Commit 23b7b357 authored by 蒋家盛's avatar 蒋家盛 Committed by Li Lingfeng
Browse files

dm stats: check for and propagate alloc_percpu failure 

mainline inclusion
from mainline-v6.3-rc4
commit d3aa3e06
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=v6.4-rc6&id=d3aa3e060c4a80827eb801fc448debc9daa7c46b



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

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: fd2ed4d2 ("dm: add statistics support")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarJiasheng Jiang <jiasheng@iscas.ac.cn>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>

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

Signed-off-by: default avatarLi Lingfeng <lilingfeng3@huawei.com>
parent 82c66282

drivers/md/dm-stats.c

+6 −1
Original line number Diff line number Diff line
@@ -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)

drivers/md/dm-stats.h

+1 −1
Original line number Diff line number Diff line
@@ -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;

drivers/md/dm.c

+3 −1
Original line number Diff line number Diff line
@@ -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);