From: Jiasheng Jiang jiasheng@iscas.ac.cn

mainline inclusion from mainline-v6.3-rc4 commit d3aa3e060c4a80827eb801fc448debc9daa7c46b category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I7I2L8

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h...

--------------------------------

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 jiasheng@iscas.ac.cn Signed-off-by: Mike Snitzer snitzer@kernel.org

Conflicts: drivers/md/dm-stats.c drivers/md/dm.c

Signed-off-by: Li Lingfeng lilingfeng3@huawei.com --- 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 55443a6598fa..4029281ca383 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; @@ -196,11 +196,16 @@ void dm_stats_init(struct dm_stats *stats) mutex_init(&stats->mutex); INIT_LIST_HEAD(&stats->list); 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 2ddfae678f32..dcac11fce03b 100644 --- a/drivers/md/dm-stats.h +++ b/drivers/md/dm-stats.h @@ -22,7 +22,7 @@ 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 1cb2a84f2403..0c9ce43f3b53 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1904,7 +1904,9 @@ static struct mapped_device *alloc_dev(int minor) if (!md->bdev) 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);