3.17-stable review patch. If anyone has any objections, please let me know.
------------------ From: Weijie Yang <weijie.y...@samsung.com> 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.y...@samsung.com> Cc: Sergey Senozhatsky <sergey.senozhat...@gmail.com> Cc: Dan Streetman <ddstr...@ieee.org> Cc: Nitin Gupta <ngu...@vflare.org> Cc: Weijie Yang <weijie.yang...@gmail.com> Acked-by: Jerome Marchand <jmarc...@redhat.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- drivers/block/zram/zram_drv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -476,7 +476,8 @@ static int zram_bvec_write(struct zram * } 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); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/