From cab7ef0066401efb5ab2dea1d85f490ce9c626f3 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 23 Jul 2020 10:42:09 -0400 Subject: dm integrity: fix integrity recalculation that is improperly skipped commit 5df96f2b9f58a5d2dc1f30fe7de75e197f2c25f2 upstream. Commit adc0daad366b62ca1bce3e2958a40b0b71a8b8b3 ("dm: report suspended device during destroy") broke integrity recalculation. The problem is dm_suspended() returns true not only during suspend, but also during resume. So 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. To fix this race condition, add a function dm_post_suspending that is only true during the postsuspend phase and use it instead of dm_suspended(). Signed-off-by: Mikulas Patocka Fixes: adc0daad366b ("dm: report suspended device during destroy") Cc: stable vger kernel org # v4.18+ Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-integrity.c | 4 ++-- drivers/md/dm.c | 17 +++++++++++++++++ 2 files changed, 19 insertions(+), 2 deletions(-) (limited to 'drivers/md') diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c index d75a4ce7d12a..e8eeee680750 100644 --- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -2068,7 +2068,7 @@ static void integrity_writer(struct work_struct *w) 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 (unlikely(dm_post_suspending(ic->ti)) && !ic->meta_dev) return; spin_lock_irq(&ic->endio_wait.lock); @@ -2127,7 +2127,7 @@ static void integrity_recalc(struct work_struct *w) next_chunk: - if (unlikely(dm_suspended(ic->ti))) + if (unlikely(dm_post_suspending(ic->ti))) goto unlock_ret; range.logical_sector = le64_to_cpu(ic->sb->recalc_sector); diff --git a/drivers/md/dm.c b/drivers/md/dm.c index afc9f8406dce..874bd542a744 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -141,6 +141,7 @@ EXPORT_SYMBOL_GPL(dm_bio_get_target_bio_nr); #define DMF_NOFLUSH_SUSPENDING 5 #define DMF_DEFERRED_REMOVE 6 #define DMF_SUSPENDED_INTERNALLY 7 +#define DMF_POST_SUSPENDING 8 #define DM_NUMA_NODE NUMA_NO_NODE static int dm_numa_node = DM_NUMA_NODE; @@ -2355,6 +2356,7 @@ static void __dm_destroy(struct mapped_device *md, bool wait) if (!dm_suspended_md(md)) { dm_table_presuspend_targets(map); set_bit(DMF_SUSPENDED, &md->flags); + set_bit(DMF_POST_SUSPENDING, &md->flags); dm_table_postsuspend_targets(map); } /* dm_put_live_table must be before msleep, otherwise deadlock is possible */ @@ -2680,7 +2682,9 @@ retry: if (r) goto out_unlock; + set_bit(DMF_POST_SUSPENDING, &md->flags); dm_table_postsuspend_targets(map); + clear_bit(DMF_POST_SUSPENDING, &md->flags); out_unlock: mutex_unlock(&md->suspend_lock); @@ -2777,7 +2781,9 @@ static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_fla (void) __dm_suspend(md, map, suspend_flags, TASK_UNINTERRUPTIBLE, DMF_SUSPENDED_INTERNALLY); + set_bit(DMF_POST_SUSPENDING, &md->flags); dm_table_postsuspend_targets(map); + clear_bit(DMF_POST_SUSPENDING, &md->flags); } static void __dm_internal_resume(struct mapped_device *md) @@ -2938,6 +2944,11 @@ int dm_suspended_md(struct mapped_device *md) return test_bit(DMF_SUSPENDED, &md->flags); } +static int dm_post_suspending_md(struct mapped_device *md) +{ + return test_bit(DMF_POST_SUSPENDING, &md->flags); +} + int dm_suspended_internally_md(struct mapped_device *md) { return test_bit(DMF_SUSPENDED_INTERNALLY, &md->flags); @@ -2954,6 +2965,12 @@ int dm_suspended(struct dm_target *ti) } EXPORT_SYMBOL_GPL(dm_suspended); +int dm_post_suspending(struct dm_target *ti) +{ + return dm_post_suspending_md(dm_table_get_md(ti->table)); +} +EXPORT_SYMBOL_GPL(dm_post_suspending); + int dm_noflush_suspending(struct dm_target *ti) { return __noflush_suspending(dm_table_get_md(ti->table)); -- cgit v1.2.3