linux-kernel - [syzbot] [cgroups?] [mm?] WARNING in memcg1

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Message-ID: <696b56b1.050a0220.3390f1.0007.GAE@google.com>
Date: Sat, 17 Jan 2026 01:30:25 -0800
From: syzbot <syzbot+079a3b213add54dd18a7@...kaller.appspotmail.com>
To: akpm@...ux-foundation.org, cgroups@...r.kernel.org, hannes@...xchg.org, 
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, mhocko@...nel.org, 
	muchun.song@...ux.dev, roman.gushchin@...ux.dev, shakeel.butt@...ux.dev, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [cgroups?] [mm?] WARNING in memcg1_swapout

Hello,

syzbot found the following issue on:

HEAD commit:    0f853ca2a798 Add linux-next specific files for 20260113
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14f7259a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8d6e5303d96e21b5
dashboard link: https://syzkaller.appspot.com/bug?extid=079a3b213add54dd18a7
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=167ef922580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16d295fa580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/480cd223f3f6/disk-0f853ca2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1ca2f0dbb7cc/vmlinux-0f853ca2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/60a0fef5805b/bzImage-0f853ca2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+079a3b213add54dd18a7@...kaller.appspotmail.com

------------[ cut here ]------------
WARNING: mm/memcontrol-v1.c:642 at memcg1_swapout+0x6c2/0x8d0 mm/memcontrol-v1.c:642, CPU#0: syz.4.233/6746
Modules linked in:
CPU: 0 UID: 0 PID: 6746 Comm: syz.4.233 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:memcg1_swapout+0x6c2/0x8d0 mm/memcontrol-v1.c:642
Code: 6d 5d 0d 00 0f 85 01 fa ff ff 48 89 df 48 c7 c6 a0 c3 98 8b e8 bf 8c f8 fe c6 05 77 6d 5d 0d 01 90 0f 0b 90 e9 e2 f9 ff ff 90 <0f> 0b 90 e9 eb fb ff ff 90 0f 0b 90 41 80 3c 2e 00 0f 85 d5 fe ff
RSP: 0018:ffffc9000bbae718 EFLAGS: 00010002
RAX: 0000000000000004 RBX: ffffea00017e9100 RCX: ffff888021f5c150
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffc9000b59b404
RBP: dffffc0000000000 R08: ffffc9000b59b407 R09: 1ffff920016b3680
R10: dffffc0000000000 R11: fffff520016b3681 R12: ffffea00017e9108
R13: 1ffffd40002fd220 R14: 1ffffd40002fd221 R15: ffff88805398b178
FS:  00007fdd6c81a6c0(0000) GS:ffff888125bf7000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000009a000 CR3: 0000000075930000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __remove_mapping+0xac5/0xe30 mm/vmscan.c:764
 shrink_folio_list+0x28d8/0x5320 mm/vmscan.c:1542
 reclaim_folio_list+0xeb/0x4e0 mm/vmscan.c:2222
 reclaim_pages+0x454/0x520 mm/vmscan.c:2259
 madvise_cold_or_pageout_pte_range+0x19a0/0x1ce0 mm/madvise.c:563
 walk_pmd_range mm/pagewalk.c:130 [inline]
 walk_pud_range mm/pagewalk.c:224 [inline]
 walk_p4d_range mm/pagewalk.c:262 [inline]
 walk_pgd_range+0x1037/0x1d30 mm/pagewalk.c:303
 __walk_page_range+0x14c/0x710 mm/pagewalk.c:410
 walk_page_range_vma_unsafe+0x34c/0x400 mm/pagewalk.c:714
 madvise_pageout_page_range mm/madvise.c:622 [inline]
 madvise_pageout mm/madvise.c:647 [inline]
 madvise_vma_behavior+0x30c7/0x4420 mm/madvise.c:1366
 madvise_walk_vmas+0x575/0xaf0 mm/madvise.c:1721
 madvise_do_behavior+0x38e/0x550 mm/madvise.c:1937
 do_madvise+0x1bc/0x270 mm/madvise.c:2030
 __do_sys_madvise mm/madvise.c:2039 [inline]
 __se_sys_madvise mm/madvise.c:2037 [inline]
 __x64_sys_madvise+0xa7/0xc0 mm/madvise.c:2037
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdd6b98f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007fdd6c81a038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007fdd6bbe5fa0 RCX: 00007fdd6b98f749
RDX: 0000000000000015 RSI: 0000000000600000 RDI: 0000200000000000
RBP: 00007fdd6ba13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdd6bbe6038 R14: 00007fdd6bbe5fa0 R15: 00007ffcd3996008
 </TASK>


---
This report is generated by a bot. It may contain errors.
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