This is a note to let you know that I've just added the patch titled
mm/vmpressure.c: fix race in vmpressure_work_fn()
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-vmpressure.c-fix-race-in-vmpressure_work_fn.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 91b57191cfd152c02ded0745250167d0263084f8 Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Date: Tue, 2 Dec 2014 15:59:28 -0800
Subject: mm/vmpressure.c: fix race in vmpressure_work_fn()
From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
commit 91b57191cfd152c02ded0745250167d0263084f8 upstream.
In some android devices, there will be a "divide by zero" exception.
vmpr->scanned could be zero before spin_lock(&vmpr->sr_lock).
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=88051
[akpm@xxxxxxxxxxxxxxxxxxxx: neaten]
Reported-by: ji_ang <ji_ang@xxxxxxx>
Cc: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/vmpressure.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
--- a/mm/vmpressure.c
+++ b/mm/vmpressure.c
@@ -165,6 +165,7 @@ static void vmpressure_work_fn(struct wo
unsigned long scanned;
unsigned long reclaimed;
+ spin_lock(&vmpr->sr_lock);
/*
* Several contexts might be calling vmpressure(), so it is
* possible that the work was rescheduled again before the old
@@ -173,11 +174,12 @@ static void vmpressure_work_fn(struct wo
* here. No need for any locks here since we don't care if
* vmpr->reclaimed is in sync.
*/
- if (!vmpr->scanned)
+ scanned = vmpr->scanned;
+ if (!scanned) {
+ spin_unlock(&vmpr->sr_lock);
return;
+ }
- spin_lock(&vmpr->sr_lock);
- scanned = vmpr->scanned;
reclaimed = vmpr->reclaimed;
vmpr->scanned = 0;
vmpr->reclaimed = 0;
Patches currently in stable-queue which might be from akpm@xxxxxxxxxxxxxxxxxxxx are
queue-3.14/mm-vmpressure.c-fix-race-in-vmpressure_work_fn.patch
queue-3.14/mm-fix-swapoff-hang-after-page-migration-and-fork.patch
queue-3.14/mm-frontswap-invalidate-expired-data-on-a-dup-store-failure.patch
queue-3.14/mm-fix-anon_vma_clone-error-treatment.patch
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