Hi Mike Please submit this to Linus and to RHEL-8.
Mikulas From: Mikulas Patocka <[email protected]> The patch adc0daad366b62ca1bce3e2958a40b0b71a8b8b3 broke recalculation on dm-integrity. The patch replaces a private variable "suspending" with a call to "dm_suspended". The problem is that dm_suspended returns true not only during suspend, but also during resume. This race condition could occur: 1. dm_integrity_resume calls queue_work(ic->recalc_wq, &ic->recalc_work) 2. integrity_recalc (&ic->recalc_work) preempts the current thread 3. integrity_recalc calls if (unlikely(dm_suspended(ic->ti))) goto unlock_ret; 4. integrity_recalc exits and no recalculating is done. In order to fix this race condition, we stop using dm_suspended and start using the variable "suspending" (that is only set during suspend, not during resume). Signed-off-by: Mikulas Patocka <[email protected]> Fixes: adc0daad366b ("dm: report suspended device during destroy") Cc: [email protected] # v4.18+ --- drivers/md/dm-integrity.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) Index: linux-2.6/drivers/md/dm-integrity.c =================================================================== --- linux-2.6.orig/drivers/md/dm-integrity.c 2020-06-29 14:49:59.000000000 +0200 +++ linux-2.6/drivers/md/dm-integrity.c 2020-07-22 15:48:49.000000000 +0200 @@ -204,13 +204,12 @@ struct dm_integrity_c { __u8 log2_blocks_per_bitmap_bit; unsigned char mode; + int suspending; int failed; struct crypto_shash *internal_hash; - struct dm_target *ti; - /* these variables are locked with endio_wait.lock */ struct rb_root in_progress; struct list_head wait_list; @@ -2420,7 +2419,7 @@ static void integrity_writer(struct work unsigned prev_free_sectors; /* the following test is not needed, but it tests the replay code */ - if (unlikely(dm_suspended(ic->ti)) && !ic->meta_dev) + if (READ_ONCE(ic->suspending) && !ic->meta_dev) return; spin_lock_irq(&ic->endio_wait.lock); @@ -2481,7 +2480,7 @@ static void integrity_recalc(struct work next_chunk: - if (unlikely(dm_suspended(ic->ti))) + if (unlikely(READ_ONCE(ic->suspending))) goto unlock_ret; range.logical_sector = le64_to_cpu(ic->sb->recalc_sector); @@ -2909,6 +2908,8 @@ static void dm_integrity_postsuspend(str del_timer_sync(&ic->autocommit_timer); + WRITE_ONCE(ic->suspending, 1); + if (ic->recalc_wq) drain_workqueue(ic->recalc_wq); @@ -2937,6 +2938,8 @@ static void dm_integrity_postsuspend(str #endif } + WRITE_ONCE(ic->suspending, 0); + BUG_ON(!RB_EMPTY_ROOT(&ic->in_progress)); ic->journal_uptodate = true; @@ -3767,7 +3770,6 @@ static int dm_integrity_ctr(struct dm_ta } ti->private = ic; ti->per_io_data_size = sizeof(struct dm_integrity_io); - ic->ti = ti; ic->in_progress = RB_ROOT; INIT_LIST_HEAD(&ic->wait_list); -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
