Message-ID: <68c3c675.050a0220.2ff435.0353.GAE@google.com>
Date: Fri, 12 Sep 2025 00:06:29 -0700
From: syzbot <syzbot+5a66db916cdde0dbcc1c@...kaller.appspotmail.com>
To: davem@...emloft.net, edumazet@...gle.com, horms@...nel.org, 
	kuba@...nel.org, linux-kernel@...r.kernel.org, netdev@...r.kernel.org, 
	pabeni@...hat.com, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [net?] BUG: corrupted list in flow_block_cb_setup_simple

Hello,

syzbot found the following issue on:

HEAD commit:    e59a039119c3 Merge tag 's390-6.17-4' of git://git.kernel.o..
git tree:       bpf
console output: https://syzkaller.appspot.com/x/log.txt?x=1523e934580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4d8792ecb6308d0f
dashboard link: https://syzkaller.appspot.com/bug?extid=5a66db916cdde0dbcc1c
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16d4bd62580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10d69642580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/324da524bbd8/disk-e59a0391.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0fa38e1d54f4/vmlinux-e59a0391.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b1ea8074daa0/bzImage-e59a0391.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5a66db916cdde0dbcc1c@...kaller.appspotmail.com

 non-slab/vmalloc memory
list_del corruption. prev->next should be ffff888077fdb100, but was ffffffff8edac9a0. (prev=ffffffff8edac9a0)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:64!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6449 Comm: syz.3.301 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 4b a5 31 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 1c 9d 52 fd 49 8b 17 48 c7 c7 a0 40 e3 8b 48 89 de 4c 89 f9 e8 07 0b 57 fc 90 <0f> 0b 4c 89 f7 e8 1c a5 31 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 ed
RSP: 0018:ffffc90003f4e760 EFLAGS: 00010246
RAX: 000000000000006d RBX: ffff888077fdb100 RCX: 21dc4908dd936700
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffff920007e9d3e R08: ffffc90003f4e487 R09: 1ffff920007e9c90
R10: dffffc0000000000 R11: fffff520007e9c91 R12: 1ffffffff1db5934
R13: dffffc0000000000 R14: ffffffff8edac9a0 R15: ffffffff8edac9a0
FS:  00005555769e1500(0000) GS:ffff888125c15000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000380 CR3: 0000000030806000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __list_del_entry_valid include/linux/list.h:124 [inline]
 __list_del_entry include/linux/list.h:215 [inline]
 list_del include/linux/list.h:229 [inline]
 flow_block_cb_setup_simple+0x62d/0x740 net/core/flow_offload.c:369
 nft_block_offload_cmd net/netfilter/nf_tables_offload.c:397 [inline]
 nft_chain_offload_cmd+0x290/0x660 net/netfilter/nf_tables_offload.c:451
 nft_flow_block_chain net/netfilter/nf_tables_offload.c:471 [inline]
 nft_flow_offload_chain net/netfilter/nf_tables_offload.c:513 [inline]
 nft_flow_rule_offload_commit+0x40d/0x1b60 net/netfilter/nf_tables_offload.c:592
 nf_tables_commit+0x675/0x8700 net/netfilter/nf_tables_api.c:10933
 nfnetlink_rcv_batch net/netfilter/nfnetlink.c:574 [inline]
 nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:647 [inline]
 nfnetlink_rcv+0x1a4e/0x2520 net/netfilter/nfnetlink.c:665
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:729
 ____sys_sendmsg+0x505/0x830 net/socket.c:2614
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668
 __sys_sendmsg net/socket.c:2700 [inline]
 __do_sys_sendmsg net/socket.c:2705 [inline]
 __se_sys_sendmsg net/socket.c:2703 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2703
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe1b0d8eba9
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:00007ffc23fb3798 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe1b0fd5fa0 RCX: 00007fe1b0d8eba9
RDX: 000000000000c050 RSI: 0000200000000cc0 RDI: 0000000000000003
RBP: 00007fe1b0e11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe1b0fd5fa0 R14: 00007fe1b0fd5fa0 R15: 0000000000000003
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 4b a5 31 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 1c 9d 52 fd 49 8b 17 48 c7 c7 a0 40 e3 8b 48 89 de 4c 89 f9 e8 07 0b 57 fc 90 <0f> 0b 4c 89 f7 e8 1c a5 31 fd 43 80 3c 2c 00 74 08 4c 89 ff e8 ed
RSP: 0018:ffffc90003f4e760 EFLAGS: 00010246
RAX: 000000000000006d RBX: ffff888077fdb100 RCX: 21dc4908dd936700
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffff920007e9d3e R08: ffffc90003f4e487 R09: 1ffff920007e9c90
R10: dffffc0000000000 R11: fffff520007e9c91 R12: 1ffffffff1db5934
R13: dffffc0000000000 R14: ffffffff8edac9a0 R15: ffffffff8edac9a0
FS:  00005555769e1500(0000) GS:ffff888125c15000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000380 CR3: 0000000030806000 CR4: 00000000003526f0


---
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