if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID)) + put_task_struct(timer->it_process); + timer->it_process = NULL; + unlock_timer(timer, flags); release_posix_timer(timer, IT_ID_SET); return 0; @@ -884,11 +883,10 @@ retry_delete: * This keeps any tasks waiting on the spin lock from thinking * they got something (see the lock code above). */ - if (timer->it_process) { - if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID)) - put_task_struct(timer->it_process); - timer->it_process = NULL; - } + if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID)) + put_task_struct(timer->it_process); + timer->it_process = NULL; + unlock_timer(timer, flags); release_posix_timer(timer, IT_ID_SET); }
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