direct-io: Prevent NULL pointer access in submit_page_section

In the code added to function submit_page_section by commit b1058b9, 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: [email protected] # v3.10+ Signed-off-by: Andreas Gruenbacher <[email protected]> Reviewed-by: Jan Kara <[email protected]> Signed-off-by: Al Viro <[email protected]>
chewitt · Oct 11, 2017 · 899f042 · 899f042
1 parent 8a5776a
commit 899f042
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/fs/direct-io.c b/fs/direct-io.c
@@ -866,7 +866,8 @@ submit_page_section(struct dio *dio, struct dio_submit *sdio, struct page *page,
 	 */
 	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);
 		put_page(sdio->cur_page);
 		sdio->cur_page = NULL;
 	}