From: Jiasheng Jiang <jiasheng@xxxxxxxxxxx>
commit d3aa3e060c4a80827eb801fc448debc9daa7c46b upstream.
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@xxxxxxxxxxxxxxx
Signed-off-by: Jiasheng Jiang <jiasheng@xxxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/dm-stats.c | 7 ++++++-
drivers/md/dm-stats.h | 2 +-
drivers/md/dm.c | 4 +++-
3 files changed, 10 insertions(+), 3 deletions(-)
--- a/drivers/md/dm-stats.c
+++ b/drivers/md/dm-stats.c
@@ -188,7 +188,7 @@ static int dm_stat_in_flight(struct dm_s
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 *stat
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)
--- 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;
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1818,7 +1818,9 @@ static struct mapped_device *alloc_dev(i
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);
