bisecting fixing commit since c3038e718a19fc596f7b1baba0f83d5146dc7784
building syzkaller on d0686497a9ccb558957ad69ffc9577dd80031b29
testing commit c3038e718a19fc596f7b1baba0f83d5146dc7784 with gcc (GCC) 8.1.0
kernel signature: 9ced0c235abbf30cac3511022fc72c7d0757984e
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: OK
testing current HEAD 312017a460d5ea31d646e7148e400e13db799ddc
testing commit 312017a460d5ea31d646e7148e400e13db799ddc with gcc (GCC) 8.1.0
kernel signature: ed1969b367890e50f900cfe24800b99310a97415
all runs: crashed: general protection fault in find_match
revisions tested: 2, total time: 34m54.639167935s (build: 16m40.462180695s, test: 17m46.433815424s)
the crash still happens on HEAD
commit msg: Linux 4.19.89
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: 0 PID: 29522 Comm: syz-executor.0 Not tainted 4.19.89-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
kobject: 'loop4' (0000000078e09db3): kobject_uevent_env
RIP: 0010:fib6_ignore_linkdown net/ipv6/route.c:655 [inline]
RIP: 0010:find_match+0x119/0xd90 net/ipv6/route.c:671
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:ffff888093c7ef58 EFLAGS: 00010207
kobject: 'loop4' (0000000078e09db3): fill_kobj_path: path = '/devices/virtual/block/loop4'
RAX: dffffc0000000000 RBX: ffff888083535d00 RCX: ffff888083535dc0
RDX: 0000000000000047 RSI: ffffffff87f982a0 RDI: 000000000000023c
RBP: ffff888093c7efd0 R08: 0000000000000000 R09: ffffed1015d44732
R10: ffffed1015d44732 R11: 0000000000000000 R12: ffff888093c7f0c0
R13: 0000000000000003 R14: ffff888093c7f080 R15: ffff888083535db0
FS:  00007f87d3034700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000075c000 CR3: 000000009f2c7000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
kobject: 'loop4' (0000000078e09db3): kobject_uevent_env
Call Trace:
 find_rr_leaf net/ipv6/route.c:717 [inline]
 rt6_select net/ipv6/route.c:767 [inline]
 fib6_table_lookup+0x39b/0x960 net/ipv6/route.c:1874
 ip6_pol_route+0x15a/0xa80 net/ipv6/route.c:1907
kobject: 'loop4' (0000000078e09db3): fill_kobj_path: path = '/devices/virtual/block/loop4'
kobject: 'loop4' (0000000078e09db3): kobject_uevent_env
 ip6_pol_route_output+0x3c/0x70 net/ipv6/route.c:2133
kobject: 'loop4' (0000000078e09db3): fill_kobj_path: path = '/devices/virtual/block/loop4'
 fib6_rule_lookup+0x104/0x480 net/ipv6/fib6_rules.c:118
 ip6_route_output_flags+0x22a/0x2c0 net/ipv6/route.c:2161
 ip6_dst_lookup_tail+0x450/0x1620 net/ipv6/ip6_output.c:979
 ip6_dst_lookup_flow+0x9b/0x1e0 net/ipv6/ip6_output.c:1080
kobject: 'loop4' (0000000078e09db3): kobject_uevent_env
 ip6_sk_dst_lookup_flow+0x4c6/0xb20 net/ipv6/ip6_output.c:1118
kobject: 'loop4' (0000000078e09db3): fill_kobj_path: path = '/devices/virtual/block/loop4'
 udpv6_sendmsg+0x1437/0x2be0 net/ipv6/udp.c:1383
 inet_sendmsg+0x108/0x440 net/ipv4/af_inet.c:798
kobject: 'loop4' (0000000078e09db3): kobject_uevent_env
 sock_sendmsg_nosec net/socket.c:622 [inline]
 sock_sendmsg+0xb5/0xf0 net/socket.c:632
 ___sys_sendmsg+0x28e/0x950 net/socket.c:2115
kobject: 'loop4' (0000000078e09db3): fill_kobj_path: path = '/devices/virtual/block/loop4'
 __sys_sendmmsg+0x160/0x370 net/socket.c:2210
kobject: 'loop4' (0000000078e09db3): kobject_uevent_env
 __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
kobject: 'loop4' (0000000078e09db3): fill_kobj_path: path = '/devices/virtual/block/loop4'
 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:00007f87d3033c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000459ef9
RDX: 00000000000000c6 RSI: 0000000020006d00 RDI: 0000000000000004
kobject: 'loop4' (0000000078e09db3): kobject_uevent_env
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f87d30346d4
R13: 00000000004c7ab9 R14: 00000000004dd908 R15: 00000000ffffffff
Modules linked in:
---[ end trace c4da6634a672b1bb ]---
RIP: 0010:fib6_ignore_linkdown net/ipv6/route.c:655 [inline]
RIP: 0010:find_match+0x119/0xd90 net/ipv6/route.c:671
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:ffff888093c7ef58 EFLAGS: 00010207
RAX: dffffc0000000000 RBX: ffff888083535d00 RCX: ffff888083535dc0
kobject: 'loop4' (0000000078e09db3): fill_kobj_path: path = '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000c858bb57): kobject_uevent_env
kobject: 'loop5' (00000000c858bb57): fill_kobj_path: path = '/devices/virtual/block/loop5'
kobject: 'loop2' (000000003fe599ee): kobject_uevent_env
kobject: 'loop2' (000000003fe599ee): fill_kobj_path: path = '/devices/virtual/block/loop2'
RDX: 0000000000000047 RSI: ffffffff87f982a0 RDI: 000000000000023c
kobject: 'loop3' (0000000092a6f656): kobject_uevent_env
RBP: ffff888093c7efd0 R08: 0000000000000000 R09: ffffed1015d44732
kobject: 'loop3' (0000000092a6f656): fill_kobj_path: path = '/devices/virtual/block/loop3'
R10: ffffed1015d44732 R11: 0000000000000000 R12: ffff888093c7f0c0
kobject: 'loop1' (000000009878b9d4): kobject_uevent_env
kobject: 'loop1' (000000009878b9d4): fill_kobj_path: path = '/devices/virtual/block/loop1'
R13: 0000000000000003 R14: ffff888093c7f080 R15: ffff888083535db0
FS:  00007f87d3034700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4775443000 CR3: 000000009f2c7000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400