Re: [syzbot] [net?] BUG: unable to handle kernel paging request in nsim_queue_free

[Hillf Danton <hdanton@sina.com>]

> Date: Tue, 12 Aug 2025 02:58:28 -0700	[thread overview]
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    53e760d89498 Merge tag 'nfsd-6.17-1' of git://git.kernel.o..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16c415a2580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=d67d3af29f50297e
> dashboard link: https://syzkaller.appspot.com/bug?extid=8aa80c6232008f7b957d
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=151be9a2580000

#syz test

--- x/drivers/net/netdevsim/netdev.c
+++ y/drivers/net/netdevsim/netdev.c
@@ -981,6 +981,7 @@ err_free_prev:
 	while (i--)
 		kfree(ns->rq[i]);
 	kfree(ns->rq);
+	ns->rq = NULL;
 	return -ENOMEM;
 }
 
@@ -989,6 +990,8 @@ static void nsim_queue_uninit(struct net
 	struct net_device *dev = ns->netdev;
 	int i;
 
+	if (!ns->rq)
+		return;
 	for (i = 0; i < dev->num_rx_queues; i++)
 		nsim_queue_free(dev, ns->rq[i]);
 
--