linux-kernel - [syzbot] [cgroups?] BUG: unable to handle kernel paging request in css_rstat

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Message-ID: <68403875.a00a0220.d4325.000a.GAE@google.com>
Date: Wed, 04 Jun 2025 05:13:41 -0700
From: syzbot <syzbot+36ca05bdc071f7ba8f75@...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?] BUG: unable to handle kernel paging request in css_rstat_flush

Hello,

syzbot found the following issue on:

HEAD commit:    4cb6c8af8591 selftests/filesystems: Fix build of anon_inod..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17967ed4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=43b7075a5c42ffca
dashboard link: https://syzkaller.appspot.com/bug?extid=36ca05bdc071f7ba8f75
compiler:       Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=170d9970580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13e88c82580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-4cb6c8af.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/91b28032d866/vmlinux-4cb6c8af.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7cf2a9f8c096/bzImage-4cb6c8af.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+36ca05bdc071f7ba8f75@...kaller.appspotmail.com

BUG: unable to handle page fault for address: ffffed1011a4ca01
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 5ffcd067 P4D 5ffcd067 PUD 2fff7067 PMD 0 
Oops: Oops: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5328 Comm: kworker/0:3 Not tainted 6.15.0-syzkaller-10402-g4cb6c8af8591 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: cgroup_destroy css_free_rwork_fn
RIP: 0010:css_rstat_updated_list kernel/cgroup/rstat.c:284 [inline]
RIP: 0010:css_rstat_flush+0x5ff/0x1fa0 kernel/cgroup/rstat.c:413
Code: 1e 75 d1 0d 01 0f 85 e6 14 00 00 e8 1b 1e 07 00 4c 03 6c 24 20 4d 8d 7d 08 4c 89 fb 48 c1 eb 03 48 b8 00 00 00 00 00 fc ff df <80> 3c 03 00 74 08 4c 89 ff e8 e3 51 6a 00 49 83 3f 00 0f 84 5d 01
RSP: 0018:ffffc9000d68f780 EFLAGS: 00010802
RAX: dffffc0000000000 RBX: 1ffff11011a4ca01 RCX: ffff88801f4ea440
RDX: 0000000000000000 RSI: ffffffff8be266a0 RDI: ffffffff8be26660
RBP: ffffc9000d68f9b8 R08: ffffffff8fa0aaf7 R09: 1ffffffff1f4155e
R10: dffffc0000000000 R11: fffffbfff1f4155f R12: ffff88801fc42590
R13: ffff88808d265000 R14: 0000000000000000 R15: ffff88808d265008
FS:  0000000000000000(0000) GS:ffff88808d265000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffed1011a4ca01 CR3: 0000000042fe0000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 css_rstat_exit+0xa9/0x320 kernel/cgroup/rstat.c:479
 css_free_rwork_fn+0x8b/0xc50 kernel/cgroup/cgroup.c:5449
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
CR2: ffffed1011a4ca01
---[ end trace 0000000000000000 ]---
RIP: 0010:css_rstat_updated_list kernel/cgroup/rstat.c:284 [inline]
RIP: 0010:css_rstat_flush+0x5ff/0x1fa0 kernel/cgroup/rstat.c:413
Code: 1e 75 d1 0d 01 0f 85 e6 14 00 00 e8 1b 1e 07 00 4c 03 6c 24 20 4d 8d 7d 08 4c 89 fb 48 c1 eb 03 48 b8 00 00 00 00 00 fc ff df <80> 3c 03 00 74 08 4c 89 ff e8 e3 51 6a 00 49 83 3f 00 0f 84 5d 01
RSP: 0018:ffffc9000d68f780 EFLAGS: 00010802
RAX: dffffc0000000000 RBX: 1ffff11011a4ca01 RCX: ffff88801f4ea440
RDX: 0000000000000000 RSI: ffffffff8be266a0 RDI: ffffffff8be26660
RBP: ffffc9000d68f9b8 R08: ffffffff8fa0aaf7 R09: 1ffffffff1f4155e
R10: dffffc0000000000 R11: fffffbfff1f4155f R12: ffff88801fc42590
R13: ffff88808d265000 R14: 0000000000000000 R15: ffff88808d265008
FS:  0000000000000000(0000) GS:ffff88808d265000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffed1011a4ca01 CR3: 0000000042fe0000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 5 bytes skipped:
   0:	0f 85 e6 14 00 00    	jne    0x14ec
   6:	e8 1b 1e 07 00       	call   0x71e26
   b:	4c 03 6c 24 20       	add    0x20(%rsp),%r13
  10:	4d 8d 7d 08          	lea    0x8(%r13),%r15
  14:	4c 89 fb             	mov    %r15,%rbx
  17:	48 c1 eb 03          	shr    $0x3,%rbx
  1b:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  22:	fc ff df
* 25:	80 3c 03 00          	cmpb   $0x0,(%rbx,%rax,1) <-- trapping instruction
  29:	74 08                	je     0x33
  2b:	4c 89 ff             	mov    %r15,%rdi
  2e:	e8 e3 51 6a 00       	call   0x6a5216
  33:	49 83 3f 00          	cmpq   $0x0,(%r15)
  37:	0f                   	.byte 0xf
  38:	84 5d 01             	test   %bl,0x1(%rbp)


---
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