Commit 46a51c80 authored by Rashika Kheria's avatar Rashika Kheria Committed by Greg Kroah-Hartman

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@vger.kernel.org>
Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
Signed-off-by: default avatarRashika Kheria <rashika.kheria@gmail.com>
Acked-by: default avatarMinchan Kim <minchan@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 59d3fe54
......@@ -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;
......
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