bisecting fixing commit since f69d02e37a85645aa90d18cacfff36dba370f797 building syzkaller on 06ed56cd22e24a55c40d152880b66b108834c8f2 testing commit f69d02e37a85645aa90d18cacfff36dba370f797 with gcc (GCC) 10.2.1 20210217 kernel signature: aa7d4ad725f000c35c1c8e33689f2d93709166b07fa13410ce1e6ec6817bf8b4 all runs: crashed: WARNING in carl9170_usb_submit_cmd_urb/usb_submit_urb testing current HEAD 9ccce092fc64d19504fa54de4fd659e279cc92e7 testing commit 9ccce092fc64d19504fa54de4fd659e279cc92e7 with gcc (GCC) 10.2.1 20210217 kernel signature: 94a48bec86a5d3bb5f11899f03bac9e3b6db7795b28418f31ba4c2bd763a8a1d run #0: basic kernel testing failed: WARNING in __nf_unregister_net_hook run #1: basic kernel testing failed: WARNING in __nf_unregister_net_hook run #2: basic kernel testing failed: WARNING in __nf_unregister_net_hook run #3: basic kernel testing failed: WARNING in __nf_unregister_net_hook run #4: basic kernel testing failed: WARNING in __nf_unregister_net_hook run #5: basic kernel testing failed: WARNING in __nf_unregister_net_hook run #6: basic kernel testing failed: WARNING in __nf_unregister_net_hook run #7: crashed: WARNING in __nf_unregister_net_hook run #8: crashed: WARNING in __nf_unregister_net_hook run #9: crashed: WARNING in __nf_unregister_net_hook revisions tested: 2, total time: 21m18.132139234s (build: 13m53.084668989s, test: 6m31.479425958s) the crash still happens on HEAD commit msg: Merge tag 'for-linus-5.13-ofs-1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux crash: WARNING in __nf_unregister_net_hook ------------[ cut here ]------------ hook not found, pf 3 num 0 WARNING: CPU: 1 PID: 40 at net/netfilter/core.c:480 __nf_unregister_net_hook+0x17a/0x560 net/netfilter/core.c:480 Modules linked in: CPU: 0 PID: 40 Comm: kworker/u4:2 Not tainted 5.12.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:__nf_unregister_net_hook+0x17a/0x560 net/netfilter/core.c:480 Code: 89 f0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 a7 03 00 00 8b 53 1c 44 89 e6 48 c7 c7 00 c9 9d 89 4c 89 04 24 e8 37 83 62 01 <0f> 0b 4c 8b 04 24 e9 ba 00 00 00 48 89 ea 48 c1 e2 04 49 8d 7c 10 RSP: 0018:ffffc90000eefbf0 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff888144912a00 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000004 RDI: fffff520001ddf70 RBP: 0000000000000001 R08: 0000000000000001 R09: ffff8880ba11fa5b R10: ffffed1017423f4b R11: 0000000000000001 R12: 0000000000000003 R13: ffff888029110000 R14: ffff888144912a1c R15: ffff888029110f20 FS: 0000000000000000(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2f6e0ab000 CR3: 0000000012df4000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: nf_unregister_net_hook net/netfilter/core.c:502 [inline] nf_unregister_net_hooks+0xb1/0xf0 net/netfilter/core.c:576 ops_pre_exit_list net/core/net_namespace.c:165 [inline] cleanup_net+0x3a4/0x990 net/core/net_namespace.c:583 process_one_work+0x84c/0x13b0 kernel/workqueue.c:2275 worker_thread+0x598/0xf80 kernel/workqueue.c:2421 kthread+0x36f/0x450 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294