fuse: Add memory barrier in fuse_uring_destruct

Add an smp_rmb() before checking list states in fuse_uring_destruct() to
ensure proper ordering between list modifications and emptiness checks.

During connection teardown lists are checked without holding a lock,
and ithout this barrier, the CPU executing fuse_uring_destruct()
might see inconsistent list states, leading to false WARN_ON triggers
even though the lists have been properly emptied.

The smp_rmb() ensures we see the final consistent state of all lists
after teardown operations complete on other CPUs.

This fixes occasional false WARN_ON triggers during connection
teardown.

Signed-off-by: Bernd Schubert <bschubert@ddn.com>

Author: bsbernd

fs/fuse/dev_uring.c

@@ -188,6 +188,9 @@ void fuse_uring_destruct(struct fuse_conn *fc)
 		if (!queue)
 			continue;
 
+		/* memory barrier to ensure we see the latest list state */
+		smp_rmb();
+
 		WARN_ON(!list_empty(&queue->ent_avail_queue));
 		WARN_ON(!list_empty(&queue->ent_w_req_queue));
 		WARN_ON(!list_empty(&queue->ent_commit_queue));