Hello, syzbot found the following issue on: HEAD commit: 89d714ab6043 Merge tag 'linux-watchdog-5.16-rc1' of git://.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=108e7c3eb00000 kernel config: https://syzkaller.appspot.com/x/.config?x=dcce4e862d74e466 dashboard link: https://syzkaller.appspot.com/bug?extid=ac648b0525be1feba506 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ac648b0525be1feba506@xxxxxxxxxxxxxxxxxxxxxxxxx netdevsim netdevsim1 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0 netdevsim netdevsim1 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0 netdevsim netdevsim1 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0 ------------[ cut here ]------------ Have pending ack frames! WARNING: CPU: 0 PID: 10 at net/mac80211/main.c:1419 ieee80211_free_ack_frame+0x48/0x50 net/mac80211/main.c:1419 Modules linked in: CPU: 0 PID: 10 Comm: kworker/u4:1 Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:ieee80211_free_ack_frame+0x48/0x50 net/mac80211/main.c:1419 Code: e8 0d dc f3 f8 48 89 ef e8 d5 c6 97 fe 31 c0 5b 5d c3 e8 fb db f3 f8 48 c7 c7 00 9b ab 8a c6 05 b3 00 d8 04 01 e8 89 e9 72 00 <0f> 0b eb d2 0f 1f 40 00 41 57 41 56 49 89 f6 41 55 41 54 49 89 d4 RSP: 0018:ffffc90000f0f9d8 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff888011c3c280 RSI: ffffffff815e6b88 RDI: fffff520001e1f2d RBP: ffff8880781a6000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff815e095e R11: 0000000000000000 R12: dffffc0000000000 R13: ffffffff888320f0 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055c247c48cf0 CR3: 0000000021d96000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> idr_for_each+0x113/0x220 lib/idr.c:208 ieee80211_free_hw+0x9b/0x2b0 net/mac80211/main.c:1435 mac80211_hwsim_del_radio drivers/net/wireless/mac80211_hwsim.c:3586 [inline] hwsim_exit_net+0x55f/0xca0 drivers/net/wireless/mac80211_hwsim.c:4346 ops_exit_list+0xb0/0x160 net/core/net_namespace.c:168 cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:593 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 </TASK> --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.