Commit d3aa3e06 authored by 蒋家盛's avatar 蒋家盛 Committed by Mike Snitzer
Browse files

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: 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>
parent d9a02e01

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;
@@ -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)

drivers/md/dm-stats.h

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

drivers/md/dm.c

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