The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
Thanks,
Sasha
------------------ original commit in Linus's tree ------------------
>From 6e7132ed3c07bd8a6ce3db4bb307ef2852b322dc Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Date: Wed, 20 Mar 2024 18:43:11 +0100
Subject: [PATCH] dm snapshot: fix lockup in dm_exception_table_exit
There was reported lockup when we exit a snapshot with many exceptions.
Fix this by adding "cond_resched" to the loop that frees the exceptions.
Reported-by: John Pittman <jpittman@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
drivers/md/dm-snap.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index bf7a574499a34..0ace06d1bee38 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -684,8 +684,10 @@ static void dm_exception_table_exit(struct dm_exception_table *et,
for (i = 0; i < size; i++) {
slot = et->table + i;
- hlist_bl_for_each_entry_safe(ex, pos, n, slot, hash_list)
+ hlist_bl_for_each_entry_safe(ex, pos, n, slot, hash_list) {
kmem_cache_free(mem, ex);
+ cond_resched();
+ }
}
kvfree(et->table);
--
2.43.0
