tick: Cleanup NOHZ per cpu data on cpu down

Prarit reported a crash on CPU offline/online. The reason is that on
CPU down the NOHZ related per cpu data of the dead cpu is not cleaned
up. If at cpu online an interrupt happens before the per cpu tick
device is registered the irq_enter() check potentially sees stale data
and dereferences a NULL pointer.

Cleanup the data after the cpu is dead.

Reported-by: Prarit Bhargava <prarit@redhat.com>
Cc: stable@vger.kernel.org
Cc: Mike Galbraith <bitbucket@online.de>
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1305031451561.2886@ionos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2013-05-03 15:02:50 +02:00
parent fbd44a607a
commit 4b0c0f294f

View File

@ -904,7 +904,7 @@ void tick_cancel_sched_timer(int cpu)
hrtimer_cancel(&ts->sched_timer);
# endif
ts->nohz_mode = NOHZ_MODE_INACTIVE;
memset(ts, 0, sizeof(*ts));
}
#endif