direct-io: Prevent NULL pointer access in submit_page_section

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 <agruenba@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Andreas Gruenbacher 2017-10-09 11:13:18 +02:00 committed by Al Viro
parent 8a5776a5f4
commit 899f0429c7

View File

@ -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;
}