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Staging: zram: Fix access of NULL pointer

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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@vger.kernel.org>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Rashika Kheria 2013-10-30 18:36:32 +05:30 committed by Greg Kroah-Hartman
parent 59d3fe5404
commit 46a51c8021
1 changed files with 4 additions and 2 deletions
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6
drivers/staging/zram/zram_drv.c
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@ -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;