Commit 899f0429 authored Oct 09, 2017 by Andreas Gruenbacher Committed by Al Viro Oct 10, 2017

direct-io: Prevent NULL pointer access in submit_page_section



In the code added to function submit_page_section by commit b1058b98,
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>

parent 8a5776a5

fs/direct-io.c

+2 −1

Original line number	Original line	Diff line number	Diff line
	@@ -866,6 +866,7 @@ submit_page_section(struct dio dio, struct dio_submit sdio, struct page *page,
	*/		*/
	if (sdio->boundary) {		if (sdio->boundary) {
	ret = dio_send_cur_page(dio, sdio, map_bh);		ret = dio_send_cur_page(dio, sdio, map_bh);
			if (sdio->bio)
	dio_bio_submit(dio, sdio);		dio_bio_submit(dio, sdio);
	put_page(sdio->cur_page);		put_page(sdio->cur_page);
	sdio->cur_page = NULL;		sdio->cur_page = NULL;