bisecting fixing commit since 4fccc2503536a564a4ba31a1d50439854201659f building syzkaller on 2c36e7a75f8689b3da20e1a81a2ee5391f3af6e5 testing commit 4fccc2503536a564a4ba31a1d50439854201659f with gcc (GCC) 8.1.0 kernel signature: 54846c90a46df87f0d5afe473e61164ca212d6ea081abf7c7c4dfdb0654a9044 all runs: crashed: general protection fault in macvlan_hard_header testing current HEAD 20b3a3dfdf6c55b50bbdc8e231a3dbf6bf965dc7 testing commit 20b3a3dfdf6c55b50bbdc8e231a3dbf6bf965dc7 with gcc (GCC) 8.1.0 kernel signature: 31c65f36f85922e9fa43f54b93c3459ec5c7fdedbac22494c3f0fe08d99f83d3 all runs: crashed: general protection fault in macvlan_hard_header revisions tested: 2, total time: 26m33.063816606s (build: 19m5.357996763s, test: 6m29.451476408s) the crash still happens on HEAD commit msg: Linux 4.19.134 crash: general protection fault in macvlan_hard_header IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready netlink: 8 bytes leftover after parsing attributes in process `syz-executor.1'. kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 8234 Comm: syz-executor.1 Not tainted 4.19.134-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:2882 [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: 00010202 RAX: dffffc0000000000 RBX: ffffffff895b73e0 RCX: ffff88809405bc78 RDX: 00000000000086dd RSI: 0007200000070004 RDI: ffffffff895b7600 RBP: ffff8880aea07820 R08: ffff888099584490 R09: 0000000000000038 R10: 1ffff11012c115e6 R11: 0000000000000000 R12: 0039000000380023 R13: ffff888072407040 R14: ffff888072407040 R15: ffff88809405bb00 FS: 00007f5d3ab84700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000559646755920 CR3: 0000000095264000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dev_hard_header include/linux/netdevice.h:2885 [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+0x3c6/0xa90 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: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:3834 call_timer_fn+0x14c/0x510 kernel/time/timer.c:1337 expire_timers kernel/time/timer.c:1374 [inline] __run_timers kernel/time/timer.c:1695 [inline] run_timer_softirq+0xb63/0x1180 kernel/time/timer.c:1708 __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:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline] RIP: 0010:console_unlock+0x904/0xde0 kernel/printk/printk.c:2465 Code: 00 fc ff df 48 89 f8 48 c1 e8 03 42 80 3c 18 00 0f 85 96 03 00 00 48 83 3d e0 f9 03 07 00 0f 84 08 02 00 00 48 8b 7d c8 57 9d <0f> 1f 44 00 00 e9 5d f8 ff ff 49 8d 7e 08 48 89 f8 48 c1 e8 03 42 RSP: 0018:ffff888082116e48 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff10a40b9 RBX: 0000000000000200 RCX: 1ffff11012e16da2 RDX: 0000000000000000 RSI: ffff8880970b6cf0 RDI: 0000000000000282 RBP: ffff888082116ec0 R08: ffff8880970b6d10 R09: 0000000000000000 R10: 0000000000000000 R11: dffffc0000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff88c16440 R15: ffffffff88c16410 vprintk_emit+0x191/0x540 kernel/printk/printk.c:1965 vprintk_default+0x1a/0x20 kernel/printk/printk.c:2007 vprintk_func+0x49/0x12c kernel/printk/printk_safe.c:397 printk+0x9a/0xc0 kernel/printk/printk.c:2040 nla_parse.cold.11+0x1f/0x30 lib/nlattr.c:267 nlmsg_parse include/net/netlink.h:398 [inline] rtnl_newlink+0x1e2/0x1320 net/core/rtnetlink.c:2953 rtnetlink_rcv_msg+0x34f/0x8f0 net/core/rtnetlink.c:4777 netlink_rcv_skb+0x13e/0x3d0 net/netlink/af_netlink.c:2455 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:4795 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x443/0x650 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x765/0xc40 net/netlink/af_netlink.c:1909 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xb5/0xf0 net/socket.c:632 ___sys_sendmsg+0x647/0x950 net/socket.c:2115 __sys_sendmsg+0xd9/0x180 net/socket.c:2153 __do_sys_sendmsg net/socket.c:2162 [inline] __se_sys_sendmsg net/socket.c:2160 [inline] __x64_sys_sendmsg+0x73/0xb0 net/socket.c:2160 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c4a9 Code: 2d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f5d3ab83c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f5d3ab846d4 RCX: 000000000045c4a9 RDX: 0000000000000084 RSI: 0000000020000140 RDI: 0000000000000005 RBP: 000000000076bfc0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000009f9 R14: 00000000004cc75a R15: 000000000076bfcc Modules linked in: ---[ end trace 6223d322506c55dd ]--- RIP: 0010:dev_hard_header include/linux/netdevice.h:2882 [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: 00010202 RAX: dffffc0000000000 RBX: ffffffff895b73e0 RCX: ffff88809405bc78 RDX: 00000000000086dd RSI: 0007200000070004 RDI: ffffffff895b7600 RBP: ffff8880aea07820 R08: ffff888099584490 R09: 0000000000000038 R10: 1ffff11012c115e6 R11: 0000000000000000 R12: 0039000000380023 R13: ffff888072407040 R14: ffff888072407040 R15: ffff88809405bb00 FS: 00007f5d3ab84700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000559646755920 CR3: 0000000095264000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400