[no subject]

From: Sebastian Ott
Date: Fri Nov 28 2014 - 10:03:14 EST

Commit eb7e7d766326 ("s390: Replace __get_cpu_var uses") broke machine
check handling.

We copy machine check information from per-cpu to a stack variable for
local processing. Next we should zap the per-cpu variable, not the
stack variable.

Signed-off-by: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Acked-by: Christoph Lameter <cl@xxxxxxxxx>
Fixes: eb7e7d766326 ("s390: Replace __get_cpu_var uses")
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Sorry about the delay. Was on vacation.

Patch applied to percpu/for-3.18-fixes w/ minor updates to the patch
subject and description. Will push out to Linus soon.


arch/s390/kernel/nmi.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index dd1c24c..3f51cf4 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -54,12 +54,8 @@ void s390_handle_mcck(void)
- /*
- * Ummm... Does this make sense at all? Copying the percpu struct
- * and then zapping it one statement later?
- */
- memcpy(&mcck, this_cpu_ptr(&cpu_mcck), sizeof(mcck));
- memset(&mcck, 0, sizeof(struct mcck_struct));
+ mcck = *this_cpu_ptr(&cpu_mcck);
+ memset(this_cpu_ptr(&cpu_mcck), 0, sizeof(mcck));

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