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general protection fault in fib6_nh_get_excptn_bucket (4)

Status: closed as invalid on 2026/04/08 13:02
Subsystems: net
[Documentation on labels]
First crash: 90d, last: 90d
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in fib6_nh_get_excptn_bucket net 2 1 347d 347d 0/29 closed as invalid on 2025/07/11 15:16
upstream general protection fault in fib6_nh_get_excptn_bucket (3) net 2 3 156d 181d 0/29 closed as invalid on 2026/02/18 04:33
upstream general protection fault in fib6_nh_get_excptn_bucket (2) net 2 1 259d 259d 0/29 closed as invalid on 2025/09/29 07:16
upstream KASAN: slab-out-of-bounds Read in fib6_nh_get_excptn_bucket (3) net 17 2 1834d 1883d 0/29 auto-closed as invalid on 2021/09/13 13:28

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067]
CPU: 2 UID: 0 PID: 14178 Comm: syz.4.2295 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:fib6_nh_get_excptn_bucket+0x11f/0x1e0 net/ipv6/route.c:1673
Code: 05 75 00 8a 06 01 e8 30 bc ac f7 e9 2e ff ff ff e8 a6 e5 d0 f7 48 8d 7b 60 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 a7 00 00 00 48 8b 5b 60 e8 8e b5 57 01 31 ff 89
RSP: 0018:ffffc90004a9f340 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90025b81000
RDX: 000000000000000c RSI: ffffffff8a37b9ba RDI: 0000000000000060
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: fffff52000953e96 R14: 1ffff92000953e97 R15: dffffc0000000000
FS:  00007fb05b2026c0(0000) GS:ffff8880d654a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb05a5ae9c0 CR3: 0000000038fe1000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000007800 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rt6_find_cached_rt+0x151/0x280 net/ipv6/route.c:1871
 ip6_pol_route+0x238/0x1230 net/ipv6/route.c:2289
 pol_lookup_func include/net/ip6_fib.h:617 [inline]
 fib6_rule_lookup+0x386/0x720 net/ipv6/fib6_rules.c:125
 ip6_route_output_flags_noref net/ipv6/route.c:2697 [inline]
 ip6_route_output_flags+0x1d0/0x650 net/ipv6/route.c:2709
 ip6_dst_lookup_tail.constprop.0+0x116/0x2110 net/ipv6/ip6_output.c:1156
 ip6_dst_lookup_flow+0x99/0x1d0 net/ipv6/ip6_output.c:1259
 rawv6_sendmsg+0xe61/0x4750 net/ipv6/raw.c:894
 inet_sendmsg+0x11c/0x140 net/ipv4/af_inet.c:859
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 sock_write_iter+0x509/0x610 net/socket.c:1195
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1070 fs/read_write.c:688
 ksys_write+0x1f8/0x250 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb05a39c629
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb05b202028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fb05a616090 RCX: 00007fb05a39c629
RDX: 00000000000005ac RSI: 00002000000000c0 RDI: 000000000000000a
RBP: 00007fb05a432b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb05a616128 R14: 00007fb05a616090 R15: 00007ffe24357008
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:fib6_nh_get_excptn_bucket+0x11f/0x1e0 net/ipv6/route.c:1673
Code: 05 75 00 8a 06 01 e8 30 bc ac f7 e9 2e ff ff ff e8 a6 e5 d0 f7 48 8d 7b 60 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 a7 00 00 00 48 8b 5b 60 e8 8e b5 57 01 31 ff 89
RSP: 0018:ffffc90004a9f340 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90025b81000
RDX: 000000000000000c RSI: ffffffff8a37b9ba RDI: 0000000000000060
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: fffff52000953e96 R14: 1ffff92000953e97 R15: dffffc0000000000
FS:  00007fb05b2026c0(0000) GS:ffff8880d654a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffeee74f818 CR3: 0000000038fe1000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000007800 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 6 bytes skipped:
   0:	e8 30 bc ac f7       	call   0xf7acbc35
   5:	e9 2e ff ff ff       	jmp    0xffffff38
   a:	e8 a6 e5 d0 f7       	call   0xf7d0e5b5
   f:	48 8d 7b 60          	lea    0x60(%rbx),%rdi
  13:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  1a:	fc ff df
  1d:	48 89 fa             	mov    %rdi,%rdx
  20:	48 c1 ea 03          	shr    $0x3,%rdx
* 24:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  28:	0f 85 a7 00 00 00    	jne    0xd5
  2e:	48 8b 5b 60          	mov    0x60(%rbx),%rbx
  32:	e8 8e b5 57 01       	call   0x157b5c5
  37:	31 ff                	xor    %edi,%edi
  39:	89                   	.byte 0x89

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/24 08:19 upstream 7dff99b35460 41d2fa6a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in fib6_nh_get_excptn_bucket
* Struck through repros no longer work on HEAD.