[v6.6] WARNING in page_pool_put_defragged_page

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: dbcb8d8e4163 Linux 6.6.100
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16d138a2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=293251cfa8d8100
dashboard link: https://syzkaller.appspot.com/bug?extid=debd4d337dae4476ebb3
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d0b56817a2c3/disk-dbcb8d8e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f0d646b2f7fa/vmlinux-dbcb8d8e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1e0b752a5011/bzImage-dbcb8d8e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+debd4d...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 6586 at net/core/page_pool.c:594 __page_pool_put_page net/core/page_pool.c:594 [inline]
WARNING: CPU: 0 PID: 6586 at net/core/page_pool.c:594 page_pool_put_defragged_page+0x9a/0x9b0 net/core/page_pool.c:641
Modules linked in:
CPU: 0 PID: 6586 Comm: syz.0.252 Not tainted 6.6.100-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__page_pool_put_page net/core/page_pool.c:594 [inline]
RIP: 0010:page_pool_put_defragged_page+0x9a/0x9b0 net/core/page_pool.c:641
Code: e8 eb 20 0b f9 eb 47 e8 e4 20 0b f9 eb 40 65 44 8b 25 16 12 88 77 31 ff 44 89 e6 e8 80 24 0b f9 45 85 e4 74 09 e8 c6 20 0b f9 <0f> 0b eb 20 65 44 8b 25 f2 11 88 77 31 ff 44 89 e6 e8 60 24 0b f9
RSP: 0018:ffffc9001a04e8f0 EFLAGS: 00010083
RAX: ffffffff887a7b1f RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc9000de4e000 RSI: 0000000000001ba3 RDI: 0000000000001ba4
RBP: dffffc0000000000 R08: ffff88802b20bc00 R09: 0000000000000004
R10: 0000000000000003 R11: 0000000000000002 R12: 0000000000000000
R13: ffffea0000944d80 R14: ffff88801b730000 R15: 00000000ffffffff
FS: 00007fc03eea66c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2de06ff8 CR3: 0000000022773000 CR4: 00000000003506f0
Call Trace:
<TASK>
tun_ptr_free drivers/net/tun.c:617 [inline]
__ptr_ring_swap_queue include/linux/ptr_ring.h:570 [inline]
ptr_ring_resize_multiple include/linux/ptr_ring.h:641 [inline]
tun_queue_resize drivers/net/tun.c:3685 [inline]
tun_device_event+0xa66/0x1030 drivers/net/tun.c:3705
notifier_call_chain+0x197/0x390 kernel/notifier.c:93
call_netdevice_notifiers_extack net/core/dev.c:2064 [inline]
call_netdevice_notifiers net/core/dev.c:2078 [inline]
dev_change_tx_queue_len+0x121/0x260 net/core/dev.c:8859
do_setlink+0xf93/0x3fb0 net/core/rtnetlink.c:2928
rtnl_setlink+0x399/0x4b0 net/core/rtnetlink.c:3208
rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6475
netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2555
netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1356
netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1904
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x5bf/0x950 net/socket.c:2595
___sys_sendmsg+0x220/0x290 net/socket.c:2649
__sys_sendmsg net/socket.c:2678 [inline]
__do_sys_sendmsg net/socket.c:2687 [inline]
__se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc03df8e9a9
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:00007fc03eea6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fc03e1b6080 RCX: 00007fc03df8e9a9
RDX: 0000000000000000 RSI: 0000200000000140 RDI: 000000000000000d
RBP: 00007fc03e010d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fc03e1b6080 R15: 00007ffea86c88c8
</TASK>


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: dbcb8d8e4163 Linux 6.6.100
git tree: linux-6.6.y

console output: https://syzkaller.appspot.com/x/log.txt?x=15816034580000

kernel config: https://syzkaller.appspot.com/x/.config?x=293251cfa8d8100
dashboard link: https://syzkaller.appspot.com/bug?extid=debd4d337dae4476ebb3
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13816034580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1755a782580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d0b56817a2c3/disk-dbcb8d8e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f0d646b2f7fa/vmlinux-dbcb8d8e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1e0b752a5011/bzImage-dbcb8d8e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+debd4d...@syzkaller.appspotmail.com

------------[ cut here ]------------

WARNING: CPU: 1 PID: 5943 at net/core/page_pool.c:594 __page_pool_put_page net/core/page_pool.c:594 [inline]
WARNING: CPU: 1 PID: 5943 at net/core/page_pool.c:594 page_pool_put_defragged_page+0x9a/0x9b0 net/core/page_pool.c:641
Modules linked in:
CPU: 1 PID: 5943 Comm: syz.0.16 Not tainted 6.6.100-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__page_pool_put_page net/core/page_pool.c:594 [inline]
RIP: 0010:page_pool_put_defragged_page+0x9a/0x9b0 net/core/page_pool.c:641
Code: e8 eb 20 0b f9 eb 47 e8 e4 20 0b f9 eb 40 65 44 8b 25 16 12 88 77 31 ff 44 89 e6 e8 80 24 0b f9 45 85 e4 74 09 e8 c6 20 0b f9 <0f> 0b eb 20 65 44 8b 25 f2 11 88 77 31 ff 44 89 e6 e8 60 24 0b f9

RSP: 0018:ffffc900030468f0 EFLAGS: 00010093
RAX: ffffffff887a7b1f RBX: 0000000000000000 RCX: ffff888018ea9e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffff888018ea9e00 R09: 0000000000000004
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000
R13: ffffea0001de5b00 R14: ffff88801c781000 R15: 00000000ffffffff
FS: 000055555d794500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000

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

CR2: 00007ffdb4df1d58 CR3: 0000000077980000 CR4: 00000000003506e0

RIP: 0033:0x7f4e7cd8e9a9

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:00007ffdb55f3c48 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f4e7cfb5fa0 RCX: 00007f4e7cd8e9a9
RDX: 0000000000000000 RSI: 0000200000000140 RDI: 000000000000000c
RBP: 00007f4e7ce10d69 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007f4e7cfb5fa0 R14: 00007f4e7cfb5fa0 R15: 0000000000000003
</TASK>


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