linux-kernel - [syzbot] [cgroups?] WARNING in css_rstat

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Message-ID: <684c5802.a00a0220.279073.0016.GAE@google.com>
Date: Fri, 13 Jun 2025 09:55:30 -0700
From: syzbot <syzbot+8d052e8b99e40bc625ed@...kaller.appspotmail.com>
To: cgroups@...r.kernel.org, hannes@...xchg.org, linux-kernel@...r.kernel.org, 
	mkoutny@...e.com, syzkaller-bugs@...glegroups.com, tj@...nel.org
Subject: [syzbot] [cgroups?] WARNING in css_rstat_exit

Hello,

syzbot found the following issue on:

HEAD commit:    27605c8c0f69 Merge tag 'net-6.16-rc2' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=103b1e0c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=89df02a4e09cb64d
dashboard link: https://syzkaller.appspot.com/bug?extid=8d052e8b99e40bc625ed
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/79ab1e186123/disk-27605c8c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d37bf85b966d/vmlinux-27605c8c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/eed2865abf8f/bzImage-27605c8c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8d052e8b99e40bc625ed@...kaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 5887 at kernel/cgroup/rstat.c:497 css_rstat_exit+0x368/0x470 kernel/cgroup/rstat.c:497
Modules linked in:
CPU: 0 UID: 0 PID: 5887 Comm: kworker/0:5 Not tainted 6.16.0-rc1-syzkaller-00101-g27605c8c0f69 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: cgroup_destroy css_free_rwork_fn
RIP: 0010:css_rstat_exit+0x368/0x470 kernel/cgroup/rstat.c:497
Code: 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 0e 01 00 00 49 c7 85 70 05 00 00 00 00 00 00 e9 00 ff ff ff e8 c9 07 07 00 90 <0f> 0b 90 e9 3e ff ff ff e8 bb 07 07 00 90 0f 0b 90 e9 30 ff ff ff
RSP: 0000:ffffc9000b6afbc0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff888057c7a800 RCX: ffff888124754000
RDX: ffff8880308b8000 RSI: ffffffff81b514e7 RDI: ffffffff8df26da0
RBP: ffff888057c7a808 R08: 0000000000000005 R09: 0000000000000007
R10: 0000000000000000 R11: 0000000000000001 R12: ffff888057c7a820
R13: 0000000000000000 R14: 0000000000000003 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888124754000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31b10ff8 CR3: 0000000079092000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 css_free_rwork_fn+0x80/0x12e0 kernel/cgroup/cgroup.c:5449
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


---
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