This is a note to let you know that I've just added the patch titled
dm stats: check for and propagate alloc_percpu failure
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-stats-check-for-and-propagate-alloc_percpu-failure.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d3aa3e060c4a80827eb801fc448debc9daa7c46b Mon Sep 17 00:00:00 2001
From: Jiasheng Jiang <jiasheng@xxxxxxxxxxx>
Date: Thu, 16 Mar 2023 14:55:06 +0800
Subject: dm stats: check for and propagate alloc_percpu failure
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;
@@ -196,11 +196,16 @@ void dm_stats_init(struct dm_stats *stat
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)
--- 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;
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1799,7 +1799,9 @@ static struct mapped_device *alloc_dev(i
bio_set_dev(&md->flush_bio, md->bdev);
md->flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC;
- 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);
Patches currently in stable-queue which might be from jiasheng@xxxxxxxxxxx are
queue-4.14/dm-stats-check-for-and-propagate-alloc_percpu-failure.patch
