------------[ cut here ]------------ Have pending ack frames! WARNING: CPU: 0 PID: 8952 at net/mac80211/main.c:1400 ieee80211_free_ack_frame+0x48/0x50 net/mac80211/main.c:1400 Modules linked in: CPU: 0 PID: 8952 Comm: kworker/u4:1 Not tainted 5.12.0-rc4-next-20210326-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:1400 Code: e8 ad d7 17 f9 48 89 ef e8 f5 64 a2 fe 31 c0 5b 5d c3 e8 9b d7 17 f9 48 c7 c7 a0 42 86 8a c6 05 5e ac 56 05 01 e8 db d7 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:ffffc9000354f9d8 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff888023cab900 RSI: ffffffff815c3fd5 RDI: fffff520006a9f2d RBP: ffff88803eb72140 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff815bd77e R11: 0000000000000000 R12: dffffc0000000000 R13: ffffffff885c5100 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5a911b8000 CR3: 0000000013955000 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/0x2b0 net/mac80211/main.c:1416 mac80211_hwsim_del_radio drivers/net/wireless/mac80211_hwsim.c:3435 [inline] hwsim_exit_net+0x5bc/0xc90 drivers/net/wireless/mac80211_hwsim.c:4187 ops_exit_list+0xb0/0x160 net/core/net_namespace.c:175 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:595 process_one_work+0x98d/0x1600 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:294