[syzbot ci] Re: introduce uncharged file mapped folios

[syzbot ci <syzbot+ciacf14517a343602e@syzkaller.appspotmail.com>]

syzbot ci has tested the following series

[v2] introduce uncharged file mapped folios
https://lore.kernel.org/all/cover.1755300815.git.boris@bur.io
* [PATCH v2 1/3] mm/filemap: add AS_UNCHARGED
* [PATCH v2 2/3] mm: add vmstat for cgroup uncharged pages
* [PATCH v2 3/3] btrfs: set AS_UNCHARGED on the btree_inode

and found the following issue:
WARNING in folio_lruvec_lock_irqsave

Full report is available here:
https://ci.syzbot.org/series/15fd2538-1138-43c0-b4d6-6d7f53b0be69

***

WARNING in folio_lruvec_lock_irqsave

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      dfc0f6373094dd88e1eaf76c44f2ff01b65db851
arch:      amd64
compiler:  Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
config:    https://ci.syzbot.org/builds/5b3f7bc8-d0c2-4985-8ae6-d51ea4e2baed/config
C repro:   https://ci.syzbot.org/findings/f02552bd-e7e6-4c3f-8cc3-04a5a946771d/c_repro
syz repro: https://ci.syzbot.org/findings/f02552bd-e7e6-4c3f-8cc3-04a5a946771d/syz_repro

 do_new_mount+0x2a2/0x9e0 fs/namespace.c:3805
 do_mount fs/namespace.c:4133 [inline]
 __do_sys_mount fs/namespace.c:4344 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4321
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
------------[ cut here ]------------
WARNING: CPU: 0 PID: 5951 at ./include/linux/memcontrol.h:734 folio_lruvec include/linux/memcontrol.h:734 [inline]
WARNING: CPU: 0 PID: 5951 at ./include/linux/memcontrol.h:734 folio_lruvec_lock_irqsave+0x184/0x1d0 mm/memcontrol.c:1252
Modules linked in:
CPU: 0 UID: 0 PID: 5951 Comm: syz-executor Not tainted 6.17.0-rc1-syzkaller-00036-gdfc0f6373094-dirty #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:folio_lruvec include/linux/memcontrol.h:734 [inline]
RIP: 0010:folio_lruvec_lock_irqsave+0x184/0x1d0 mm/memcontrol.c:1252
Code: 74 0c 4c 89 f7 e8 cc 53 f8 ff 48 8b 04 24 49 89 06 eb a0 48 89 df 48 c7 c6 60 4e 98 8b e8 a4 36 fd fe c6 05 52 a1 62 0d 01 90 <0f> 0b 90 e9 a5 fe ff ff 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c 22
RSP: 0018:ffffc9000359f540 EFLAGS: 00010246
RAX: f0f9782cf8520600 RBX: ffffea0000807140 RCX: f0f9782cf8520600
RDX: 0000000000000002 RSI: ffffffff8dba6067 RDI: ffff888020a73980
RBP: ffffc9000359f5e0 R08: ffff88804b024253 R09: 1ffff1100960484a
R10: dffffc0000000000 R11: ffffed100960484b R12: ffff88804b032fe8
R13: ffff88801ba80918 R14: ffff888106950000 R15: 0000000000000000
FS:  0000555587fa3500(0000) GS:ffff8880b861c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00003e720 CR3: 0000000029a9c000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 folio_lruvec_relock_irqsave include/linux/memcontrol.h:1544 [inline]
 folio_batch_move_lru+0x20a/0x3a0 mm/swap.c:167
 lru_add_drain_cpu+0x119/0x880 mm/swap.c:647
 lru_add_drain+0x122/0x3e0 mm/swap.c:735
 __folio_batch_release+0x48/0x90 mm/swap.c:1054
 folio_batch_release include/linux/pagevec.h:101 [inline]
 invalidate_inode_pages2_range+0x889/0xa80 mm/truncate.c:707
 close_ctree+0x6ff/0x1380 fs/btrfs/disk-io.c:4408
 generic_shutdown_super+0x135/0x2c0 fs/super.c:643
 kill_anon_super+0x3b/0x70 fs/super.c:1282
 btrfs_kill_super+0x41/0x50 fs/btrfs/super.c:2114
 deactivate_locked_super+0xbc/0x130 fs/super.c:474
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1378
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a78b8ff17
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffe33fe80a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f4a78c11c05 RCX: 00007f4a78b8ff17
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe33fe8160
RBP: 00007ffe33fe8160 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe33fe91f0
R13: 00007f4a78c11c05 R14: 000000000000f471 R15: 00007ffe33fe9230
 </TASK>


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
Tested-by: syzbot@syzkaller.appspotmail.com

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