bisecting fixing commit since 12cd844a39ed16aa183a820a54fe6f9a0bb4cd14
building syzkaller on 749688d22abef3f3cb9a0480e15c19a3f2ed8e13
testing commit 12cd844a39ed16aa183a820a54fe6f9a0bb4cd14 with gcc (GCC) 8.1.0
kernel signature: b4dd9b6e87e5891a1d3357aeed0ec5add53f9c307654b4b434064efe0ef22e75
all runs: crashed: WARNING in ipvlan_unregister_nf_hook
testing current HEAD 050272a0423e68207fd2367831ae610680129062
testing commit 050272a0423e68207fd2367831ae610680129062 with gcc (GCC) 8.1.0
kernel signature: c5771e2301768333da515b66eaac5153ade8beb0b8ccf1628cc623eeb5dbc88e
all runs: crashed: WARNING in ipvlan_unregister_nf_hook
revisions tested: 2, total time: 25m41.019946788s (build: 17m46.076050925s, test: 6m28.750381414s)
the crash still happens on HEAD
commit msg: Linux 4.14.177
crash: WARNING in ipvlan_unregister_nf_hook
veth1_macvtap: Device is already in use.
hsr_slave_1: Device is already in use.
device hsr_slave_0 left promiscuous mode
syz-executor.2 (8466) used greatest stack depth: 23944 bytes left
------------[ cut here ]------------
WARNING: CPU: 1 PID: 8547 at drivers/net/ipvlan/ipvlan_main.c:63 net_generic include/net/netns/generic.h:45 [inline]
WARNING: CPU: 1 PID: 8547 at drivers/net/ipvlan/ipvlan_main.c:63 ipvlan_unregister_nf_hook+0x1df/0x210 drivers/net/ipvlan/ipvlan_main.c:61
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 8547 Comm: syz-executor.4 Not tainted 4.14.177-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xf7/0x13b lib/dump_stack.c:58
 panic+0x1b0/0x358 kernel/panic.c:183
 __warn.cold.8+0x25/0x2c kernel/panic.c:547
 report_bug+0x1a4/0x1f3 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:177 [inline]
 do_error_trap+0x1bd/0x310 arch/x86/kernel/traps.c:295
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:963
RIP: 0010:ipvlan_unregister_nf_hook+0x1df/0x210 drivers/net/ipvlan/ipvlan_main.c:63
RSP: 0018:ffff8880824072a8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88808ecbc240 RCX: 1ffff110117f7557
RDX: 0000000000000004 RSI: 0000000000000002 RDI: 0000000000000286
RBP: ffff8880824072c0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000028 R11: ffff88808bfba240 R12: ffff888093a64100
R13: ffff888093fea940 R14: ffff88808eda1348 R15: 0000000000000000
 ipvlan_set_port_mode+0x404/0x520 drivers/net/ipvlan/ipvlan_main.c:104
 ipvlan_link_new+0xb19/0x1000 drivers/net/ipvlan/ipvlan_main.c:616
 rtnl_newlink+0xbdd/0x1390 net/core/rtnetlink.c:2728
 rtnetlink_rcv_msg+0x34c/0x9e0 net/core/rtnetlink.c:4315
 netlink_rcv_skb+0x133/0x370 net/netlink/af_netlink.c:2433
 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:4327
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x40b/0x600 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x730/0xbd0 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0xf0 net/socket.c:656
 ___sys_sendmsg+0x625/0x920 net/socket.c:2062
 __sys_sendmsg+0xc1/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0xd/0x20 net/socket.c:2103
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c849
RSP: 002b:00007fefe8897c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fefe88986d4 RCX: 000000000045c849
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000005
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000009f9 R14: 00000000004ccb17 R15: 000000000076bf0c
Kernel Offset: disabled
Rebooting in 86400 seconds..