bisecting fixing commit since c3038e718a19fc596f7b1baba0f83d5146dc7784 building syzkaller on d0686497a9ccb558957ad69ffc9577dd80031b29 testing commit c3038e718a19fc596f7b1baba0f83d5146dc7784 with gcc (GCC) 8.1.0 kernel signature: 1e4a94ecf07551e478179e537bd05be5da577dc6 all runs: crashed: general protection fault in find_match testing current HEAD cb1f9a169a0e197f93816ace48a6520e8640809d testing commit cb1f9a169a0e197f93816ace48a6520e8640809d with gcc (GCC) 8.1.0 kernel signature: b0bf300fbf5e9f3bc382228bd9ff6c9a82afc64b all runs: crashed: general protection fault in find_match revisions tested: 2, total time: 30m53.459496748s (build: 17m13.942295649s, test: 13m15.142766196s) the crash still happens on HEAD commit msg: Linux 4.19.94 crash: general protection fault in find_match 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: 692 Comm: syz-executor.2 Not tainted 4.19.94-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:ffff88809636ef58 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffff8880a81c67c0 RCX: ffff8880a81c6880 RDX: 0000000000000047 RSI: ffffffff87f98320 RDI: 000000000000023c RBP: ffff88809636efd0 R08: 0000000000000000 R09: ffffed1015d44732 R10: ffffed1015d44732 R11: 0000000000000000 R12: ffff88809636f0c0 R13: 0000000000000003 R14: ffff88809636f080 R15: ffff8880a81c6870 FS: 00007fdf829b5700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f62a9aa11c4 CR3: 000000009bcca000 CR4: 00000000001406e0 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/0x960 net/ipv6/route.c:1876 ip6_pol_route+0x15a/0xa80 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:979 ip6_dst_lookup_flow+0x9b/0x1e0 net/ipv6/ip6_output.c:1080 ip6_sk_dst_lookup_flow+0x4c6/0xb20 net/ipv6/ip6_output.c:1118 udpv6_sendmsg+0x1437/0x2be0 net/ipv6/udp.c:1383 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: 0033:0x459ef9 Code: ad 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fdf829b4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000459ef9 RDX: 00000000000000c6 RSI: 0000000020006d00 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fdf829b56d4 R13: 00000000004c7ab9 R14: 00000000004dd908 R15: 00000000ffffffff Modules linked in: kobject: 'loop3' (00000000045b26ef): kobject_uevent_env kobject: 'loop3' (00000000045b26ef): fill_kobj_path: path = '/devices/virtual/block/loop3' ---[ end trace f1100017e4bd9554 ]--- kobject: 'loop1' (00000000b75a0a83): kobject_uevent_env RIP: 0010:fib6_ignore_linkdown net/ipv6/route.c:657 [inline] RIP: 0010:find_match+0x119/0xd90 net/ipv6/route.c:673 kobject: 'loop1' (00000000b75a0a83): fill_kobj_path: path = '/devices/virtual/block/loop1' 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 kobject: 'loop3' (00000000045b26ef): kobject_uevent_env kobject: 'loop3' (00000000045b26ef): fill_kobj_path: path = '/devices/virtual/block/loop3' RSP: 0018:ffff88809636ef58 EFLAGS: 00010207 kobject: 'loop1' (00000000b75a0a83): kobject_uevent_env RAX: dffffc0000000000 RBX: ffff8880a81c67c0 RCX: ffff8880a81c6880 kobject: 'loop1' (00000000b75a0a83): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop3' (00000000045b26ef): kobject_uevent_env RDX: 0000000000000047 RSI: ffffffff87f98320 RDI: 000000000000023c kobject: 'loop3' (00000000045b26ef): fill_kobj_path: path = '/devices/virtual/block/loop3' kobject: 'loop1' (00000000b75a0a83): kobject_uevent_env kobject: 'loop1' (00000000b75a0a83): fill_kobj_path: path = '/devices/virtual/block/loop1' RBP: ffff88809636efd0 R08: 0000000000000000 R09: ffffed1015d44732 kobject: 'loop0' (00000000a445f051): kobject_uevent_env kobject: 'loop0' (00000000a445f051): fill_kobj_path: path = '/devices/virtual/block/loop0' R10: ffffed1015d44732 R11: 0000000000000000 R12: ffff88809636f0c0 kobject: 'loop4' (00000000a7f0e7b5): kobject_uevent_env kobject: 'loop4' (00000000a7f0e7b5): fill_kobj_path: path = '/devices/virtual/block/loop4' R13: 0000000000000003 R14: ffff88809636f080 R15: ffff8880a81c6870 FS: 00007fdf829b5700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd6b8c9a80 CR3: 000000009bcca000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400