[syzbot ci] Re: netfilter: flowtable: tear down HW offloaded flows on FIB route changes

[syzbot ci]

syzbot ci has tested the following series

[v1] netfilter: flowtable: tear down HW offloaded flows on FIB route changes
https://lore.kernel.org/all/20260708205404....@gmail.com
* [PATCH nf] netfilter: flowtable: tear down HW offloaded flows on FIB route changes

and found the following issue:
general protection fault in net_generic

Full report is available here:
https://ci.syzbot.org/series/75cd5a68-8e8e-41ef-9da6-dea3554407a7

***

general protection fault in net_generic

tree: nf
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/netfilter/nf.git
base: 60444706aa17616efc03190d099ac347e28b3d0a
arch: amd64
compiler: Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
config: https://ci.syzbot.org/builds/b941607c-6459-4d25-8127-6c11f2a37ef0/config
syz repro: https://ci.syzbot.org/findings/93de0afd-01d4-4d54-9d3f-13094335f314/syz_repro

Oops: general protection fault, probably for non-canonical address 0xdffffc00000002c8: 0000 [#1] SMP KASAN PTI
KASAN: probably user-memory-access in range [0x0000000000001640-0x0000000000001647]
CPU: 1 UID: 0 PID: 5813 Comm: syz.2.19 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:net_generic+0xd4/0x240 include/net/netns/generic.h:46
Code: 8c be 4a 03 00 00 48 c7 c2 c0 83 e0 8c e8 14 1b 09 f8 49 bf 00 00 00 00 00 fc ff df 49 81 c6 40 16 00 00 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 0d a4 9a f8 4d 8b 26 e8 45 e8 1b
RSP: 0018:ffffc90003bde998 EFLAGS: 00010202
RAX: 00000000000002c8 RBX: ffffffff8999417e RCX: ffff8881699c5940
RDX: 0000000000000000 RSI: ffffffff8c2ab760 RDI: ffffffff8c2ab720
RBP: 0000000000000005 R08: ffffffff8999417e R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8e959c20 R12: ffff8881b1679870
R13: dffffc0000000000 R14: 0000000000001640 R15: dffffc0000000000
FS: 00007ff6de31c6c0(0000) GS:ffff8882a921d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff6dd272780 CR3: 000000016bc8e000 CR4: 00000000000006f0
Call Trace:
<TASK>
fib_seq_sum+0x29/0x280 net/core/fib_notifier.c:43
register_fib_notifier+0x49/0x360 net/core/fib_notifier.c:106
nf_flow_table_init+0x34a/0x460 net/netfilter/nf_flow_table_core.c:888
tcf_ct_flow_table_get+0x13b6/0x1f40 net/sched/act_ct.c:352
tcf_ct_init+0x6bd/0xb10 net/sched/act_ct.c:1423
tcf_action_init_1+0x4ba/0x740 net/sched/act_api.c:1433
tcf_action_init+0x30e/0xb10 net/sched/act_api.c:1508
tcf_action_add net/sched/act_api.c:2106 [inline]
tc_ctl_action+0x43b/0xc70 net/sched/act_api.c:2163
rtnetlink_rcv_msg+0x7b9/0xc00 net/core/rtnetlink.c:7085
netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775
__sock_sendmsg net/socket.c:790 [inline]
____sys_sendmsg+0x54e/0x850 net/socket.c:2684
___sys_sendmsg+0x2a5/0x360 net/socket.c:2738
__sys_sendmsg net/socket.c:2770 [inline]
__do_sys_sendmsg net/socket.c:2775 [inline]
__se_sys_sendmsg net/socket.c:2773 [inline]
__x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff6dd39ce59
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:00007ff6de31c028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff6dd615fa0 RCX: 00007ff6dd39ce59
RDX: 0000000000000040 RSI: 0000200000000080 RDI: 0000000000000003
RBP: 00007ff6dd432e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff6dd616038 R14: 00007ff6dd615fa0 R15: 00007ffd83f8d058
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:net_generic+0xd4/0x240 include/net/netns/generic.h:46
Code: 8c be 4a 03 00 00 48 c7 c2 c0 83 e0 8c e8 14 1b 09 f8 49 bf 00 00 00 00 00 fc ff df 49 81 c6 40 16 00 00 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 0d a4 9a f8 4d 8b 26 e8 45 e8 1b
RSP: 0018:ffffc90003bde998 EFLAGS: 00010202
RAX: 00000000000002c8 RBX: ffffffff8999417e RCX: ffff8881699c5940
RDX: 0000000000000000 RSI: ffffffff8c2ab760 RDI: ffffffff8c2ab720
RBP: 0000000000000005 R08: ffffffff8999417e R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8e959c20 R12: ffff8881b1679870
R13: dffffc0000000000 R14: 0000000000001640 R15: dffffc0000000000
FS: 00007ff6de31c6c0(0000) GS:ffff8882a921d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff6dd3ea540 CR3: 000000016bc8e000 CR4: 00000000000006f0
----------------
Code disassembly (best guess):
0: 8c be 4a 03 00 00 mov %?,0x34a(%rsi)
6: 48 c7 c2 c0 83 e0 8c mov $0xffffffff8ce083c0,%rdx
d: e8 14 1b 09 f8 call 0xf8091b26
12: 49 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%r15
19: fc ff df
1c: 49 81 c6 40 16 00 00 add $0x1640,%r14
23: 4c 89 f0 mov %r14,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 4c 89 f7 mov %r14,%rdi
34: e8 0d a4 9a f8 call 0xf89aa446
39: 4d 8b 26 mov (%r14),%r12
3c: e8 .byte 0xe8
3d: 45 rex.RB
3e: e8 .byte 0xe8
3f: 1b .byte 0x1b


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
Tested-by: syz...@syzkaller.appspotmail.com

---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzk...@googlegroups.com.

To test a patch for this bug, please reply with `#syz test`
(should be on a separate line).

The patch should be attached to the email.
Note: arguments like custom git repos and branches are not supported.