Re: [syzbot] [rdma?] possible deadlock in rds_trans_get_preferred

[Hillf Danton <hdanton@sina.com>]

> Date: Sun, 18 Oct 2026 12:14:36 -0700	[thread overview]
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    70dd4ee72eb2 Merge tag 'pinctrl-v7.3-3' of git://git.kerne..
> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> console output: https://syzkaller.appspot.com/x/log.txt?x=1271a69c580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=44ac479246d4559b
> dashboard link: https://syzkaller.appspot.com/bug?extid=ccdb5058c3df2d94811c
> compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
> userspace arch: i386
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15b9618e580000

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 70dd4ee72eb2

--- x/include/rdma/rdma_cm.h
+++ y/include/rdma/rdma_cm.h
@@ -167,6 +167,7 @@ struct rdma_cm_id *rdma_create_user_id(r
   * asynchronous operations associated with the id.
   */
 void rdma_destroy_id(struct rdma_cm_id *id);
+void rdma_destroy_id_wq(struct rdma_cm_id *id);
 
 /**
  * rdma_restrict_node_type - Restrict an RDMA identifier to specific
--- x/net/rds/ib.c
+++ y/net/rds/ib.c
@@ -486,7 +486,7 @@ static int rds_ib_laddr_check_cm(struct
 		 cm_id->device ? cm_id->device->node_type : -1);
 
 out:
-	rdma_destroy_id(cm_id);
+	rdma_destroy_id_wq(cm_id);
 
 	return ret;
 }
--- x/drivers/infiniband/core/cma_priv.h
+++ y/drivers/infiniband/core/cma_priv.h
@@ -110,6 +110,7 @@ struct rdma_id_private {
 	 */
 	struct rdma_restrack_entry     res;
 	struct rdma_ucm_ece ece;
+	struct work_struct destroy_work;
 };
 
 #if IS_ENABLED(CONFIG_INFINIBAND_ADDR_TRANS_CONFIGFS)
--- x/drivers/infiniband/core/cma.c
+++ y/drivers/infiniband/core/cma.c
@@ -2126,6 +2126,25 @@ void rdma_destroy_id(struct rdma_cm_id *
 }
 EXPORT_SYMBOL(rdma_destroy_id);
 
+static void destroy_id_work(struct work_struct *work)
+{
+	struct rdma_id_private *id_priv =
+		container_of(work, struct rdma_id_private, destroy_work);
+
+	mutex_lock(&id_priv->handler_mutex);
+	destroy_id_handler_unlock(id_priv);
+}
+
+void rdma_destroy_id_wq(struct rdma_cm_id *id)
+{
+	struct rdma_id_private *id_priv =
+		container_of(id, struct rdma_id_private, id);
+
+	INIT_WORK(&id_priv->destroy_work, destroy_id_work);
+	queue_work(cma_wq, &id_priv->destroy_work);
+}
+EXPORT_SYMBOL(rdma_destroy_id_wq);
+
 static int cma_rep_recv(struct rdma_id_private *id_priv)
 {
 	int ret;
--