syzbot


general protection fault in nexthop_get_nhc_lookup

Status: premoderation: reported on 2025/07/09 23:30
Reported-by: syzbot+08dfae76b29663915743@syzkaller.appspotmail.com
First crash: 65d, last: 1d15h
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-1 general protection fault in nexthop_get_nhc_lookup 2 8 7d20h 35d 0/2 premoderation: reported on 2025/08/09 17:13

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc000000005b: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000002d8-0x00000000000002df]
CPU: 0 PID: 6783 Comm: syz.3.2223 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2025
RIP: 0010:ip_ignore_linkdown include/linux/inetdevice.h:254 [inline]
RIP: 0010:fib_lookup_good_nhc net/ipv4/fib_trie.c:1363 [inline]
RIP: 0010:nexthop_get_nhc_lookup+0x1a2/0x6c0 include/net/nexthop.h:291
Code: 74 08 48 89 df e8 0e 6f bf fd 48 89 5d a8 48 8b 1b b8 d8 02 00 00 48 01 c3 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 e0 6e bf fd 48 8b 1b 48 85 db 74 68
RSP: 0018:ffffc900013c70d8 EFLAGS: 00010202
RAX: 000000000000005b RBX: 00000000000002d8 RCX: dffffc0000000000
RDX: ffff8881307e8000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900013c7148 R08: dffffc0000000000 R09: ffffc900013c7340
R10: fffff52000278e6e R11: 1ffff92000278e68 R12: ffff88812f0cd300
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8881125a5390
FS:  00007fcf094676c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c29a1e1 CR3: 00000001154ce000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 fib_table_lookup+0xe4c/0x1730 net/ipv4/fib_trie.c:1542
 fib_lookup include/net/ip_fib.h:379 [inline]
 ip_route_output_key_hash_rcu+0x49e/0x20e0 net/ipv4/route.c:2674
 ip_route_output_key_hash+0x123/0x1c0 net/ipv4/route.c:2564
 __ip_route_output_key include/net/route.h:126 [inline]
 vti6_xmit net/ipv6/ip6_vti.c:463 [inline]
 vti6_tnl_xmit+0xc95/0x15c0 net/ipv6/ip6_vti.c:584
 __netdev_start_xmit include/linux/netdevice.h:4864 [inline]
 netdev_start_xmit include/linux/netdevice.h:4878 [inline]
 xmit_one net/core/dev.c:3608 [inline]
 dev_hard_start_xmit+0x244/0x670 net/core/dev.c:3624
 __dev_queue_xmit+0x1446/0x2540 net/core/dev.c:4210
 dev_queue_xmit+0x17/0x20 net/core/dev.c:4243
 __bpf_tx_skb net/core/filter.c:2129 [inline]
 __bpf_redirect_no_mac net/core/filter.c:2163 [inline]
 __bpf_redirect+0x699/0xe30 net/core/filter.c:2186
 ____bpf_clone_redirect net/core/filter.c:2470 [inline]
 bpf_clone_redirect+0x242/0x380 net/core/filter.c:2442
 bpf_prog_6893982b85ceadf7+0x56/0x6d0
 bpf_dispatcher_nop_func include/linux/bpf.h:669 [inline]
 bpf_test_run+0x310/0x9b0 net/bpf/test_run.c:116
 bpf_prog_test_run_skb+0x9c2/0x10b0 net/bpf/test_run.c:635
 bpf_prog_test_run+0x350/0x3c0 kernel/bpf/syscall.c:3156
 __do_sys_bpf kernel/bpf/syscall.c:4453 [inline]
 __se_sys_bpf+0x49f/0x680 kernel/bpf/syscall.c:4391
 __x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:4391
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fcf0a9feba9
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:00007fcf09467038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007fcf0ac45fa0 RCX: 00007fcf0a9feba9
RDX: 000000000000002c RSI: 0000200000000080 RDI: 000000000000000a
RBP: 00007fcf0aa81e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcf0ac46038 R14: 00007fcf0ac45fa0 R15: 00007fffd7fe3f58
Modules linked in:
---[ end trace c145ea48e7838ed6 ]---
RIP: 0010:ip_ignore_linkdown include/linux/inetdevice.h:254 [inline]
RIP: 0010:fib_lookup_good_nhc net/ipv4/fib_trie.c:1363 [inline]
RIP: 0010:nexthop_get_nhc_lookup+0x1a2/0x6c0 include/net/nexthop.h:291
Code: 74 08 48 89 df e8 0e 6f bf fd 48 89 5d a8 48 8b 1b b8 d8 02 00 00 48 01 c3 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 e0 6e bf fd 48 8b 1b 48 85 db 74 68
RSP: 0018:ffffc900013c70d8 EFLAGS: 00010202
RAX: 000000000000005b RBX: 00000000000002d8 RCX: dffffc0000000000
RDX: ffff8881307e8000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900013c7148 R08: dffffc0000000000 R09: ffffc900013c7340
R10: fffff52000278e6e R11: 1ffff92000278e68 R12: ffff88812f0cd300
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8881125a5390
FS:  00007fcf094676c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c29a1e1 CR3: 00000001154ce000 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 0e 6f bf fd       	call   0xfdbf6f18
   a:	48 89 5d a8          	mov    %rbx,-0x58(%rbp)
   e:	48 8b 1b             	mov    (%rbx),%rbx
  11:	b8 d8 02 00 00       	mov    $0x2d8,%eax
  16:	48 01 c3             	add    %rax,%rbx
  19:	48 89 d8             	mov    %rbx,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	48 89 df             	mov    %rbx,%rdi
  33:	e8 e0 6e bf fd       	call   0xfdbf6f18
  38:	48 8b 1b             	mov    (%rbx),%rbx
  3b:	48 85 db             	test   %rbx,%rbx
  3e:	74 68                	je     0xa8

Crashes (15):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/12 04:40 android13-5.10-lts 43931d9f8738 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
2025/09/11 20:18 android13-5.10-lts 43931d9f8738 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
2025/09/10 01:10 android13-5.10-lts 48647f2c6800 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
2025/09/08 17:52 android13-5.10-lts 48647f2c6800 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
2025/09/04 09:04 android13-5.10-lts dce613ec61e0 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
2025/08/30 04:55 android13-5.10-lts 1154f779f3f3 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
2025/08/18 00:41 android13-5.10-lts 1154f779f3f3 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
2025/08/17 15:42 android13-5.10-lts 1154f779f3f3 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
2025/07/24 11:42 android13-5.10-lts ad9a98ef27a4 65d60d73 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
2025/07/22 11:36 android13-5.10-lts ad9a98ef27a4 1555463b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
2025/07/16 07:23 android13-5.10-lts 6de38b5f6c2b 124ec9cc .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
2025/07/15 03:41 android13-5.10-lts d0d90e085c21 03fcfc4b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
2025/07/11 17:31 android13-5.10-lts 59e9a7228857 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
2025/07/10 02:48 android13-5.10-lts 59e9a7228857 956bd956 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
2025/07/09 23:29 android13-5.10-lts 59e9a7228857 f4e5e155 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in nexthop_get_nhc_lookup
* Struck through repros no longer work on HEAD.