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authorThomas Gleixner <tglx@linutronix.de>2013-05-03 15:02:50 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-05-19 10:54:40 -0700
commit33b7cfcb34b4ae37cde7a8a1c97c9be27677e931 (patch)
tree79d2091b2bcdfe3fda377633dc0322d0ce903781 /kernel
parented032fd4d81041e4002fc55ff1832ee588f103da (diff)
tick: Cleanup NOHZ per cpu data on cpu down
commit 4b0c0f294f60abcdd20994a8341a95c8ac5eeb96 upstream. 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: 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/time/tick-sched.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 01d8e62ac369..6570548d0886 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -866,7 +866,7 @@ 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