On 3/29/22 11:17 AM, daihuaigang129@xxxxxxx wrote:
From: daihuaigang <daihuaigang129@xxxxxxx>
bcache register add kobject_mutex then bch_register_mutex,
cache_set_free add bch_register_mutex then kobject_mutex.
fix AB-BA deadlock between cache register and cache_set_free.
Can you explain a bit more about,
- For "bcache register add kobject_mutex", which function referred by
"bcache register add", and where is the kobject_mutex.
- Where is bch_regsiter_mutex.
It is not clear for me to understand how hte AB-BA deadlock generated yet.
Thanks.
Coly Li
Signed-off-by: daihuaigang <daihuaigang129@xxxxxxx>
---
drivers/md/bcache/super.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index bf3de14..f17953c 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1690,10 +1690,8 @@ static void cache_set_free(struct closure *cl)
if (ca) {
ca->set = NULL;
c->cache = NULL;
- kobject_put(&ca->kobj);
}
-
if (c->moving_gc_wq)
destroy_workqueue(c->moving_gc_wq);
bioset_exit(&c->bio_split);
@@ -1704,6 +1702,8 @@ static void cache_set_free(struct closure *cl)
list_del(&c->list);
mutex_unlock(&bch_register_lock);
+ if (ca)
+ kobject_put(&ca->kobj);
pr_info("Cache set %pU unregistered\n", c->set_uuid);
wake_up(&unregister_wait);
