diff options
| author | Weijie Yang <weijie.yang@samsung.com> | 2014-11-13 15:19:05 -0800 |
|---|---|---|
| committer | Alex Shi <alex.shi@linaro.org> | 2015-05-11 21:31:02 +0800 |
| commit | 7aecdc886e2e9bacfaf2377067072fa63d649b21 (patch) | |
| tree | 85d8eb775fe3a65b6feb88dd995ac9c527d17c60 /drivers | |
| parent | ea56241654a2c7ef9a1122a7ad5c751527ed9b17 (diff) | |
zram: avoid kunmap_atomic() of a NULL pointer
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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit c406515239376fc93a30d5d03192182160cbd3fb)
Signed-off-by: Alex Shi <alex.shi@linaro.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 bf9fea268db4..8a1266ce8bbe 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -559,7 +559,8 @@ 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. */ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value); zram_free_page(zram, index); |