bisecting fixing commit since 6dd0e32665e591e9debe3edaf73c2f8135bf047e
building syzkaller on 17a986e54c507287c078a70fa9eea0be9f191f84
testing commit 6dd0e32665e591e9debe3edaf73c2f8135bf047e with gcc (GCC) 8.1.0
kernel signature: 8fdc11ee64d2de5f65baedb70f0dee1622d87a5e110aec56e767c68fed31c00b
all runs: crashed: WARNING in bpf_warn_invalid_xdp_action
testing current HEAD dce0f88600e49746b4bda873965b671a23ff4313
testing commit dce0f88600e49746b4bda873965b671a23ff4313 with gcc (GCC) 8.1.0
kernel signature: 5fdf72f8f8505a5ff7357230c04a9d94f4199d97d15b9c8a4b7f7daa1ac4c1c3
all runs: crashed: WARNING in bpf_warn_invalid_xdp_action
revisions tested: 2, total time: 24m50.030958796s (build: 17m44.107029169s, test: 6m29.429946478s)
the crash still happens on HEAD
commit msg: Linux 4.19.132
crash: WARNING in bpf_warn_invalid_xdp_action
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0
------------[ cut here ]------------
batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
Illegal XDP return value 2658060181, expect packet loss!
IPv6: ADDRCONF(NETDEV_UP): batadv_slave_0: link is not ready
WARNING: CPU: 1 PID: 18 at net/core/filter.c:5539 bpf_warn_invalid_xdp_action+0x38/0x40 net/core/filter.c:5537
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 18 Comm: ksoftirqd/1 Not tainted 4.19.132-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x123/0x177 lib/dump_stack.c:118
 panic+0x1cd/0x375 kernel/panic.c:186
batman_adv: batadv0: Interface activated: batadv_slave_0
 __warn.cold.8+0x1b/0x3e kernel/panic.c:541
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1
batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
 report_bug+0x1a4/0x200 lib/bug.c:186
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x200/0x350 arch/x86/kernel/traps.c:296
batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038
RIP: 0010:bpf_warn_invalid_xdp_action+0x38/0x40 net/core/filter.c:5537
Code: c7 c0 60 56 c0 87 55 89 fa 48 c7 c6 20 56 c0 87 48 89 e5 48 c7 c7 a0 56 c0 87 c6 05 48 b2 ae 03 01 48 0f 46 f0 e8 5b 85 cb fb <0f> 0b 5d c3 0f 1f 40 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5
RSP: 0018:ffff8880a9867ae0 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff88808e4bd346 RCX: 0000000000000000
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1
RDX: 0000000000000004 RSI: ffffffff87678f00 RDI: ffffffff8a189960
RBP: ffff8880a9867ae0 R08: ffffed1015d65079 R09: ffffed1015d65078
R10: ffffed1015d65078 R11: ffff8880aeb283c7 R12: dffffc0000000000
R13: ffff8880a9867be0 R14: ffff88808e4bd280 R15: ffff88808d0f716e
 veth_xdp_rcv_skb drivers/net/veth.c:551 [inline]
 veth_xdp_rcv drivers/net/veth.c:602 [inline]
 veth_poll+0xfea/0x2e50 drivers/net/veth.c:622
 napi_poll net/core/dev.c:6271 [inline]
 net_rx_action+0x470/0xe20 net/core/dev.c:6337
 __do_softirq+0x260/0x92d kernel/softirq.c:292
 run_ksoftirqd+0x94/0x100 kernel/softirq.c:653
 smpboot_thread_fn+0x55f/0x8a0 kernel/smpboot.c:164
 kthread+0x324/0x3e0 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Kernel Offset: disabled
Rebooting in 86400 seconds..