[v6.1] WARNING in bpf_xdp_link_release

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1989cd3d56e2 Linux 6.1.167
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10786302580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0605c5af04d7603
dashboard link: https://syzkaller.appspot.com/bug?extid=b174e5c4f1c37769bac7
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/814271465bd5/disk-1989cd3d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bd559379c491/vmlinux-1989cd3d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/063c12bf8ba7/bzImage-1989cd3d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b174e5...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 5535 at net/core/dev.c:9418 dev_xdp_detach_link net/core/dev.c:9418 [inline]
WARNING: CPU: 1 PID: 5535 at net/core/dev.c:9418 bpf_xdp_link_release+0x468/0x4c0 net/core/dev.c:9433
Modules linked in:
CPU: 1 PID: 5535 Comm: syz.4.270 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:dev_xdp_detach_link net/core/dev.c:9418 [inline]
RIP: 0010:bpf_xdp_link_release+0x468/0x4c0 net/core/dev.c:9433
Code: 00 00 00 65 48 8b 04 25 28 00 00 00 48 3b 84 24 80 00 00 00 75 46 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 48 1c 4e f9 <0f> 0b e9 68 ff ff ff e8 3c 1c 4e f9 c6 05 bb 1f d7 05 01 48 c7 c7
RSP: 0018:ffffc90003af7c40 EFLAGS: 00010293
RAX: ffffffff88345848 RBX: 1ffff9200075ef8c RCX: ffff88807f3b3b80
RDX: 0000000000000000 RSI: 00000000ffffffa1 RDI: 0000000000000000
RBP: ffffc90003af7d10 R08: ffff88807f3b3b80 R09: 0000000000000004
R10: 0000000000000004 R11: 0000000000000000 R12: ffff888058f7cbf8
R13: 00000000ffffffa1 R14: ffffc90003af7c80 R15: 0000000000000000
FS: 000055557c4f4500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f05c7b4da08 CR3: 0000000059110000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
bpf_link_free kernel/bpf/syscall.c:2769 [inline]
bpf_link_put+0x22a/0x2c0 kernel/bpf/syscall.c:2795
bpf_link_release+0x37/0x40 kernel/bpf/syscall.c:2804
__fput+0x22c/0x920 fs/file_table.c:320
task_work_run+0x1d0/0x260 kernel/task_work.c:203
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fdd3c99c819
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:00007ffead2bd458 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fdd3cc17da0 RCX: 00007fdd3c99c819
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fdd3cc17da0 R08: 00007fdd3cc16218 R09: 0000000000000000
R10: 00000000003ffd08 R11: 0000000000000246 R12: 000000000002b382
R13: 00007fdd3cc1618c R14: 000000000002b116 R15: 00007ffead2bd560
</TASK>


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 1989cd3d56e2 Linux 6.1.167
git tree: linux-6.1.y

console output: https://syzkaller.appspot.com/x/log.txt?x=15f26dca580000

kernel config: https://syzkaller.appspot.com/x/.config?x=f0605c5af04d7603
dashboard link: https://syzkaller.appspot.com/bug?extid=b174e5c4f1c37769bac7
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1761b8f2580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13012e06580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/814271465bd5/disk-1989cd3d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bd559379c491/vmlinux-1989cd3d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/063c12bf8ba7/bzImage-1989cd3d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b174e5...@syzkaller.appspotmail.com

device bond1 entered promiscuous mode
------------[ cut here ]------------
WARNING: CPU: 1 PID: 4478 at net/core/dev.c:9418 dev_xdp_detach_link net/core/dev.c:9418 [inline]
WARNING: CPU: 1 PID: 4478 at net/core/dev.c:9418 bpf_xdp_link_release+0x468/0x4c0 net/core/dev.c:9433
Modules linked in:
CPU: 1 PID: 4478 Comm: syz.0.87 Not tainted syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:dev_xdp_detach_link net/core/dev.c:9418 [inline]
RIP: 0010:bpf_xdp_link_release+0x468/0x4c0 net/core/dev.c:9433
Code: 00 00 00 65 48 8b 04 25 28 00 00 00 48 3b 84 24 80 00 00 00 75 46 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 48 1c 4e f9 <0f> 0b e9 68 ff ff ff e8 3c 1c 4e f9 c6 05 bb 1f d7 05 01 48 c7 c7

RSP: 0018:ffffc9000384fc40 EFLAGS: 00010293
RAX: ffffffff88345848 RBX: 1ffff92000709f8c RCX: ffff88802aa38000

RDX: 0000000000000000 RSI: 00000000ffffffa1 RDI: 0000000000000000

RBP: ffffc9000384fd10 R08: ffff88802aa38000 R09: 0000000000000004
R10: 0000000000000004 R11: 0000000000000000 R12: ffff88802d828bf8
R13: 00000000ffffffa1 R14: ffffc9000384fc80 R15: 0000000000000000
FS: 0000555567a62500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000000000000000 CR3: 000000001c66d000 CR4: 00000000003506e0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
bpf_link_free kernel/bpf/syscall.c:2769 [inline]
bpf_link_put+0x22a/0x2c0 kernel/bpf/syscall.c:2795
bpf_link_release+0x37/0x40 kernel/bpf/syscall.c:2804
__fput+0x22c/0x920 fs/file_table.c:320
task_work_run+0x1d0/0x260 kernel/task_work.c:203
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2

RIP: 0033:0x7f72a3b9c819

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:00007ffcf860ae98 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffcf860af80 RCX: 00007f72a3b9c819

RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003

RBP: 0000000000015614 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2d020000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f72a3e15fac R14: 00007f72a3e15fa8 R15: 00007f72a3e15fa0
</TASK>


---
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