Commit-ID: 0e334db6bb4b1fd1e2d72c1f3d8f004313cd9f94 Gitweb: https://git.kernel.org/tip/0e334db6bb4b1fd1e2d72c1f3d8f004313cd9f94 Author: Thomas Gleixner <[email protected]> AuthorDate: Mon, 17 Dec 2018 13:31:05 +0100 Committer: Ingo Molnar <[email protected]> CommitDate: Mon, 17 Dec 2018 17:35:45 +0100
posix-timers: Fix division by zero bug The signal delivery path of posix-timers can try to rearm the timer even if the interval is zero. That's handled for the common case (hrtimer) but not for alarm timers. In that case the forwarding function raises a division by zero exception. The handling for hrtimer based posix timers is wrong because it marks the timer as active despite the fact that it is stopped. Move the check from common_hrtimer_rearm() to posixtimer_rearm() to cure both issues. Reported-by: [email protected] Signed-off-by: Thomas Gleixner <[email protected]> Cc: John Stultz <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- kernel/time/posix-timers.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c index bd62b5eeb5a0..31f49ae80f43 100644 --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -289,9 +289,6 @@ static void common_hrtimer_rearm(struct k_itimer *timr) { struct hrtimer *timer = &timr->it.real.timer; - if (!timr->it_interval) - return; - timr->it_overrun += hrtimer_forward(timer, timer->base->get_time(), timr->it_interval); hrtimer_restart(timer); @@ -317,7 +314,7 @@ void posixtimer_rearm(struct kernel_siginfo *info) if (!timr) return; - if (timr->it_requeue_pending == info->si_sys_private) { + if (timr->it_interval && timr->it_requeue_pending == info->si_sys_private) { timr->kclock->timer_rearm(timr); timr->it_active = 1;
