3.13.11-ckt12 -stable review patch. If anyone has any objections, please let me know.
------------------ From: Weijie Yang <[email protected]> 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 <[email protected]> Cc: Sergey Senozhatsky <[email protected]> Cc: Dan Streetman <[email protected]> Cc: Nitin Gupta <[email protected]> Cc: Weijie Yang <[email protected]> Acked-by: Jerome Marchand <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Kamal Mostafa <[email protected]> --- drivers/staging/zram/zram_drv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index e2f0add..63c2a5b 100644 --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -430,7 +430,8 @@ 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. */ zram_free_page(zram, index); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
