bisecting fixing commit since 4fccc2503536a564a4ba31a1d50439854201659f building syzkaller on 2c36e7a75f8689b3da20e1a81a2ee5391f3af6e5 testing commit 4fccc2503536a564a4ba31a1d50439854201659f with gcc (GCC) 8.1.0 kernel signature: 91a3fb538188b099e69a0b4b00f09f03d8015125a0aa5f37495dab6a9e7207b8 all runs: crashed: general protection fault in macvlan_hard_header testing current HEAD b3a99fd385fab59d0b8b4fdfb449c1e979accab8 testing commit b3a99fd385fab59d0b8b4fdfb449c1e979accab8 with gcc (GCC) 8.1.0 kernel signature: 16ad0fb6f19989251f44112ad448fc40b69f1db0e8ca5fd40dfbf565e07ca9e8 all runs: crashed: general protection fault in macvlan_hard_header revisions tested: 2, total time: 24m23.071759484s (build: 16m50.348618168s, test: 6m34.831877059s) the crash still happens on HEAD commit msg: Linux 4.19.129 crash: general protection fault in macvlan_hard_header IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready kasan: CONFIG_KASAN_INLINE enabled IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.19.129-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:2890 [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: 0018:ffff8880aea077e0 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffffffff895b63e0 RCX: ffff88809f6edcb8 RDX: 00000000000086dd RSI: 0007200700000006 RDI: ffffffff895b6600 RBP: ffff8880aea07820 R08: ffff8880944b9190 R09: 0000000000000038 R10: 1ffff1101387faf6 R11: 0000000000000000 R12: 0039003800000037 R13: ffff888095d3b2c0 R14: ffff888095d3b2c0 R15: ffff88809f6edb40 FS: 0000000000000000(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0620f7e028 CR3: 00000000a4248000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dev_hard_header include/linux/netdevice.h:2893 [inline] neigh_resolve_output+0x46c/0x810 net/core/neighbour.c:1369 neigh_output include/net/neighbour.h:501 [inline] ip6_finish_output2+0x8f6/0x2200 net/ipv6/ip6_output.c:120 ip6_finish_output+0x3c4/0xa90 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip6_output+0x1bf/0x660 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:447 [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:3834 call_timer_fn+0x14c/0x510 kernel/time/timer.c:1326 expire_timers kernel/time/timer.c:1363 [inline] __run_timers kernel/time/timer.c:1684 [inline] run_timer_softirq+0xb63/0x1180 kernel/time/timer.c:1697 __do_softirq+0x260/0x92d kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x17f/0x1c0 kernel/softirq.c:412 exiting_irq arch/x86/include/asm/apic.h:544 [inline] smp_apic_timer_interrupt+0x13e/0x540 arch/x86/kernel/apic/apic.c:1094 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0010:do_idle+0x0/0x560 kernel/sched/idle.c:225 Code: fa 48 c1 ea 03 80 3c 02 00 75 15 48 83 3d 7f d3 0d 07 00 74 09 fb 66 0f 1f 44 00 00 5d c3 0f 0b e8 a5 f0 4d 00 eb e4 0f 1f 00 <55> 48 89 e5 41 57 48 8d 85 78 ff ff ff 41 56 48 c1 e8 03 41 55 49 RSP: 0018:ffffffff88407db0 EFLAGS: 00000292 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000000 RBX: 37c9111ba2d62200 RCX: 1ffffffff1080fa4 RDX: 1ffff11015d459a1 RSI: 0000000000000001 RDI: ffff8880aea2cd08 RBP: ffffffff88407e38 R08: ffffed1015d45851 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: ffffffff88479e40 R14: 00000000000000c7 R15: 0000000000000000 rest_init+0x193/0x199 init/main.c:441 start_kernel+0x6aa/0x6e6 init/main.c:737 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490 x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:471 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 Modules linked in: ---[ end trace de4eec49248e9a98 ]--- RIP: 0010:dev_hard_header include/linux/netdevice.h:2890 [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: 0018:ffff8880aea077e0 EFLAGS: 00010207 IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready RAX: dffffc0000000000 RBX: ffffffff895b63e0 RCX: ffff88809f6edcb8 RDX: 00000000000086dd RSI: 0007200700000006 RDI: ffffffff895b6600 RBP: ffff8880aea07820 R08: ffff8880944b9190 R09: 0000000000000038 R10: 1ffff1101387faf6 R11: 0000000000000000 R12: 0039003800000037 IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready R13: ffff888095d3b2c0 R14: ffff888095d3b2c0 R15: ffff88809f6edb40 FS: 0000000000000000(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0620f7e028 CR3: 00000000a4248000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400