syzbot


general protection fault in ip6_pol_route

Status: premoderation: reported on 2025/11/10 08:09
Reported-by: syzbot+facf852df7a80f91dd04@syzkaller.appspotmail.com
First crash: 14d, last: 14d
Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in ip6_pol_route (2) net 19 C done unreliable 9 1304d 1739d 0/29 auto-obsoleted due to no activity on 2022/09/19 15:39
upstream general protection fault in ip6_pol_route (2) net 8 15 517d 523d 0/29 auto-obsoleted due to no activity on 2024/08/28 04:33
upstream general protection fault in ip6_pol_route net 8 73 524d 562d 26/29 fixed on 2024/06/18 11:11
upstream general protection fault in ip6_pol_route (3) net 8 syz error 25 166d 293d 0/29 auto-obsoleted due to no activity on 2025/09/19 08:31
linux-5.15 KASAN: use-after-free Read in ip6_pol_route 19 1 608d 608d 0/3 auto-obsoleted due to no activity on 2024/07/04 16:14
upstream Internal error in ip6_pol_route net 2 2 744d 768d 0/29 auto-obsoleted due to no activity on 2024/02/18 23:43

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000013: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]
CPU: 1 UID: 0 PID: 3316 Comm: syz.4.947 Not tainted syzkaller #0 0b5ffdee5fcd2f7749818d1ff954e9c21353764e
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:rt6_get_pcpu_route net/ipv6/route.c:1445 [inline]
RIP: 0010:ip6_pol_route+0x484/0x12c0 net/ipv6/route.c:2299
Code: 8b 03 65 48 8b 18 31 ff 48 89 de e8 a6 55 9f fc 48 85 db 0f 84 c0 00 00 00 49 89 dc 48 81 c3 98 00 00 00 48 89 d8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 2f 0c 00 00 8b 1b 31 ff 89 de e8 d4 54
RSP: 0018:ffffc90009d66320 EFLAGS: 00010202
RAX: 0000000000000013 RBX: 0000000000000099 RCX: ffff888115e71300
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90009d664b8 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90009d66410 R11: fffff520013acc86 R12: 0000000000000001
R13: dffffc0000000000 R14: ffffffff84e6adac R15: dffffc0000000000
FS:  00007ff1e87d26c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff1e87b0f98 CR3: 000000011c4d8000 CR4: 00000000003526b0
DR0: 0000000000000002 DR1: 0000000000000006 DR2: 0000000000000003
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ip6_pol_route_output+0x55/0x80 net/ipv6/route.c:2641
 pol_lookup_func include/net/ip6_fib.h:626 [inline]
 fib6_rule_lookup+0x1d8/0x6b0 net/ipv6/fib6_rules.c:117
 ip6_route_output_flags_noref net/ipv6/route.c:2674 [inline]
 ip6_route_output_flags+0x2a3/0x480 net/ipv6/route.c:2686
 ip6_route_output include/net/ip6_route.h:93 [inline]
 icmpv6_rt_has_prefsrc+0x4a/0x210 net/ipv6/icmp.c:246
 icmp6_send+0xb29/0x1630 net/ipv6/icmp.c:565
 __icmpv6_send include/linux/icmpv6.h:28 [inline]
 icmpv6_send include/linux/icmpv6.h:49 [inline]
 ip6_link_failure+0x89/0x330 net/ipv6/route.c:2834
 dst_link_failure include/net/dst.h:429 [inline]
 vti_xmit net/ipv4/ip_vti.c:271 [inline]
 vti_tunnel_xmit+0xd38/0x1640 net/ipv4/ip_vti.c:307
 __netdev_start_xmit include/linux/netdevice.h:4975 [inline]
 netdev_start_xmit include/linux/netdevice.h:4984 [inline]
 xmit_one net/core/dev.c:3674 [inline]
 dev_hard_start_xmit+0x21b/0x770 net/core/dev.c:3690
 __dev_queue_xmit+0x19cc/0x3790 net/core/dev.c:4526
 dev_queue_xmit include/linux/netdevice.h:3141 [inline]
 neigh_connected_output+0x470/0x510 net/core/neighbour.c:1594
 neigh_output include/net/neighbour.h:550 [inline]
 ip6_finish_output2+0x11bb/0x1990 net/ipv6/ip6_output.c:141
