diff options
| author | Weijie Yang <weijie.yang@samsung.com> | 2014-11-13 15:19:05 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-21 09:23:00 -0800 |
| commit | 340eb9b208105e5c86b936d7f8b8d8e865f1bc6f (patch) | |
| tree | f7854fdd1255e15a5149763bb9f803e86d9e9006 /drivers | |
| parent | 882b3ba4a885d3bc458e09ad951b44047b3b27a7 (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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -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 51c557cfd92b..d8ddb8e2adc1 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -447,7 +447,8 @@ 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); |