On Thu, 2 Jul 2020 at 20:45, Christoph Hellwig <hch@xxxxxx> wrote: > > On Thu, Jul 02, 2020 at 10:10:10AM -0400, Qian Cai wrote: > > On Mon, Jun 29, 2020 at 09:39:45PM +0200, Christoph Hellwig wrote: > > > Split out a __submit_bio_noacct helper for the actual de-recursion > > > algorithm, and simplify the loop by using a continue when we can't > > > enter the queue for a bio. > > > > > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> > > > > Reverting this commit and its dependencies, > > > > 5a6c35f9af41 block: remove direct_make_request > > ff93ea0ce763 block: shortcut __submit_bio_noacct for blk-mq drivers > > > > fixed the stack-out-of-bounds during boot, > > > > https://lore.kernel.org/linux-block/000000000000bcdeaa05a97280e4@xxxxxxxxxx/ > > Yikes. bio_alloc_bioset pokes into bio_list[1] in a totally > undocumented way. But even with that the problem should only show > up with "block: shortcut __submit_bio_noacct for blk-mq drivers". > > Can you try this patch? Applied your patch on top of linux-next 20200702 and tested on arm64 and x86_64 devices and the reported BUG fixed. Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> Tested-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> > > diff --git a/block/blk-core.c b/block/blk-core.c > index bf882b8d84450c..9f1bf8658b611a 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -1155,11 +1155,10 @@ static blk_qc_t __submit_bio_noacct(struct bio *bio) > static blk_qc_t __submit_bio_noacct_mq(struct bio *bio) > { > struct gendisk *disk = bio->bi_disk; > - struct bio_list bio_list; > + struct bio_list bio_list[2] = { }; > blk_qc_t ret = BLK_QC_T_NONE; > > - bio_list_init(&bio_list); > - current->bio_list = &bio_list; > + current->bio_list = bio_list; > > do { > WARN_ON_ONCE(bio->bi_disk != disk); > @@ -1174,7 +1173,7 @@ static blk_qc_t __submit_bio_noacct_mq(struct bio *bio) > } > > ret = blk_mq_submit_bio(bio); > - } while ((bio = bio_list_pop(&bio_list))); > + } while ((bio = bio_list_pop(&bio_list[0]))); > > current->bio_list = NULL; > return ret; ref: https://lkft.validation.linaro.org/scheduler/job/1538359#L288 https://lkft.validation.linaro.org/scheduler/job/1538360#L572 - Naresh
