bisecting fixing commit since 4fccc2503536a564a4ba31a1d50439854201659f building syzkaller on 2c36e7a75f8689b3da20e1a81a2ee5391f3af6e5 testing commit 4fccc2503536a564a4ba31a1d50439854201659f with gcc (GCC) 8.4.1 20210217 kernel signature: fd553421ea543531e89410ec94724e35a83d6871687debc5e290014c70bee794 all runs: crashed: general protection fault in macvlan_hard_header testing current HEAD 1e986fe9ad15b8406034c504afc5ae76f0a8e852 testing commit 1e986fe9ad15b8406034c504afc5ae76f0a8e852 with gcc (GCC) 8.4.1 20210217 kernel signature: 4acbfaa512c9d75546416f8046a46f566a5a16060e93afce35a7449b6f16178e all runs: crashed: general protection fault in macvlan_hard_header revisions tested: 2, total time: 29m34.794306067s (build: 22m14.6250782s, test: 6m45.845245414s) the crash still happens on HEAD commit msg: Linux 4.19.191 crash: general protection fault in macvlan_hard_header IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access team0: Device macvtap0 is up. Set it down before adding it as a team port general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 3396 Comm: systemd-udevd Not tainted 4.19.191-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:dev_hard_header include/linux/netdevice.h:2883 [inline] RIP: 0010:macvlan_hard_header+0x7e/0x190 drivers/net/macvlan.c:593 Code: c1 ee 03 80 3c 06 00 0f 85 82 00 00 00 4c 8b a3 20 02 00 00 4d 85 e4 74 3a 48 b8 00 00 00 00 00 fc ff df 4c 89 e6 48 c1 ee 03 <80> 3c 06 00 0f 85 b3 00 00 00 49 8b 04 24 48 85 c0 74 16 48 89 de RSP: 0000:ffff8881f69077e8 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffffffff895b3420 RCX: ffff8881e61bb3b8 RDX: 00000000000086dd RSI: 00000006e0044006 RDI: ffffffff895b3640 RBP: ffff8881f6907828 R08: ffff8881d4d71210 R09: 0000000000000038 IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready R10: 1ffff1103ce4dab6 R11: 0000000000000000 R12: 0000003700220037 IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready R13: ffff8881e5098840 R14: ffff8881e5098840 R15: ffff8881e61bb240 FS: 00007fcaf0aac8c0(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000562364e1a140 CR3: 00000001dc594004 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dev_hard_header include/linux/netdevice.h:2886 [inline] neigh_resolve_output net/core/neighbour.c:1369 [inline] neigh_resolve_output+0x46c/0x810 net/core/neighbour.c:1354 neigh_output include/net/neighbour.h:501 [inline] ip6_finish_output2+0x8f6/0x2200 net/ipv6/ip6_output.c:120 ip6_finish_output+0x3c8/0xd20 net/ipv6/ip6_output.c:192 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip6_output+0x1bf/0x660 net/ipv6/ip6_output.c:209 dst_output include/net/dst.h:455 [inline] NF_HOOK include/linux/netfilter.h:289 [inline] ndisc_send_skb+0xcc8/0x12d0 net/ipv6/ndisc.c:491 ndisc_send_rs+0x116/0x5e0 net/ipv6/ndisc.c:685 addrconf_rs_timer+0x25c/0x5e0 net/ipv6/addrconf.c:3835 call_timer_fn+0x14c/0x510 kernel/time/timer.c:1338 expire_timers kernel/time/timer.c:1375 [inline] __run_timers kernel/time/timer.c:1696 [inline] __run_timers kernel/time/timer.c:1664 [inline] run_timer_softirq+0xb63/0x1180 kernel/time/timer.c:1709 __do_softirq+0x25f/0x919 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x17f/0x1c0 kernel/softirq.c:412 IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready exiting_irq arch/x86/include/asm/apic.h:535 [inline] smp_apic_timer_interrupt+0x13e/0x540 arch/x86/kernel/apic/apic.c:1098 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0033:0x7fcaef8a7140 Code: c7 85 94 fa ff ff 00 00 00 00 89 9d a4 fa ff ff e9 45 92 ff ff 0f 1f 44 00 00 31 c9 e9 f9 8c ff ff 66 0f 1f 84 00 00 00 00 00 <48> 81 ec d8 00 00 00 84 c0 48 89 54 24 30 48 89 4c 24 38 4c 89 44 RSP: 002b:00007fff6f112d08 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000000 RBX: 00007fcaf0aac710 RCX: 0000000000000000 RDX: 00007fff6f112d20 RSI: 000056236324165a RDI: 0000562364e277e0 RBP: 0000562364e277e0 R08: 0000562364e23620 R09: 0000000000000000 R10: 0000000000080000 R11: 0000000000000246 R12: 0000562364e191d0 R13: 000000006324a701 R14: 0000562364e14650 R15: 0000000000000001 Modules linked in: ---[ end trace 9cc872f7267ed677 ]--- RIP: 0010:dev_hard_header include/linux/netdevice.h:2883 [inline] RIP: 0010:macvlan_hard_header+0x7e/0x190 drivers/net/macvlan.c:593 Code: c1 ee 03 80 3c 06 00 0f 85 82 00 00 00 4c 8b a3 20 02 00 00 4d 85 e4 74 3a 48 b8 00 00 00 00 00 fc ff df 4c 89 e6 48 c1 ee 03 <80> 3c 06 00 0f 85 b3 00 00 00 49 8b 04 24 48 85 c0 74 16 48 89 de RSP: 0000:ffff8881f69077e8 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffffffff895b3420 RCX: ffff8881e61bb3b8 RDX: 00000000000086dd RSI: 00000006e0044006 RDI: ffffffff895b3640 RBP: ffff8881f6907828 R08: ffff8881d4d71210 R09: 0000000000000038 R10: 1ffff1103ce4dab6 R11: 0000000000000000 R12: 0000003700220037 R13: ffff8881e5098840 R14: ffff8881e5098840 R15: ffff8881e61bb240 FS: 00007fcaf0aac8c0(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000562364e1a140 CR3: 00000001dc594004 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400