From 5df96f2b9f58a5d2dc1f30fe7de75e197f2c25f2 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 23 Jul 2020 10:42:09 -0400 Subject: [PATCH] dm integrity: fix integrity recalculation that is improperly skipped 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 --- drivers/md/dm-integrity.c | 4 ++-- drivers/md/dm.c | 17 +++++++++++++++++ include/linux/device-mapper.h | 1 + 3 files changed, 20 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c index 81dc5ff08909..a83a1de1e03f 100644 --- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -2420,7 +2420,7 @@ 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); @@ -2481,7 +2481,7 @@ 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 52449afd58eb..5b9de2f71bb0 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -143,6 +143,7 @@ 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; @@ -2408,6 +2409,7 @@ 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 */ @@ -2766,7 +2768,9 @@ 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); @@ -2863,7 +2867,9 @@ 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) @@ -3024,6 +3030,11 @@ 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); @@ -3040,6 +3051,12 @@ 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)); diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index 8750f2dc5613..73dec4b5d5be 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -426,6 +426,7 @@ const char *dm_device_name(struct mapped_device *md); int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid); struct gendisk *dm_disk(struct mapped_device *md); int dm_suspended(struct dm_target *ti); +int dm_post_suspending(struct dm_target *ti); int dm_noflush_suspending(struct dm_target *ti); void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors); union map_info *dm_get_rq_mapinfo(struct request *rq); -- 2.11.0