linux-kernel - [syzbot] [bcachefs?] WARNING in lookup_object_or

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Message-ID: <683b1ba9.a00a0220.d8eae.0019.GAE@google.com>
Date: Sat, 31 May 2025 08:09:29 -0700
From: syzbot <syzbot+88e6a26b68fb670364e1@...kaller.appspotmail.com>
To: kent.overstreet@...ux.dev, linux-bcachefs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [bcachefs?] WARNING in lookup_object_or_alloc

Hello,

syzbot found the following issue on:

HEAD commit:    015a99fa7665 Merge tag 'nolibc-20250526-for-6.16-1' of git..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16fcedf4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=231a962e5fdb804b
dashboard link: https://syzkaller.appspot.com/bug?extid=88e6a26b68fb670364e1
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f68bd0ec2940/disk-015a99fa.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8c78735943b8/vmlinux-015a99fa.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7d9332085f01/bzImage-015a99fa.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+88e6a26b68fb670364e1@...kaller.appspotmail.com

ODEBUG: object ffffc9000d537a98 is on stack ffffc9000d530000, but NOT annotated.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 16496 at lib/debugobjects.c:655 debug_object_is_on_stack lib/debugobjects.c:655 [inline]
WARNING: CPU: 1 PID: 16496 at lib/debugobjects.c:655 lookup_object_or_alloc.part.0+0x2b1/0x590 lib/debugobjects.c:688
Modules linked in:
CPU: 1 UID: 0 PID: 16496 Comm: bch-copygc/loop Not tainted 6.15.0-syzkaller-02443-g015a99fa7665 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:debug_object_is_on_stack lib/debugobjects.c:655 [inline]
RIP: 0010:lookup_object_or_alloc.part.0+0x2b1/0x590 lib/debugobjects.c:688
Code: 0e 48 8d 7d 20 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 58 02 00 00 48 8b 55 20 4c 89 e6 48 c7 c7 c0 07 f5 8b e8 60 ff bf fc 90 <0f> 0b 90 48 83 c4 18 48 89 d8 5b 5d 41 5c 41 5d 41 5e 41 5f e9 b1
RSP: 0018:ffffc9000d5377b0 EFLAGS: 00010086
RAX: 0000000000000050 RBX: ffff8880347347a8 RCX: ffffffff819a71b9
RDX: 0000000000000000 RSI: ffffffff819af046 RDI: 0000000000000005
RBP: ffff88801f7e3c00 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000001 R11: 0000000000002be0 R12: ffffc9000d537a98
R13: ffff88801f7e3c00 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124aaa000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdb0980f000 CR3: 0000000030dfd000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 lookup_object_or_alloc lib/debugobjects.c:665 [inline]
 __debug_object_init+0x2a9/0x3d0 lib/debugobjects.c:743
 __init_work+0x4c/0x60 kernel/workqueue.c:677
 rhashtable_init_noprof+0x49f/0x7e0 lib/rhashtable.c:1085
 bch2_copygc_thread+0xf6/0xdd0 fs/bcachefs/movinggc.c:355
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


---
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