Re: block: oopses on 4.13.*, 4.14.* and 4.15-rc2 (bisected)
From: Jens Axboe <axboe@kernel.dk>
Date: 2017-12-08 20:08:48
Also in:
lkml
Subsystem:
block layer, scsi subsystem, scsi target subsystem, the rest · Maintainers:
Jens Axboe, "James E.J. Bottomley", "Martin K. Petersen", Linus Torvalds
On 12/08/2017 08:38 AM, Michele Ballabio wrote:
Hi,
kernels 4.13.*, 4.14.* 4.15-rc2 crash on occasion, especially
on x86-32 systems. To trigger the problem, run as root:
while true
do
/sbin/udevadm trigger --type=subsystems --action=change
/sbin/udevadm trigger --type=devices --action=change
/sbin/udevadm settle --timeout=120
done
(Thanks to Patrick Volkerding for the reproducer).
Sometimes the kernel oopses immediately, sometimes a bit later (less than
five minutes).
The bisection pointed to commit caa4b02476e31fc7933d2138062f7f355d3cd8f7
(blk-map: call blk_queue_bounce from blk_rq_append_bio). A revert
fixes the problem (tested on 4.13 and master).Thanks for your report - can you try the below patch? Totally untested...
diff --git a/block/blk-map.c b/block/blk-map.c
index b21f8e86f120..ad970719a1fc 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c@@ -12,22 +12,22 @@ #include "blk.h" /* - * Append a bio to a passthrough request. Only works can be merged into - * the request based on the driver constraints. + * Append a bio to a passthrough request. Only works if the bio can be merged + * into the request based on the driver constraints. */ -int blk_rq_append_bio(struct request *rq, struct bio *bio) +int blk_rq_append_bio(struct request *rq, struct bio **bio) { - blk_queue_bounce(rq->q, &bio); + blk_queue_bounce(rq->q, bio); if (!rq->bio) { - blk_rq_bio_prep(rq->q, rq, bio); + blk_rq_bio_prep(rq->q, rq, *bio); } else { - if (!ll_back_merge_fn(rq->q, rq, bio)) + if (!ll_back_merge_fn(rq->q, rq, *bio)) return -EINVAL; - rq->biotail->bi_next = bio; - rq->biotail = bio; - rq->__data_len += bio->bi_iter.bi_size; + rq->biotail->bi_next = *bio; + rq->biotail = *bio; + rq->__data_len += (*bio)->bi_iter.bi_size; } return 0;
@@ -73,8 +73,9 @@ static int __blk_rq_map_user_iov(struct request *rq, * We link the bounce buffer in and could have to traverse it * later so we have to get a ref to prevent it from being freed */ - ret = blk_rq_append_bio(rq, bio); bio_get(bio); + + ret = blk_rq_append_bio(rq, &bio); if (ret) { bio_endio(bio); __blk_rq_unmap_user(orig_bio);
@@ -236,7 +237,7 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, if (do_copy) rq->rq_flags |= RQF_COPY_USER; - ret = blk_rq_append_bio(rq, bio); + ret = blk_rq_append_bio(rq, &bio); if (unlikely(ret)) { /* request is too big */ bio_put(bio);
diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
index a4f28b7e4c65..e18877177f1b 100644
--- a/drivers/scsi/osd/osd_initiator.c
+++ b/drivers/scsi/osd/osd_initiator.c@@ -1576,7 +1576,9 @@ static struct request *_make_request(struct request_queue *q, bool has_write, return req; for_each_bio(bio) { - ret = blk_rq_append_bio(req, bio); + struct bio *bounce_bio = bio; + + ret = blk_rq_append_bio(req, &bounce_bio); if (ret) return ERR_PTR(ret); }
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index 7c69b4a9694d..0d99b242e82e 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c@@ -920,7 +920,7 @@ pscsi_map_sg(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents, " %d i: %d bio: %p, allocating another" " bio\n", bio->bi_vcnt, i, bio); - rc = blk_rq_append_bio(req, bio); + rc = blk_rq_append_bio(req, &bio); if (rc) { pr_err("pSCSI: failed to append bio\n"); goto fail;
@@ -938,7 +938,7 @@ pscsi_map_sg(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents, } if (bio) { - rc = blk_rq_append_bio(req, bio); + rc = blk_rq_append_bio(req, &bio); if (rc) { pr_err("pSCSI: failed to append bio\n"); goto fail;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 8089ca17db9a..06b88d38f611 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h@@ -948,7 +948,7 @@ extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src, extern void blk_rq_unprep_clone(struct request *rq); extern blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *rq); -extern int blk_rq_append_bio(struct request *rq, struct bio *bio); +extern int blk_rq_append_bio(struct request *rq, struct bio **bio); extern void blk_delay_queue(struct request_queue *, unsigned long); extern void blk_queue_split(struct request_queue *, struct bio **); extern void blk_recount_segments(struct request_queue *, struct bio *);
--
Jens Axboe