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| author | Rashika Kheria <rashika.kheria@gmail.com> | 2013-10-30 18:36:32 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-11-29 10:42:16 -0800 |
| commit | a552be366113e2c0334034f1ee654f67eb017dc0 (patch) | |
| tree | 739f2508b7b5aaf12d7e980a0979194d2f2c88c5 | |
| parent | f30d41a69154f0397173666a10d1a9fb072317fd (diff) | |
| download | lwn-a552be366113e2c0334034f1ee654f67eb017dc0.tar.gz lwn-a552be366113e2c0334034f1ee654f67eb017dc0.zip | |
Staging: zram: Fix access of NULL pointer
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 <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>
| -rw-r--r-- | drivers/staging/zram/zram_drv.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index 8f54c503ea04..ee6b4356f222 100644 --- 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 *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; @@ -659,8 +662,7 @@ 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; |