diff options
| author | Weijie Yang <weijie.yang@samsung.com> | 2014-11-13 15:19:05 -0800 |
|---|---|---|
| committer | Luis Henriques <luis.henriques@canonical.com> | 2014-11-27 11:21:50 +0000 |
| commit | cbfecaffe161af362d85c06257b3f92c8092cb0c (patch) | |
| tree | ea840d375bc29e1e010fb750e2f2510de7190bf8 /drivers/block/zram/zram_drv.c | |
| parent | a7001a90b670178c92d08c3ea1e857d7ef3c5470 (diff) | |
zram: avoid kunmap_atomic() of a NULL pointer
commit c406515239376fc93a30d5d03192182160cbd3fb upstream.
zram could kunmap_atomic() a NULL pointer in a rare situation: a zram
page becomes a full-zeroed page after a partial write io. The current
code doesn't handle this case and performs kunmap_atomic() on a NULL
pointer, which panics the kernel.
This patch fixes this issue.
Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Weijie Yang <weijie.yang.kh@gmail.com>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Diffstat (limited to 'drivers/block/zram/zram_drv.c')
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 36e54be402df..2b30485cbd26 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -459,7 +459,8 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, } if (page_zero_filled(uncmem)) { - kunmap_atomic(user_mem); + if (user_mem) + kunmap_atomic(user_mem); /* Free memory associated with this sector now. */ write_lock(&zram->meta->tb_lock); zram_free_page(zram, index); |