From b35f8caa0890169000fec22902290d9a15274cbd Mon Sep 17 00:00:00 2001 From: Milan Broz Date: Mon, 16 Mar 2009 17:44:36 +0000 Subject: [PATCH] dm crypt: wait for endio to complete before destruction The following oops has been reported when dm-crypt runs over a loop device. ... [ 70.381058] Process loop0 (pid: 4268, ti=cf3b2000 task=cf1cc1f0 task.ti=cf3b2000) ... [ 70.381058] Call Trace: [ 70.381058] [] ? crypt_dec_pending+0x5e/0x62 [dm_crypt] [ 70.381058] [] ? crypt_endio+0xa2/0xaa [dm_crypt] [ 70.381058] [] ? crypt_endio+0x0/0xaa [dm_crypt] [ 70.381058] [] ? bio_endio+0x2b/0x2e [ 70.381058] [] ? dec_pending+0x224/0x23b [dm_mod] [ 70.381058] [] ? clone_endio+0x79/0xa4 [dm_mod] [ 70.381058] [] ? clone_endio+0x0/0xa4 [dm_mod] [ 70.381058] [] ? bio_endio+0x2b/0x2e [ 70.381058] [] ? loop_thread+0x380/0x3b7 [ 70.381058] [] ? do_lo_send_aops+0x0/0x165 [ 70.381058] [] ? autoremove_wake_function+0x0/0x33 [ 70.381058] [] ? loop_thread+0x0/0x3b7 When a table is being replaced, it waits for I/O to complete before destroying the mempool, but the endio function doesn't call mempool_free() until after completing the bio. Fix it by swapping the order of those two operations. The same problem occurs in dm.c with md referenced after dec_pending. Again, we swap the order. Cc: stable@kernel.org Signed-off-by: Milan Broz Signed-off-by: Alasdair G Kergon --- drivers/md/dm-crypt.c | 17 ++++++++++------- drivers/md/dm.c | 32 +++++++++++++++++++------------- 2 files changed, 29 insertions(+), 20 deletions(-) diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index ebab49f8cc1d..bfefd079a955 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -568,19 +568,22 @@ static void crypt_inc_pending(struct dm_crypt_io *io) static void crypt_dec_pending(struct dm_crypt_io *io) { struct crypt_config *cc = io->target->private; + struct bio *base_bio = io->base_bio; + struct dm_crypt_io *base_io = io->base_io; + int error = io->error; if (!atomic_dec_and_test(&io->pending)) return; - if (likely(!io->base_io)) - bio_endio(io->base_bio, io->error); + mempool_free(io, cc->io_pool); + + if (likely(!base_io)) + bio_endio(base_bio, error); else { - if (io->error && !io->base_io->error) - io->base_io->error = io->error; - crypt_dec_pending(io->base_io); + if (error && !base_io->error) + base_io->error = error; + crypt_dec_pending(base_io); } - - mempool_free(io, cc->io_pool); } /* diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 51ba1db4b3e7..8d40f27cce89 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -525,9 +525,12 @@ static int __noflush_suspending(struct mapped_device *md) static void dec_pending(struct dm_io *io, int error) { unsigned long flags; + int io_error; + struct bio *bio; + struct mapped_device *md = io->md; /* Push-back supersedes any I/O errors */ - if (error && !(io->error > 0 && __noflush_suspending(io->md))) + if (error && !(io->error > 0 && __noflush_suspending(md))) io->error = error; if (atomic_dec_and_test(&io->io_count)) { @@ -537,24 +540,27 @@ static void dec_pending(struct dm_io *io, int error) * This must be handled before the sleeper on * suspend queue merges the pushback list. */ - spin_lock_irqsave(&io->md->pushback_lock, flags); - if (__noflush_suspending(io->md)) - bio_list_add(&io->md->pushback, io->bio); + spin_lock_irqsave(&md->pushback_lock, flags); + if (__noflush_suspending(md)) + bio_list_add(&md->pushback, io->bio); else /* noflush suspend was interrupted. */ io->error = -EIO; - spin_unlock_irqrestore(&io->md->pushback_lock, flags); + spin_unlock_irqrestore(&md->pushback_lock, flags); } end_io_acct(io); - if (io->error != DM_ENDIO_REQUEUE) { - trace_block_bio_complete(io->md->queue, io->bio); + io_error = io->error; + bio = io->bio; - bio_endio(io->bio, io->error); - } + free_io(md, io); + + if (io_error != DM_ENDIO_REQUEUE) { + trace_block_bio_complete(md->queue, bio); - free_io(io->md, io); + bio_endio(bio, io_error); + } } } @@ -562,6 +568,7 @@ static void clone_endio(struct bio *bio, int error) { int r = 0; struct dm_target_io *tio = bio->bi_private; + struct dm_io *io = tio->io; struct mapped_device *md = tio->io->md; dm_endio_fn endio = tio->ti->type->end_io; @@ -585,15 +592,14 @@ static void clone_endio(struct bio *bio, int error) } } - dec_pending(tio->io, error); - /* * Store md for cleanup instead of tio which is about to get freed. */ bio->bi_private = md->bs; - bio_put(bio); free_tio(md, tio); + bio_put(bio); + dec_pending(io, error); } static sector_t max_io_len(struct mapped_device *md, -- 2.20.1