 __ip6_finish_output net/ipv6/ip6_output.c:215 [inline]
 ip6_finish_output+0x54e/0xb40 net/ipv6/ip6_output.c:226
 NF_HOOK_COND include/linux/netfilter.h:306 [inline]
 ip6_output+0x1d5/0x3c0 net/ipv6/ip6_output.c:247
 dst_output include/net/dst.h:459 [inline]
 ip6_local_out+0x23a/0x4a0 net/ipv6/output_core.c:155
 ip6_send_skb+0xba/0x1d0 net/ipv6/ip6_output.c:1968
 udp_v6_send_skb+0xbc3/0x1740 net/ipv6/udp.c:1348
 udpv6_sendmsg+0x1cfb/0x27b0 net/ipv6/udp.c:1645
 inet6_sendmsg+0xef/0x120 net/ipv6/af_inet6.c:666
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x5db/0xa70 net/socket.c:2610
 ___sys_sendmsg+0x220/0x2a0 net/socket.c:2664
 __sys_sendmmsg+0x271/0x470 net/socket.c:2750
 __do_sys_sendmmsg net/socket.c:2779 [inline]
 __se_sys_sendmmsg net/socket.c:2776 [inline]
 __x64_sys_sendmmsg+0xa4/0xc0 net/socket.c:2776
 x64_sys_call+0xfec/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:308
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7ff1e798f6c9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff1e87d2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007ff1e7be5fa0 RCX: 00007ff1e798f6c9
RDX: 0000000000000002 RSI: 0000200000000400 RDI: 0000000000000003
RBP: 00007ff1e7a11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000004044800 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff1e7be6038 R14: 00007ff1e7be5fa0 R15: 00007fff676f8f58
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:rt6_get_pcpu_route net/ipv6/route.c:1445 [inline]
RIP: 0010:ip6_pol_route+0x484/0x12c0 net/ipv6/route.c:2299
Code: 8b 03 65 48 8b 18 31 ff 48 89 de e8 a6 55 9f fc 48 85 db 0f 84 c0 00 00 00 49 89 dc 48 81 c3 98 00 00 00 48 89 d8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 2f 0c 00 00 8b 1b 31 ff 89 de e8 d4 54
RSP: 0018:ffffc90009d66320 EFLAGS: 00010202
RAX: 0000000000000013 RBX: 0000000000000099 RCX: ffff888115e71300
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90009d664b8 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90009d66410 R11: fffff520013acc86 R12: 0000000000000001
R13: dffffc0000000000 R14: ffffffff84e6adac R15: dffffc0000000000
FS:  00007ff1e87d26c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff1e87b0f98 CR3: 000000011c4d8000 CR4: 00000000003526b0
DR0: 0000000000000002 DR1: 0000000000000006 DR2: 0000000000000003
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	8b 03                	mov    (%rbx),%eax
   2:	65 48 8b 18          	mov    %gs:(%rax),%rbx
   6:	31 ff                	xor    %edi,%edi
   8:	48 89 de             	mov    %rbx,%rsi
   b:	e8 a6 55 9f fc       	call   0xfc9f55b6
  10:	48 85 db             	test   %rbx,%rbx
  13:	0f 84 c0 00 00 00    	je     0xd9
  19:	49 89 dc             	mov    %rbx,%r12
  1c:	48 81 c3 98 00 00 00 	add    $0x98,%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 28       	movzbl (%rax,%r13,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 2f 0c 00 00    	jne    0xc66
  37:	8b 1b                	mov    (%rbx),%ebx
  39:	31 ff                	xor    %edi,%edi
  3b:	89 de                	mov    %ebx,%esi
  3d:	e8                   	.byte 0xe8
  3e:	d4                   	(bad)
  3f:	54                   	push   %rsp

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/10 08:08 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust general protection fault in ip6_pol_route
* Struck through repros no longer work on HEAD.