linux-kernel - [syzbot] [cgroups?] general protection fault in cgroup_rstat

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <681e51ba.050a0220.a19a9.013a.GAE@google.com>
Date: Fri, 09 May 2025 12:04:26 -0700
From: syzbot <syzbot+175b931e69c9ad9e1945@...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?] general protection fault in cgroup_rstat_flush

Hello,

syzbot found the following issue on:

HEAD commit:    9c69f8884904 Merge tag 'bcachefs-2025-05-08' of git://evil..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1440acf4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b9683d529ec1b880
dashboard link: https://syzkaller.appspot.com/bug?extid=175b931e69c9ad9e1945
compiler:       Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/062b75278fb3/disk-9c69f888.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/868b31a2cf71/vmlinux-9c69f888.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e773657fdf9c/bzImage-9c69f888.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+175b931e69c9ad9e1945@...kaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xe7ffed1c349f36f7: 0000 [#1] SMP KASAN PTI
KASAN: maybe wild-memory-access in range [0x3fff88e1a4f9b7b8-0x3fff88e1a4f9b7bf]
CPU: 0 UID: 0 PID: 52 Comm: kworker/u8:3 Not tainted 6.15.0-rc5-syzkaller-00136-g9c69f8884904 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: events_unbound flush_memcg_stats_dwork
RIP: 0010:cgroup_rstat_push_children kernel/cgroup/rstat.c:165 [inline]
RIP: 0010:cgroup_rstat_updated_list kernel/cgroup/rstat.c:245 [inline]
RIP: 0010:cgroup_rstat_flush+0x840/0x1e70 kernel/cgroup/rstat.c:325
Code: 70 74 08 48 89 df e8 ef e6 66 00 4c 8b 23 4b 8d 1c 3c 48 81 c3 a0 00 00 00 49 89 dd 49 c1 ed 03 48 b8 00 00 00 00 00 fc ff df <41> 80 7c 05 00 00 74 08 48 89 df e8 c0 e6 66 00 48 8b 03 48 3b 44
RSP: 0018:ffffc90000bd7920 EFLAGS: 00010003
RAX: dffffc0000000000 RBX: 3fff88e1a4f9b7bd RCX: 1ffffffff1b2b383
RDX: 0000000000000000 RSI: ffffffff8bc0fec0 RDI: ffff88806481c5c1
RBP: ffffc90000bd7b08 R08: ffffffff8f7da777 R09: 1ffffffff1efb4ee
R10: dffffc0000000000 R11: fffffbfff1efb4ef R12: ffff888126200000
R13: 07fff11c349f36f7 R14: 0000000000000000 R15: 400000607ed9b71d
FS:  0000000000000000(0000) GS:ffff888126100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005598d2923440 CR3: 000000005d74e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 flush_memcg_stats_dwork+0x15/0x60 mm/memcontrol.c:653
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:cgroup_rstat_push_children kernel/cgroup/rstat.c:165 [inline]
RIP: 0010:cgroup_rstat_updated_list kernel/cgroup/rstat.c:245 [inline]
RIP: 0010:cgroup_rstat_flush+0x840/0x1e70 kernel/cgroup/rstat.c:325
Code: 70 74 08 48 89 df e8 ef e6 66 00 4c 8b 23 4b 8d 1c 3c 48 81 c3 a0 00 00 00 49 89 dd 49 c1 ed 03 48 b8 00 00 00 00 00 fc ff df <41> 80 7c 05 00 00 74 08 48 89 df e8 c0 e6 66 00 48 8b 03 48 3b 44
RSP: 0018:ffffc90000bd7920 EFLAGS: 00010003
RAX: dffffc0000000000 RBX: 3fff88e1a4f9b7bd RCX: 1ffffffff1b2b383
RDX: 0000000000000000 RSI: ffffffff8bc0fec0 RDI: ffff88806481c5c1
RBP: ffffc90000bd7b08 R08: ffffffff8f7da777 R09: 1ffffffff1efb4ee
R10: dffffc0000000000 R11: fffffbfff1efb4ef R12: ffff888126200000
R13: 07fff11c349f36f7 R14: 0000000000000000 R15: 400000607ed9b71d
FS:  0000000000000000(0000) GS:ffff888126100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005598d2923440 CR3: 000000005d74e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	70 74                	jo     0x76
   2:	08 48 89             	or     %cl,-0x77(%rax)
   5:	df e8                	fucomip %st(0),%st
   7:	ef                   	out    %eax,(%dx)
   8:	e6 66                	out    %al,$0x66
   a:	00 4c 8b 23          	add    %cl,0x23(%rbx,%rcx,4)
   e:	4b 8d 1c 3c          	lea    (%r12,%r15,1),%rbx
  12:	48 81 c3 a0 00 00 00 	add    $0xa0,%rbx
  19:	49 89 dd             	mov    %rbx,%r13
  1c:	49 c1 ed 03          	shr    $0x3,%r13
  20:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  27:	fc ff df
* 2a:	41 80 7c 05 00 00    	cmpb   $0x0,0x0(%r13,%rax,1) <-- trapping instruction
  30:	74 08                	je     0x3a
  32:	48 89 df             	mov    %rbx,%rdi
  35:	e8 c0 e6 66 00       	call   0x66e6fa
  3a:	48 8b 03             	mov    (%rbx),%rax
  3d:	48                   	rex.W
  3e:	3b                   	.byte 0x3b
  3f:	44                   	rex.R


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@...glegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup