------------[ cut here ]------------
Have pending ack frames!
WARNING: CPU: 0 PID: 48 at net/mac80211/main.c:1389 ieee80211_free_ack_frame+0x3d/0x50 net/mac80211/main.c:1389
Modules linked in:
CPU: 0 PID: 48 Comm: kworker/u4:2 Not tainted 5.12.0-rc4-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+0x3d/0x50 net/mac80211/main.c:1389
Code: 99 d5 90 f8 48 89 df e8 81 75 9f fe 31 c0 5b c3 e8 88 d5 90 f8 c6 05 27 59 ba 04 01 48 c7 c7 a0 32 f3 8a 31 c0 e8 73 bb 5f f8 <0f> 0b eb d6 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 55 41 57
RSP: 0018:ffffc90000f0fb08 EFLAGS: 00010246

RAX: bf0bbce1c3733200 RBX: ffff88802327d140 RCX: ffff888011850000
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffff8880327366b0 R08: ffffffff8160abb2 R09: ffffed1017385fe8
R10: ffffed1017385fe8 R11: 0000000000000000 R12: dffffc0000000000
R13: 1ffff920001e1f68 R14: dffffc0000000000 R15: 1ffff920001e1f67
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f067517a000 CR3: 000000002bfe1000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 idr_for_each+0x15d/0x250 lib/idr.c:208
 ieee80211_free_hw+0xc1/0x3c0 net/mac80211/main.c:1405
 mac80211_hwsim_del_radio+0x27e/0x3e0 drivers/net/wireless/mac80211_hwsim.c:3435
 hwsim_exit_net+0x553/0x5e0 drivers/net/wireless/mac80211_hwsim.c:4187
 ops_exit_list net/core/net_namespace.c:175 [inline]
 cleanup_net+0x708/0xbd0 net/core/net_namespace.c:595
 process_one_work+0x789/0xfd0 kernel/workqueue.c:2275
 worker_thread+0xac1/0x1300 kernel/workqueue.c:2421
 kthread+0x39a/0x3c0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294