bisecting fixing commit since c3038e718a19fc596f7b1baba0f83d5146dc7784 building syzkaller on d0686497a9ccb558957ad69ffc9577dd80031b29 testing commit c3038e718a19fc596f7b1baba0f83d5146dc7784 with gcc (GCC) 8.4.1 20210217 kernel signature: d9320bcc07eddebb0b70e805dd1516aa87a832f6ebc9285ae73096ba1a034771 run #0: crashed: general protection fault in find_match run #1: crashed: general protection fault in find_match run #2: crashed: general protection fault in find_match run #3: crashed: general protection fault in find_match run #4: crashed: general protection fault in find_match run #5: crashed: general protection fault in find_match run #6: crashed: general protection fault in find_match run #7: crashed: general protection fault in find_match run #8: crashed: general protection fault in find_match run #9: crashed: general protection fault in find_match run #10: crashed: general protection fault in find_match run #11: crashed: general protection fault in find_match run #12: crashed: general protection fault in find_match run #13: crashed: general protection fault in find_match run #14: crashed: general protection fault in find_match run #15: crashed: general protection fault in find_match run #16: crashed: kernel panic: Fatal exception run #17: crashed: general protection fault in find_match run #18: OK run #19: OK testing current HEAD 1e986fe9ad15b8406034c504afc5ae76f0a8e852 testing commit 1e986fe9ad15b8406034c504afc5ae76f0a8e852 with gcc (GCC) 8.4.1 20210217 kernel signature: 21a577ec34fc1e326d16f462595fd281222ce349b2eeb712e2b8574c70087a12 all runs: crashed: general protection fault in find_match revisions tested: 2, total time: 50m26.433376049s (build: 26m54.540921354s, test: 22m21.479054531s) the crash still happens on HEAD commit msg: Linux 4.19.191 crash: general protection fault in find_match bond0 (unregistering): Releasing backup interface bond_slave_0 bond0 (unregistering): Released all slaves 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: 1 PID: 1206 Comm: syz-executor275 Not tainted 4.19.191-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:fib6_ignore_linkdown net/ipv6/route.c:657 [inline] RIP: 0010:find_match+0x119/0xd90 net/ipv6/route.c:673 Code: 4d c0 84 c0 4c 8b 45 b8 44 8b 5d b0 0f 84 1b 05 00 00 49 8d b8 3c 02 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 e8 RSP: 0018:ffff8881e84cef90 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffff8881da4f5d00 RCX: ffff8881da4f5dc0 RDX: 0000000000000047 RSI: ffffffff88197f60 RDI: 000000000000023c RBP: ffff8881e84cf008 R08: 0000000000000000 R09: ffffed103ed24732 R10: ffffed103ed24732 R11: 0000000000000000 R12: ffff8881e84cf100 R13: 0000000000000003 R14: ffff8881e84cf0c0 R15: ffff8881da4f5db0 FS: 00007f7e32d76700(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd19959a10 CR3: 00000001e8a0d001 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: find_rr_leaf net/ipv6/route.c:719 [inline] rt6_select net/ipv6/route.c:769 [inline] fib6_table_lookup+0x39b/0xae0 net/ipv6/route.c:1876 ip6_pol_route+0x14b/0x8f0 net/ipv6/route.c:1909 ip6_pol_route_output+0x3c/0x70 net/ipv6/route.c:2135 fib6_rule_lookup+0x104/0x480 net/ipv6/fib6_rules.c:118 ip6_route_output_flags+0x22a/0x2c0 net/ipv6/route.c:2163 ip6_dst_lookup_tail+0x450/0x1620 net/ipv6/ip6_output.c:1017 ip6_dst_lookup_flow+0x83/0x170 net/ipv6/ip6_output.c:1118 ip6_sk_dst_lookup_flow net/ipv6/ip6_output.c:1156 [inline] ip6_sk_dst_lookup_flow+0x4e9/0xb50 net/ipv6/ip6_output.c:1146 udpv6_sendmsg+0x1472/0x2bf0 net/ipv6/udp.c:1386 inet_sendmsg+0x108/0x440 net/ipv4/af_inet.c:798 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xb5/0xf0 net/socket.c:632 ___sys_sendmsg+0x28e/0x950 net/socket.c:2115 __sys_sendmmsg+0x160/0x370 net/socket.c:2210 __do_sys_sendmmsg net/socket.c:2239 [inline] __se_sys_sendmmsg net/socket.c:2236 [inline] __x64_sys_sendmmsg+0x98/0x100 net/socket.c:2236 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x446ff9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 a1 15 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f7e32d76318 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00000000004cc4f8 RCX: 0000000000446ff9 RDX: 00000000000000c6 RSI: 0000000020006d00 RDI: 0000000000000004 RBP: 00000000004cc4f0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000049c324 R13: 00007ffd199444df R14: 00007f7e32d76400 R15: 0000000000022000 Modules linked in: ---[ end trace 3b78391cbfdf3d66 ]--- RIP: 0010:fib6_ignore_linkdown net/ipv6/route.c:657 [inline] RIP: 0010:find_match+0x119/0xd90 net/ipv6/route.c:673 Code: 4d c0 84 c0 4c 8b 45 b8 44 8b 5d b0 0f 84 1b 05 00 00 49 8d b8 3c 02 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 e8 RSP: 0018:ffff8881e84cef90 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffff8881da4f5d00 RCX: ffff8881da4f5dc0 RDX: 0000000000000047 RSI: ffffffff88197f60 RDI: 000000000000023c RBP: ffff8881e84cf008 R08: 0000000000000000 R09: ffffed103ed24732 R10: ffffed103ed24732 R11: 0000000000000000 R12: ffff8881e84cf100 R13: 0000000000000003 R14: ffff8881e84cf0c0 R15: ffff8881da4f5db0 FS: 00007f7e32d76700(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd19959a10 CR3: 00000001e8a0d005 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400