From d3aa3e060c4a80827eb801fc448debc9daa7c46b Mon Sep 17 00:00:00 2001 From: Jiasheng Jiang Date: Thu, 16 Mar 2023 14:55:06 +0800 Subject: [PATCH] dm stats: check for and propagate alloc_percpu failure Check alloc_precpu()'s return value and return an error from dm_stats_init() if it fails. Update alloc_dev() to fail if dm_stats_init() does. Otherwise, a NULL pointer dereference will occur in dm_stats_cleanup() even if dm-stats isn't being actively used. Fixes: fd2ed4d25270 ("dm: add statistics support") Cc: stable@vger.kernel.org Signed-off-by: Jiasheng Jiang Signed-off-by: Mike Snitzer --- drivers/md/dm-stats.c | 7 ++++++- drivers/md/dm-stats.h | 2 +- drivers/md/dm.c | 4 +++- 3 files changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/md/dm-stats.c b/drivers/md/dm-stats.c index c21a19ab73f7..db2d997a6c18 100644 --- a/drivers/md/dm-stats.c +++ b/drivers/md/dm-stats.c @@ -188,7 +188,7 @@ static int dm_stat_in_flight(struct dm_stat_shared *shared) atomic_read(&shared->in_flight[WRITE]); } -void dm_stats_init(struct dm_stats *stats) +int dm_stats_init(struct dm_stats *stats) { int cpu; struct dm_stats_last_position *last; @@ -197,11 +197,16 @@ void dm_stats_init(struct dm_stats *stats) INIT_LIST_HEAD(&stats->list); stats->precise_timestamps = false; stats->last = alloc_percpu(struct dm_stats_last_position); + if (!stats->last) + return -ENOMEM; + for_each_possible_cpu(cpu) { last = per_cpu_ptr(stats->last, cpu); last->last_sector = (sector_t)ULLONG_MAX; last->last_rw = UINT_MAX; } + + return 0; } void dm_stats_cleanup(struct dm_stats *stats) diff --git a/drivers/md/dm-stats.h b/drivers/md/dm-stats.h index 0bc152c8e4f3..c6728c8b4159 100644 --- a/drivers/md/dm-stats.h +++ b/drivers/md/dm-stats.h @@ -21,7 +21,7 @@ struct dm_stats_aux { unsigned long long duration_ns; }; -void dm_stats_init(struct dm_stats *st); +int dm_stats_init(struct dm_stats *st); void dm_stats_cleanup(struct dm_stats *st); struct mapped_device; diff --git a/drivers/md/dm.c b/drivers/md/dm.c index eace45a18d45..b6ace995b9ca 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2097,7 +2097,9 @@ static struct mapped_device *alloc_dev(int minor) if (!md->pending_io) goto bad; - dm_stats_init(&md->stats); + r = dm_stats_init(&md->stats); + if (r < 0) + goto bad; /* Populate the mapping, nobody knows we exist yet */ spin_lock(&_minor_lock); -- 2.39.5