[REGRESSION] 6.19.4 stable netfilter / nftables

From: Genes Lists

Date: Thu Feb 26 2026 - 22:52:13 EST


I have a problem with nftables not working on 6.19.4

I apologize for not having done a bisect, but this is on a production
firewall, so a bisect is not practical. If I can reproduce this on non-
prod box, I can do a bisect. Hopefully this is is helpful nonetheless.


Check different kernels with same nftables rules:

- 6.19.4 (freshly compiled)
nft fails, and kernel logs trace. 
boot does not complete if nftables service is enabled.

- 6.19.3
nft works fine and nothing bad in logs

- mainline commit 3f4a08e64442340f4807de63e30aef22cc308830
nft fails with same error, but no trace in the kernel log.
boots but without working nftables.

The error nft displays, references somewhere in the middle
of a large set of cidr elements:

nft: In file included from /etc/nftables.conf:134:2-44:
nft: ./etc/nftables.d/set_filter.conf:1746:7-21: Error:
Could not proces rule: File exists
nft: 23.157.184.0/23,
nft: ^^^^^^^^^^^^^^^

Removing all but one element from set and rerunning nft, 
moves the line number but the error remains.

Userspace Archlinux:
- nftables 1.1.6
- libmnl 1.0.5
- libnftnl 1.3.1
- gcc 15.2.1+r604+g0b99615a8aef-1
- binutils 2.46-1

The first sign of trouble in 6.19.4 kernel log is:

[ 39.731654] kernel: RIP: 0010:free_large_kmalloc+0xa8/0xd0
[ 39.731676] kernel: Code: 8d 78 ff a8 01 48 0f 44 fb eb bb 3d f8 00
00 00 75 18 0f 0b 80 3d 50 ff fd 01 00 0f 84 48 c1 b9 ff ba 00 f0 ff ff
31 ed eb 8d <0f> 0b 48 c7 c6 86 3c 83 96 48 89 df 5b 5d e9 95 9c fa ff
48 83 ef
[ 39.731698] kernel: RSP: 0018:ffffd0bcc146b610 EFLAGS: 00010202
[ 39.731720] kernel: RAX: 00000000000000ff RBX: fffffa5a04ad8680 RCX:
ffff89c66b61ad40
[ 39.731747] kernel: RDX: 0000000000000000 RSI: ffff89c66b61a880 RDI:
fffffa5a04ad8680
[ 39.731767] kernel: RBP: ffff89c66b61a880 R08: ffff89c6496ab6f0 R09:
ffff89c66b6229c1
[ 39.731787] kernel: R10: ffff89c66b61a880 R11: fffffa5a04ad8680 R12:
ffffd0bcc146b6a0
[ 39.731814] kernel: R13: ffff89c6496ab6f0 R14: ffff89c6496ab720 R15:
ffffd0bcc146b6b0
[ 39.731836] kernel: FS: 00007bd6c7717c40(0000)
GS:ffff89ca073c7000(0000) knlGS:0000000000000000
[ 39.731854] kernel: CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
[ 39.731877] kernel: CR2: 0000746430061058 CR3: 0000000105ce4004 CR4:
00000000003726f0
[ 39.731903] kernel: Call Trace:
[ 39.731926] kernel: <TASK>
[ 39.731993] kernel: nf_tables_abort_release+0x22f/0x260 [nf_tables
78d597f27a85e5d69246ce15656dd0568c927257]
[ 39.732026] kernel: nf_tables_abort+0x2cd/0xe80 [nf_tables
78d597f27a85e5d69246ce15656dd0568c927257]
[ 39.732051] kernel: nfnetlink_rcv_batch+0x8c3/0xb80 [nfnetlink
938a1b64e36f407a05edbdcd1906670ecd99bb43]
[ 39.732076] kernel: nfnetlink_rcv+0x195/0x1c0 [nfnetlink
938a1b64e36f407a05edbdcd1906670ecd99bb43]
[ 39.732101] kernel: netlink_unicast+0x288/0x3c0
[ 39.732126] kernel: netlink_sendmsg+0x20d/0x430
[ 39.732138] kernel: ____sys_sendmsg+0x388/0x3c0
[ 39.732149] kernel: ? import_iovec+0x1b/0x30
[ 39.732160] kernel: ___sys_sendmsg+0x99/0xe0
[ 39.732172] kernel: __sys_sendmsg+0x8a/0xf0
[ 39.732184] kernel: do_syscall_64+0x81/0x610
[ 39.732202] kernel: ? __handle_mm_fault+0xb46/0xf60
[ 39.732228] kernel: ? perf_event_task_tick+0x4f/0xb0
[ 39.732256] kernel: ? count_memcg_events+0xc2/0x170
[ 39.732279] kernel: ? handle_mm_fault+0x1d7/0x2d0
[ 39.732306] kernel: ? do_user_addr_fault+0x21a/0x690
[ 39.732333] kernel: ? exc_page_fault+0x7e/0x1a0
[ 39.732358] kernel: entry_SYSCALL_64_after_hwframe+0x76/0x7e


(gdb) list *(nf_tables_abort_release+0x22f/0x260)
0x10c20 is in nf_tables_abort_release
(net/netfilter/nf_tables_api.c:11119).
11114 mutex_lock(&nft_net->commit_mutex);
11115 list_splice(&module_list, &nft_net->module_list);
11116 }
11117
11118 static void nf_tables_abort_release(struct nft_trans *trans)
11119 {
11120 struct nft_ctx ctx = { };
11121
11122 nft_ctx_update(&ctx, trans);


After this there are a lot of repeated lines like
[ 39.732596] kernel: page: refcount:0 mapcount:0
mapping:0000000000000000 index:0xffff89c66b61a140 pfn:0x12b61a
[ 39.733541] kernel: raw: ffff89c66b620180 0000000000400000
00000000ffffffff 0000000000000000
[ 39.733738] kernel: raw: ffff89c66b61fc80 0000000000400000
00000000ffffffff 0000000000000000
[ 39.733874] kernel: raw: ffff89c66b61fc80 0000000000400000
00000000ffffffff 0000000000000000
[ 39.734032] kernel: raw: ffff89c66b61ea40 0000000000400000
00000000ffffffff 0000000000000000
[ 39.749164] kernel: flags:
0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)
[ 39.749221] kernel: raw: 0017ffffc0000000 fffffa5a04ad8d88
fffffa5a04ad8d48 0000000000000000
[ 39.749243] kernel: raw: ffff89c66b634880 0000000000400000
00000000ffffffff 0000000000000000
[ 39.749266] kernel: page dumped because: Not a kmalloc allocation
[ 39.749283] kernel: page: refcount:0 mapcount:0
mapping:0000000000000000 index:0xffff89c66b634880 pfn:0x12b634
[ 39.749306] kernel: flags:
0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)
[ 39.749329] kernel: raw: 0017ffffc0000000 fffffa5a04ad8d88
fffffa5a04ad8d48 0000000000000000
[ 39.749351] kernel: raw: ffff89c66b634880 0000000000400000
00000000ffffffff 0000000000000000
[ 39.749372] kernel: page dumped because: Not a kmalloc allocation
...

--
Gene

Attachment: klog-6.19.3
Description: Unix manual page

Attachment: klog-6.19.4
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