From d75e8540fd8bedc8ee8d11941a7aed3a86735c47 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Mon, 9 Oct 2017 11:13:18 +0200 Subject: [PATCH] direct-io: Prevent NULL pointer access in submit_page_section commit 899f0429c7d3eed886406cd72182bee3b96aa1f9 upstream. In the code added to function submit_page_section by commit b1058b981, sdio->bio can currently be NULL when calling dio_bio_submit. This then leads to a NULL pointer access in dio_bio_submit, so check for a NULL bio in submit_page_section before trying to submit it instead. Fixes xfstest generic/250 on gfs2. Cc: stable@vger.kernel.org # v3.10+ Signed-off-by: Andreas Gruenbacher Reviewed-by: Jan Kara Signed-off-by: Al Viro Signed-off-by: Willy Tarreau --- fs/direct-io.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/direct-io.c b/fs/direct-io.c index e17d919aa6d8..4007749a478e 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -759,7 +759,8 @@ out: */ if (sdio->boundary) { ret = dio_send_cur_page(dio, sdio, map_bh); - dio_bio_submit(dio, sdio); + if (sdio->bio) + dio_bio_submit(dio, sdio); page_cache_release(sdio->cur_page); sdio->cur_page = NULL; } -- 2.20.1