------------[ cut here ]------------
Have pending ack frames!
WARNING: CPU: 0 PID: 8689 at net/mac80211/main.c:1384 ieee80211_free_ack_frame+0x48/0x50 net/mac80211/main.c:1384
Modules linked in:
CPU: 0 PID: 8689 Comm: kworker/u4:3 Not tainted 5.11.0-rc7-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:1384
Code: e8 1d ab 25 f9 48 89 ef e8 25 b2 a5 fe 31 c0 5b 5d c3 e8 0b ab 25 f9 48 c7 c7 c0 5b 62 8a c6 05 72 76 42 05 01 e8 32 70 6d 00 <0f> 0b eb d2 0f 1f 40 00 41 57 41 56 41 55 49 89 d5 41 54 49 89 f4
RSP: 0018:ffffc900021e79d8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88801eb76300 RSI: ffffffff815b7455 RDI: fffff5200043cf2d
RBP: ffff8880127c5000 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815b05fe R11: 0000000000000000 R12: dffffc0000000000
R13: ffffffff884d2b90 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff0b0be7000 CR3: 000000001dcfe000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 idr_for_each+0x113/0x220 lib/idr.c:208
 ieee80211_free_hw+0x9b/0x2a0 net/mac80211/main.c:1400
 mac80211_hwsim_del_radio drivers/net/wireless/mac80211_hwsim.c:3363 [inline]
 hwsim_exit_net+0x5bc/0xc90 drivers/net/wireless/mac80211_hwsim.c:4115
 ops_exit_list+0xb0/0x160 net/core/net_namespace.c:187
 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:604
 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296