[PATCH v5 1/3] Staging: zram: Fix access of NULL pointer

From: Rashika Kheria
Date: Mon Oct 28 2013 - 07:48:09 EST

This patch fixes the bug in reset_store caused by accessing NULL pointer.
Hence, It introduces a check for bdev. It also removes unnecessary check
of bdev for fsync_bdev().

Signed-off-by: Rashika Kheria <rashika.kheria@xxxxxxxxx>

This revision fixes the following issues of the previous revision-
Seperate patch into Bug Fix and Smatch Fix

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 2c4ed52..d640a8f 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 -EBUSY;
/* 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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