syzbot


general protection fault in __rt6_nh_dev_match

Status: premoderation: reported on 2025/05/13 02:34
Reported-by: syzbot+010380ede743b110f244@syzkaller.appspotmail.com
First crash: 2d16h, last: 2d16h

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000020: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000100-0x0000000000000107]
CPU: 1 PID: 8675 Comm: syz.3.2407 Not tainted 5.10.237-syzkaller-00309-g7e2543346ff7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:__rt6_device_match net/ipv6/route.c:473 [inline]
RIP: 0010:__rt6_nh_dev_match+0x121/0x220 net/ipv6/route.c:497
Code: 74 08 48 89 df e8 4f aa a9 fd 48 8b 1b 31 ff 44 89 fe e8 32 be 6f fd 45 85 ff 74 40 48 81 c3 00 01 00 00 48 89 d8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 ce 00 00 00 8b 1b 89 df 44 89 fe e8 d6
RSP: 0018:ffffc90000df6578 EFLAGS: 00010202
RAX: 0000000000000020 RBX: 0000000000000100 RCX: 0000000000000002
RDX: ffff8881287b13c0 RSI: 000000000000000d RDI: 0000000000000000
RBP: ffffc90000df65b8 R08: dffffc0000000000 R09: ffffc90000df6720
R10: fffff520001bece8 R11: 1ffff920001bece4 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 000000000000000d
FS:  00007fc906bc96c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000126426000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 nexthop_for_each_fib6_nh+0xf6/0x1e0 net/ipv4/nexthop.c:602
 rt6_nh_dev_match net/ipv6/route.c:517 [inline]
 rt6_device_match net/ipv6/route.c:546 [inline]
 ip6_pol_route_lookup+0x5bb/0x17d0 net/ipv6/route.c:1220
 pol_lookup_func include/net/ip6_fib.h:594 [inline]
 __fib6_rule_action net/ipv6/fib6_rules.c:232 [inline]
 fib6_rule_action+0x1c7/0x710 net/ipv6/fib6_rules.c:270
 fib_rules_lookup+0x489/0x8d0 net/core/fib_rules.c:318
 fib6_rule_lookup+0x179/0x560 net/ipv6/fib6_rules.c:107
 rt6_lookup+0x116/0x1d0 net/ipv6/route.c:1279
 ip6_tnl_link_config+0x443/0x9c0 net/ipv6/ip6_tunnel.c:1507
 ip6_tnl_dev_init+0x46e/0x640 net/ipv6/ip6_tunnel.c:1937
 register_netdevice+0x351/0x13c0 net/core/dev.c:9986
 ip6_tnl_create2+0xc2/0x360 net/ipv6/ip6_tunnel.c:290
 ip6_tnl_newlink+0x391/0x710 net/ipv6/ip6_tunnel.c:2080
 __rtnl_newlink net/core/rtnetlink.c:3482 [inline]
 rtnl_newlink+0x11bd/0x1640 net/core/rtnetlink.c:3530
 rtnetlink_rcv_msg+0x9db/0xb90 net/core/rtnetlink.c:5610
 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2485
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5628
 netlink_unicast_kernel net/netlink/af_netlink.c:1307 [inline]
 netlink_unicast+0x87c/0xa40 net/netlink/af_netlink.c:1333
 netlink_sendmsg+0x88d/0xb30 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:652 [inline]
 __sock_sendmsg net/socket.c:664 [inline]
 ____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2376
 ___sys_sendmsg+0x1f0/0x260 net/socket.c:2430
 __sys_sendmsg net/socket.c:2459 [inline]
 __do_sys_sendmsg net/socket.c:2468 [inline]
 __se_sys_sendmsg net/socket.c:2466 [inline]
 __x64_sys_sendmsg+0x1e2/0x2a0 net/socket.c:2466
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fc9085a2969
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:00007fc906bc9038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fc9087ca160 RCX: 00007fc9085a2969
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007fc908624ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fc9087ca160 R15: 00007ffc50f5b918
Modules linked in:
---[ end trace 5f852ca734ace620 ]---
RIP: 0010:__rt6_device_match net/ipv6/route.c:473 [inline]
RIP: 0010:__rt6_nh_dev_match+0x121/0x220 net/ipv6/route.c:497
Code: 74 08 48 89 df e8 4f aa a9 fd 48 8b 1b 31 ff 44 89 fe e8 32 be 6f fd 45 85 ff 74 40 48 81 c3 00 01 00 00 48 89 d8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 ce 00 00 00 8b 1b 89 df 44 89 fe e8 d6
RSP: 0018:ffffc90000df6578 EFLAGS: 00010202
RAX: 0000000000000020 RBX: 0000000000000100 RCX: 0000000000000002
RDX: ffff8881287b13c0 RSI: 000000000000000d RDI: 0000000000000000
RBP: ffffc90000df65b8 R08: dffffc0000000000 R09: ffffc90000df6720
R10: fffff520001bece8 R11: 1ffff920001bece4 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 000000000000000d
FS:  00007fc906bc96c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000126426000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	74 08                	je     0xa
   2:	48 89 df             	mov    %rbx,%rdi
   5:	e8 4f aa a9 fd       	call   0xfda9aa59
   a:	48 8b 1b             	mov    (%rbx),%rbx
   d:	31 ff                	xor    %edi,%edi
   f:	44 89 fe             	mov    %r15d,%esi
  12:	e8 32 be 6f fd       	call   0xfd6fbe49
  17:	45 85 ff             	test   %r15d,%r15d
  1a:	74 40                	je     0x5c
  1c:	48 81 c3 00 01 00 00 	add    $0x100,%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 20       	movzbl (%rax,%r12,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 ce 00 00 00    	jne    0x105
  37:	8b 1b                	mov    (%rbx),%ebx
  39:	89 df                	mov    %ebx,%edi
  3b:	44 89 fe             	mov    %r15d,%esi
  3e:	e8                   	.byte 0xe8
  3f:	d6                   	(bad)

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/13 02:33 android13-5.10-lts 7e2543346ff7 f6671af7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in __rt6_nh_dev_match
* Struck through repros no longer work on HEAD.