This is a note to let you know that I've just added the patch titled
Staging: zram: Fix access of NULL pointer
to the 3.4-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:
staging-zram-fix-access-of-null-pointer.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From dccfb68c26308eb5fa3321110c9a4b51e89d67e3 Mon Sep 17 00:00:00 2001
From: Rashika Kheria <rashika.kheria@xxxxxxxxx>
Date: Wed, 30 Oct 2013 18:36:32 +0530
Subject: Staging: zram: Fix access of NULL pointer
From: Rashika Kheria <rashika.kheria@xxxxxxxxx>
commit 46a51c80216cb891f271ad021f59009f34677499 upstream.
This patch fixes the bug in reset_store caused by accessing NULL pointer.
The bdev gets its value from bdget_disk() which could fail when memory
pressure is severe and hence can return NULL because allocation of
inode in bdget could fail.
Hence, this patch introduces a check for bdev to prevent reference to a
NULL pointer in the later part of the code. It also removes unnecessary
check of bdev for fsync_bdev().
Acked-by: Jerome Marchand <jmarchan@xxxxxxxxxx>
Signed-off-by: Rashika Kheria <rashika.kheria@xxxxxxxxx>
Acked-by: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: Jianguo Wu <wujianguo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/zram/zram_sysfs.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/staging/zram/zram_sysfs.c
+++ b/drivers/staging/zram/zram_sysfs.c
@@ -95,6 +95,9 @@ static ssize_t reset_store(struct device
zram = dev_to_zram(dev);
bdev = bdget_disk(zram->disk, 0);
+ if (!bdev)
+ return -ENOMEM;
+
/* Do not reset an active device! */
if (bdev->bd_holders)
return -EBUSY;
@@ -107,8 +110,7 @@ static ssize_t reset_store(struct device
return -EINVAL;
/* Make sure all pending I/O is finished */
- if (bdev)
- fsync_bdev(bdev);
+ fsync_bdev(bdev);
down_write(&zram->init_lock);
if (zram->init_done)
Patches currently in stable-queue which might be from rashika.kheria@xxxxxxxxx are
queue-3.4/staging-zram-fix-access-of-null-pointer.patch
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