[syzbot] [mm?] [cgroups?] kernel BUG in swap_cgroup_record (2)

[syzbot <syzbot+d97580a8cceb9b03c13e@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    f8f97927abf7 Add linux-next specific files for 20260105
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=131ff69a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a0672dd8d69c3235
dashboard link: https://syzkaller.appspot.com/bug?extid=d97580a8cceb9b03c13e
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=17065efc580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=176c9e9a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1837bbc8e23e/disk-f8f97927.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/07390717f7e4/vmlinux-f8f97927.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8f4a72ec80dc/bzImage-f8f97927.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d97580a8cceb9b03c13e@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at mm/swap_cgroup.c:78!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6176 Comm: syz.0.30 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:swap_cgroup_record+0x19c/0x1c0 mm/swap_cgroup.c:78
Code: 02 e9 6d ff ff ff 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c 35 ff ff ff 4c 89 f7 e8 cf 84 f6 ff e9 28 ff ff ff e8 e5 c1 8f ff 90 <0f> 0b e8 dd c1 8f ff 4c 89 f7 48 c7 c6 80 f6 98 8b e8 de d4 f6 fe
RSP: 0018:ffffc90003176720 EFLAGS: 00010093
RAX: ffffffff8231359b RBX: 0000000000001b88 RCX: ffff8880351f9e40
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200062ecd4 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffc900041b1000 R15: 0000000000000002
FS:  00007feeba18f6c0(0000) GS:ffff8881259c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feeba18ef98 CR3: 0000000077742000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 memcg1_swapout+0x2fa/0x830 mm/memcontrol-v1.c:623
 __remove_mapping+0xac5/0xe30 mm/vmscan.c:773
 shrink_folio_list+0x2786/0x4f40 mm/vmscan.c:1528
 reclaim_folio_list+0xeb/0x4e0 mm/vmscan.c:2208
 reclaim_pages+0x454/0x520 mm/vmscan.c:2245
 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+0x3132/0x4170 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: 0033:0x7feeb938f749
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:00007feeba18f038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007feeb95e6090 RCX: 00007feeb938f749
RDX: 0000000000000015 RSI: 0000000000800000 RDI: 0000200000000000
RBP: 00007feeb9413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007feeb95e6128 R14: 00007feeb95e6090 R15: 00007ffd48399048
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:swap_cgroup_record+0x19c/0x1c0 mm/swap_cgroup.c:78
Code: 02 e9 6d ff ff ff 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c 35 ff ff ff 4c 89 f7 e8 cf 84 f6 ff e9 28 ff ff ff e8 e5 c1 8f ff 90 <0f> 0b e8 dd c1 8f ff 4c 89 f7 48 c7 c6 80 f6 98 8b e8 de d4 f6 fe
RSP: 0018:ffffc90003176720 EFLAGS: 00010093
RAX: ffffffff8231359b RBX: 0000000000001b88 RCX: ffff8880351f9e40
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200062ecd4 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffc900041b1000 R15: 0000000000000002
FS:  00007feeba18f6c0(0000) GS:ffff8881259c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feeba18ef98 CR3: 0000000077742000 CR4: 00000000003526f0


---
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