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From: "Daniel Glöckner" <dg@emlix.com>
To: Mike Snitzer <snitzer@redhat.com>, Mikulas Patocka <mpatocka@redhat.com>
Cc: dm-devel@redhat.com, linux-block@vger.kernel.org,
	"Daniel Glöckner" <dg@emlix.com>
Subject: [PATCH] dm integrity: reinitialize __bi_remaining when reusing bio
Date: Tue, 25 Feb 2020 18:07:44 +0100	[thread overview]
Message-ID: <20200225170744.10485-1-dg@emlix.com> (raw)

In cases where dec_in_flight has to requeue the integrity_bio_wait work
to transfer the rest of the data, the __bi_remaining field of the bio
might already have been decremented to zero. Reusing the bio without
reinitializing that counter to 1 can then result in integrity_end_io
being called too early when the BIO_CHAIN flag is set, f.ex. due to
blk_queue_split. In our case this triggered the BUG() in
blk_mq_end_request when the hardware signalled completion of the bio
after integrity_end_io had modified it.

Signed-off-by: Daniel Glöckner <dg@emlix.com>
---
 drivers/md/dm-integrity.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index b225b3e445fa..8cea2978fc24 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -1438,6 +1438,7 @@ static void dec_in_flight(struct dm_integrity_io *dio)
 		if (likely(!bio->bi_status) && unlikely(bio_sectors(bio) != dio->range.n_sectors)) {
 			dio->range.logical_sector += dio->range.n_sectors;
 			bio_advance(bio, dio->range.n_sectors << SECTOR_SHIFT);
+			atomic_set(&bio->__bi_remaining, 1);
 			INIT_WORK(&dio->work, integrity_bio_wait);
 			queue_work(ic->wait_wq, &dio->work);
 			return;
-- 
2.17.1


WARNING: multiple messages have this Message-ID (diff)
From: "Daniel Glöckner" <dg@emlix.com>
To: Mike Snitzer <snitzer@redhat.com>, Mikulas Patocka <mpatocka@redhat.com>
Cc: linux-block@vger.kernel.org, dm-devel@redhat.com,
	"Daniel Glöckner" <dg@emlix.com>
Subject: [PATCH] dm integrity: reinitialize __bi_remaining when reusing bio
Date: Tue, 25 Feb 2020 18:07:44 +0100	[thread overview]
Message-ID: <20200225170744.10485-1-dg@emlix.com> (raw)

In cases where dec_in_flight has to requeue the integrity_bio_wait work
to transfer the rest of the data, the __bi_remaining field of the bio
might already have been decremented to zero. Reusing the bio without
reinitializing that counter to 1 can then result in integrity_end_io
being called too early when the BIO_CHAIN flag is set, f.ex. due to
blk_queue_split. In our case this triggered the BUG() in
blk_mq_end_request when the hardware signalled completion of the bio
after integrity_end_io had modified it.

Signed-off-by: Daniel Glöckner <dg@emlix.com>
---
 drivers/md/dm-integrity.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index b225b3e445fa..8cea2978fc24 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -1438,6 +1438,7 @@ static void dec_in_flight(struct dm_integrity_io *dio)
 		if (likely(!bio->bi_status) && unlikely(bio_sectors(bio) != dio->range.n_sectors)) {
 			dio->range.logical_sector += dio->range.n_sectors;
 			bio_advance(bio, dio->range.n_sectors << SECTOR_SHIFT);
+			atomic_set(&bio->__bi_remaining, 1);
 			INIT_WORK(&dio->work, integrity_bio_wait);
 			queue_work(ic->wait_wq, &dio->work);
 			return;
-- 
2.17.1


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             reply	other threads:[~2020-02-25 17:14 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-25 17:07 Daniel Glöckner [this message]
2020-02-25 17:07 ` [PATCH] dm integrity: reinitialize __bi_remaining when reusing bio Daniel Glöckner
2020-02-25 19:12 ` [dm-devel] " Christoph Hellwig
2020-02-25 19:54   ` Daniel Glöckner
2020-02-25 22:02     ` Christoph Hellwig
2020-02-26  1:22       ` Mike Snitzer

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