[syzbot] [btrfs?] WARNING in btrfs_add_delayed_iput (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 6fab32bb6508 MAINTAINERS: add Mark Brown as a linux-next m..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17a68be2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=cb8e856ee40b632b
dashboard link: https://syzkaller.appspot.com/bug?extid=e0babece4b4300d51e73
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4d337be0cf04/disk-6fab32bb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f56ca33e777c/vmlinux-6fab32bb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d7a51e41c32b/bzImage-6fab32bb.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e0babe...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 13187 at fs/btrfs/inode.c:3450 btrfs_add_delayed_iput+0x2e6/0x360 fs/btrfs/inode.c:3450
Modules linked in:
CPU: 1 UID: 0 PID: 13187 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:btrfs_add_delayed_iput+0x2e6/0x360 fs/btrfs/inode.c:3450
Code: b0 8b 5c fe 48 8b 3b 48 83 c4 20 5b 41 5c 41 5d 41 5e 41 5f 5d e9 aa ea cb fd e8 f5 d3 fa fd e9 f5 fd ff ff e8 eb d3 fa fd 90 <0f> 0b 90 e9 4f fe ff ff 44 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 81
RSP: 0000:ffffc90004c5f400 EFLAGS: 00010246
RAX: ffffffff83c3e995 RBX: ffff8880231b8000 RCX: ffff88802c349e00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000100
R10: dffffc0000000000 R11: ffffed1004637471 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff888066d7b3b8 R15: 0000000000000200
FS: 0000555559d1c500(0000) GS:ffff888126efc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdffda00000 CR3: 000000006b4be000 CR4: 00000000003526f0
Call Trace:
<TASK>
btrfs_put_ordered_extent+0x19f/0x470 fs/btrfs/ordered-data.c:635
blk_update_request+0x57e/0xe60 block/blk-mq.c:998
blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1160
blk_complete_reqs block/blk-mq.c:1235 [inline]
blk_done_softirq+0x10a/0x160 block/blk-mq.c:1240
handle_softirqs+0x22f/0x710 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
__local_bh_enable_ip+0x1a0/0x2e0 kernel/softirq.c:302
lock_sock include/net/sock.h:1679 [inline]
netlink_insert+0xd3/0x1370 net/netlink/af_netlink.c:557
__netlink_kernel_create+0x2b0/0x710 net/netlink/af_netlink.c:2038
netlink_kernel_create include/linux/netlink.h:62 [inline]
rdma_nl_net_init+0xcc/0x180 drivers/infiniband/core/netlink.c:318
rdma_dev_init_net+0x95/0x270 drivers/infiniband/core/device.c:1201
ops_init+0x35c/0x5c0 net/core/net_namespace.c:137
setup_net+0xfe/0x320 net/core/net_namespace.c:445
copy_net_ns+0x34e/0x4e0 net/core/net_namespace.c:580
create_new_namespaces+0x3f3/0x720 kernel/nsproxy.c:110
unshare_nsproxy_namespaces+0x11c/0x170 kernel/nsproxy.c:218
ksys_unshare+0x4c8/0x8c0 kernel/fork.c:3129
__do_sys_unshare kernel/fork.c:3200 [inline]
__se_sys_unshare kernel/fork.c:3198 [inline]
__x64_sys_unshare+0x38/0x50 kernel/fork.c:3198
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1ba19707c7
Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 10 01 00 00 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:00007fff95a532e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f1ba1bc5f40 RCX: 00007f1ba19707c7
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 00007f1ba1bc67b8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000008
R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000
</TASK>


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