[syzbot] [net?] WARNING in cleanup_net (4)

syzbot
2025-02-20T13:15:24Z

Hello,

syzbot found the following issue on:

HEAD commit: 6537cfb395f3 Merge tag 'sound-6.14-rc4' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16a327f8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=61cbf5ac8a063ad4
dashboard link: https://syzkaller.appspot.com/bug?extid=30a19e01a97420719891
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10bf9ae4580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13d89498580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ae2568ec9e34/disk-6537cfb3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/19be7179f649/vmlinux-6537cfb3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bd8a168d2027/bzImage-6537cfb3.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+30a19e01a97420719891@syzkaller.appspotmail.com

proc_sctp_do_udp_port+0x380/0x450 net/sctp/sysctl.c:555
proc_sys_call_handler+0x3c6/0x5a0 fs/proc/proc_sysctl.c:601
iter_file_splice_write+0x90f/0x10b0 fs/splice.c:743
do_splice_from fs/splice.c:941 [inline]
direct_splice_actor+0x18f/0x6c0 fs/splice.c:1164
splice_direct_to_actor+0x346/0xa40 fs/splice.c:1108
do_splice_direct_actor fs/splice.c:1207 [inline]
do_splice_direct+0x178/0x250 fs/splice.c:1233
do_sendfile+0xafb/0xe40 fs/read_write.c:1363
__do_sys_sendfile64 fs/read_write.c:1424 [inline]
__se_sys_sendfile64 fs/read_write.c:1410 [inline]
__x64_sys_sendfile64+0x1da/0x220 fs/read_write.c:1410
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
------------[ cut here ]------------
WARNING: CPU: 0 PID: 12 at lib/ref_tracker.c:179 ref_tracker_dir_exit+0x3e3/0x680 lib/ref_tracker.c:179
Modules linked in:
CPU: 0 UID: 0 PID: 12 Comm: kworker/u8:1 Not tainted 6.14.0-rc3-syzkaller-00060-g6537cfb395f3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: netns cleanup_net
RIP: 0010:ref_tracker_dir_exit+0x3e3/0x680 lib/ref_tracker.c:179
Code: 11 02 00 00 4d 39 f5 49 8b 06 4d 89 f7 0f 85 0e ff ff ff 48 8b 2c 24 e8 5b 16 c8 fc 48 8b 74 24 18 48 89 ef e8 6e bd 65 06 90 <0f> 0b 90 e8 45 16 c8 fc 48 8d 5d 44 be 04 00 00 00 48 89 df e8 c4
RSP: 0018:ffffc90000117ac8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff8b6ceca0 RDI: 0000000000000001
RBP: ffff88802f7b01e0 R08: 0000000000000001 R09: fffffbfff2dd79b7
R10: ffffffff96ebcdbf R11: 0000000000002ba2 R12: ffff88802f7b0230
R13: ffff88802f7b0230 R14: ffff88802f7b0230 R15: ffff88802f7b0230
FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557010814f20 CR3: 000000000df80000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
net_free net/core/net_namespace.c:473 [inline]
net_free net/core/net_namespace.c:467 [inline]
cleanup_net+0x99f/0xbf0 net/core/net_namespace.c:675
process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236
process_scheduled_works kernel/workqueue.c:3317 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
kthread+0x3af/0x750 kernel/kthread.c:464
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

---
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