linux-kernel - [syzbot] [bcachefs?] WARNING: locking bug in srcu_gp_start_if

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Message-ID: <6838fe45.a00a0220.d8eae.0001.GAE@google.com>
Date: Thu, 29 May 2025 17:39:33 -0700
From: syzbot <syzbot+d7546350ee1d5ab2f7a8@...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: locking bug in srcu_gp_start_if_needed (2)

Hello,

syzbot found the following issue on:

HEAD commit:    d7fa1af5b33e Merge branch 'for-next/core' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=13d075f4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=89c13de706fbf07a
dashboard link: https://syzkaller.appspot.com/bug?extid=d7546350ee1d5ab2f7a8
compiler:       Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/da97ad659b2c/disk-d7fa1af5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/659e123552a8/vmlinux-d7fa1af5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6ec5dbf4643e/Image-d7fa1af5.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d7546350ee1d5ab2f7a8@...kaller.appspotmail.com

------------[ cut here ]------------
Looking for class "ACCESS_PRIVATE(sdp, lock)" with key init_srcu_struct_data.__key, but found a different class "&ACCESS_PRIVATE(sdp, lock)" with the same key
WARNING: CPU: 0 PID: 6492 at kernel/locking/lockdep.c:944 look_up_lock_class+0xf0/0x168 kernel/locking/lockdep.c:941
Modules linked in:
CPU: 0 UID: 0 PID: 6492 Comm: syz-executor Not tainted 6.15.0-rc7-syzkaller-gd7fa1af5b33e #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : look_up_lock_class+0xf0/0x168 kernel/locking/lockdep.c:941
lr : look_up_lock_class+0xf0/0x168 kernel/locking/lockdep.c:941
sp : ffff8000a2697520
x29: ffff8000a2697520 x28: 0000000000000000 x27: fffffdffbf6fe598
x26: ffff8000805a0df0 x25: 0000000000000001 x24: 0000000000000000
x23: ffff800096f71000 x22: 0000000000000000 x21: ffff800096fb4780
x20: fffffdffbf6fe598 x19: ffff800092b75178 x18: 1fffe0003386aa76
x17: 0000000000000000 x16: ffff80008adbe9e4 x15: 0000000000000001
x14: 1fffe0003386aae2 x13: 0000000000000000 x12: 0000000000000000
x11: ffff60003386aae3 x10: 0000000000ff0100 x9 : 75d53356a95e1300
x8 : 75d53356a95e1300 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff8000a2696e78 x4 : ffff80008f415ba0 x3 : ffff8000807b4b68
x2 : 0000000000000001 x1 : 0000000100000001 x0 : 0000000000000000
Call trace:
 look_up_lock_class+0xf0/0x168 kernel/locking/lockdep.c:941 (P)
 register_lock_class+0x48/0x348 kernel/locking/lockdep.c:1295
 __lock_acquire+0xa8/0x3058 kernel/locking/lockdep.c:5110
 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5866
 __raw_spin_trylock include/linux/spinlock_api_smp.h:90 [inline]
 _raw_spin_trylock+0x58/0xb0 kernel/locking/spinlock.c:138
 spin_lock_irqsave_sdp_contention kernel/rcu/srcutree.c:375 [inline]
 srcu_gp_start_if_needed+0x2c0/0x10d0 kernel/rcu/srcutree.c:1275
 __call_srcu kernel/rcu/srcutree.c:1389 [inline]
 __synchronize_srcu+0x2b8/0x348 kernel/rcu/srcutree.c:1441
 synchronize_srcu_expedited+0x24/0x34 kernel/rcu/srcutree.c:1467
 bch2_fs_btree_iter_exit+0x378/0x420 fs/bcachefs/btree_iter.c:3616
 __bch2_fs_free fs/bcachefs/super.c:564 [inline]
 bch2_fs_release+0x24c/0x72c fs/bcachefs/super.c:618
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x2b0/0x438 lib/kobject.c:737
 bch2_fs_free+0x308/0x378 fs/bcachefs/super.c:681
 bch2_kill_sb+0x48/0x58 fs/bcachefs/fs.c:2623
 deactivate_locked_super+0xc4/0x12c fs/super.c:473
 deactivate_super+0xe0/0x100 fs/super.c:506
 cleanup_mnt+0x31c/0x3ac fs/namespace.c:1431
 __cleanup_mnt+0x20/0x30 fs/namespace.c:1438
 task_work_run+0x1dc/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 do_notify_resume+0x16c/0x1ec arch/arm64/kernel/entry-common.c:151
 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
 el0_svc+0xb4/0x17c arch/arm64/kernel/entry-common.c:768
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
irq event stamp: 942766
hardirqs last  enabled at (942765): [<ffff80008addfa48>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
hardirqs last  enabled at (942765): [<ffff80008addfa48>] _raw_spin_unlock_irqrestore+0x38/0x98 kernel/locking/spinlock.c:194
hardirqs last disabled at (942766): [<ffff8000805a0de0>] spin_lock_irqsave_sdp_contention kernel/rcu/srcutree.c:375 [inline]
hardirqs last disabled at (942766): [<ffff8000805a0de0>] srcu_gp_start_if_needed+0x2b0/0x10d0 kernel/rcu/srcutree.c:1275
softirqs last  enabled at (940014): [<ffff8000803cf71c>] softirq_handle_end kernel/softirq.c:425 [inline]
softirqs last  enabled at (940014): [<ffff8000803cf71c>] handle_softirqs+0xaf8/0xc88 kernel/softirq.c:607
softirqs last disabled at (939939): [<ffff800080020efc>] __do_softirq+0x14/0x20 kernel/softirq.c:613
---[ end trace 0000000000000000 ]---


---
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