Re: [syzbot] [mm?] [bcachefs?] WARNING in lock_list_lru_of_memcg

[syzbot <syzbot+38a0cbd267eff2d286ff@syzkaller.appspotmail.com>]

syzbot has found a reproducer for the following issue on:

HEAD commit:    128c8f96eb86 Merge tag 'drm-fixes-2025-02-14' of https://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=148019a4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c776e555cfbdb82d
dashboard link: https://syzkaller.appspot.com/bug?extid=38a0cbd267eff2d286ff
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12328bf8580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-128c8f96.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a97f78ac821e/vmlinux-128c8f96.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f451cf16fc9f/bzImage-128c8f96.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/a7da783f97cf/mount_3.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+38a0cbd267eff2d286ff@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 5459 at mm/list_lru.c:96 lock_list_lru_of_memcg+0x39e/0x4d0 mm/list_lru.c:96
Modules linked in:
CPU: 0 UID: 0 PID: 5459 Comm: syz-executor Not tainted 6.14.0-rc2-syzkaller-00185-g128c8f96eb86 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:lock_list_lru_of_memcg+0x39e/0x4d0 mm/list_lru.c:96
Code: e9 19 fe ff ff e8 72 f2 b5 ff 4c 8b 7c 24 08 45 84 f6 0f 84 40 ff ff ff e9 22 01 00 00 e8 5a f2 b5 ff eb 05 e8 53 f2 b5 ff 90 <0f> 0b 90 eb 97 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c 71 fd ff ff 48
RSP: 0018:ffffc9000d70f3a0 EFLAGS: 00010293
RAX: ffffffff820bc50d RBX: 0000000000000000 RCX: ffff8880382d4880
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff8880351ac054 R08: ffffffff820bc49f R09: 1ffffffff2079b8e
R10: dffffc0000000000 R11: fffffbfff2079b8f R12: ffffffff820bc19e
R13: ffff88801ee9a798 R14: 0000000000000000 R15: ffff8880351ac000
FS:  000055557d70b500(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff6826de40 CR3: 000000005680c000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 list_lru_del+0x58/0x1f0 mm/list_lru.c:202
 list_lru_del_obj+0x17b/0x250 mm/list_lru.c:223
 d_lru_del fs/dcache.c:481 [inline]
 to_shrink_list+0x136/0x340 fs/dcache.c:904
 select_collect+0xce/0x1b0 fs/dcache.c:1472
 d_walk+0x1f5/0x750 fs/dcache.c:1295
 shrink_dcache_parent+0x144/0x3b0 fs/dcache.c:1527
 d_invalidate+0x11c/0x2d0 fs/dcache.c:1632
 proc_invalidate_siblings_dcache+0x3fb/0x6e0 fs/proc/inode.c:142
 release_task+0x168e/0x1830 kernel/exit.c:279
 wait_task_zombie kernel/exit.c:1249 [inline]
 wait_consider_task+0x1a14/0x2e60 kernel/exit.c:1476
 do_wait_thread kernel/exit.c:1539 [inline]
 __do_wait+0x1b0/0x850 kernel/exit.c:1657
 do_wait+0x1e9/0x550 kernel/exit.c:1691
 kernel_wait4+0x2a7/0x3e0 kernel/exit.c:1850
 __do_sys_wait4 kernel/exit.c:1878 [inline]
 __se_sys_wait4 kernel/exit.c:1874 [inline]
 __x64_sys_wait4+0x134/0x1e0 kernel/exit.c:1874
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f93f3983057
Code: 89 7c 24 10 48 89 4c 24 18 e8 45 1b 03 00 4c 8b 54 24 18 8b 54 24 14 41 89 c0 48 8b 74 24 08 8b 7c 24 10 b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 89 44 24 10 e8 95 1b 03 00 8b 44
RSP: 002b:00007fff6826e9b0 EFLAGS: 00000293 ORIG_RAX: 000000000000003d
RAX: ffffffffffffffda RBX: 0000000000000019 RCX: 00007f93f3983057
RDX: 0000000040000001 RSI: 00007fff6826ea1c RDI: 00000000ffffffff
RBP: 00007fff6826ea1c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000001388
R13: 00000000000927c0 R14: 000000000002f011 R15: 00007fff6826ea70
 </TASK>


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