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dm stats: check for and propagate alloc_percpu failure

Browse source 
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: fd2ed4d252 ("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>
This commit is contained in:
Jiasheng Jiang 2023-03-16 14:55:06 +08:00 • committed by Mike Snitzer
parent d9a02e016a
commit d3aa3e060c
3 changed files with 10 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
drivers/md/dm-stats.c
View file

@ -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)

2
drivers/md/dm-stats.h
View file

@ -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;

4
drivers/md/dm.c
View file

@ -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);