This is a note to let you know that I've just added the patch titled
Staging: zram: Fix access of NULL pointer
to my staging git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-next branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will also be merged in the next major kernel release
during the merge window.
If you have any questions about this process, please let me know.
>From 46a51c80216cb891f271ad021f59009f34677499 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
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().
Cc: stable <stable@xxxxxxxxxxxxxxx>
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>
---
drivers/staging/zram/zram_drv.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index b704d069..79ce363b 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -648,6 +648,9 @@ static ssize_t reset_store(struct device *dev,
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;
@@ -660,8 +663,7 @@ static ssize_t reset_store(struct device *dev,
return -EINVAL;
/* Make sure all pending I/O is finished */
- if (bdev)
- fsync_bdev(bdev);
+ fsync_bdev(bdev);
zram_reset_device(zram, true);
return len;
--
1.8.4.3.gca3854a
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