3.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Rashika Kheria <rashika.khe...@gmail.com>
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 <jmarc...@redhat.com>
Signed-off-by: Rashika Kheria <rashika.khe...@gmail.com>
Acked-by: Minchan Kim <minc...@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/staging/zram/zram_drv.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -647,6 +647,9 @@ 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;
@@ -659,8 +662,7 @@ 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);
zram_reset_device(zram, true);
return len;
--
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