Re: [syzbot] [nvme?] BUG: corrupted list in nvmet_fc_remove_port

[Hillf Danton <hdanton@sina.com>]

> Date: Sun, 11 Oct 2026 10:32:37 -0700	[thread overview]
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    a5ebb76233b7 Merge tag 'edac_urgent_for_v7.3_rc7' of git:/..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1494923e580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
> dashboard link: https://syzkaller.appspot.com/bug?extid=c98b21427617af7f547a
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=126a0f15580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=166a0f15580000

#syz test

--- x/drivers/nvme/target/fc.c
+++ y/drivers/nvme/target/fc.c
@@ -113,6 +113,7 @@ struct nvmet_fc_tgtport {
 	struct nvmet_fc_port_entry	*pe;
 	struct kref			ref;
 	u32				max_sg_cnt;
+	int				assoc_freed;
 };
 
 struct nvmet_fc_port_entry {
@@ -1271,9 +1272,17 @@ nvmet_fc_portentry_bind(struct nvmet_fc_
 static void
 nvmet_fc_portentry_unbind(struct nvmet_fc_port_entry *pe)
 {
+	struct nvmet_fc_port_entry *entry;
 	unsigned long flags;
 
 	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
+	list_for_each_entry(entry, &nvmet_fc_portentry_list, pe_list) {
+		if (entry == pe)
+			goto out;
+	}
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+	return;
+out:
 	if (pe->tgtport) {
 		nvmet_fc_tgtport_put(pe->tgtport);
 		pe->tgtport->pe = NULL;
@@ -1474,14 +1483,20 @@ static void
 __nvmet_fc_free_assocs(struct nvmet_fc_tgtport *tgtport)
 {
 	struct nvmet_fc_tgt_assoc *assoc;
+	unsigned long flags;
 
+	if (tgtport->assoc_freed)
+		return;
+	tgtport->assoc_freed = 1;
 	rcu_read_lock();
+	spin_lock_irqsave(&tgtport->lock, flags);
 	list_for_each_entry_rcu(assoc, &tgtport->assoc_list, a_list) {
 		if (!nvmet_fc_tgt_a_get(assoc))
 			continue;
 		nvmet_fc_schedule_delete_assoc(assoc);
 		nvmet_fc_tgt_a_put(assoc);
 	}
+	spin_unlock_irqrestore(&tgtport->lock, flags);
 	rcu_read_unlock();
 }
 
@@ -1643,8 +1658,10 @@ nvmet_fc_unregister_targetport(struct nv
 
 	nvmet_fc_portentry_unbind_tgt(tgtport);
 
+	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
 	/* terminate any outstanding associations */
 	__nvmet_fc_free_assocs(tgtport);
+	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
 
 	flush_workqueue(nvmet_wq);
 
@@ -2927,8 +2944,10 @@ nvmet_fc_remove_port(struct nvmet_port *
 	nvmet_fc_portentry_unbind(pe);
 
 	if (tgtport) {
+		spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
 		/* terminate any outstanding associations */
 		__nvmet_fc_free_assocs(tgtport);
+		spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
 		nvmet_fc_tgtport_put(tgtport);
 	}
 
--