linux-kernel - Re: [syzbot] [xfs?] KASAN: slab-use-after-free Read in xfs_buf

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Message-ID: <69032607.050a0220.3344a1.043e.GAE@google.com>
Date: Thu, 30 Oct 2025 01:47:03 -0700
From: syzbot <syzbot+0391d34e801643e2809b@...kaller.appspotmail.com>
To: hch@...radead.org, linux-kernel@...r.kernel.org, linux-xfs@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [xfs?] KASAN: slab-use-after-free Read in xfs_buf_rele (4)

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: MAX_LOCKDEP_CHAINS too low!

BUG: MAX_LOCKDEP_CHAINS too low!
turning off the locking correctness validator.
CPU: 1 UID: 0 PID: 2577 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
Workqueue: xfs-cil/loop0 xlog_cil_push_work
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 add_chain_cache kernel/locking/lockdep.c:-1 [inline]
 lookup_chain_cache_add kernel/locking/lockdep.c:3855 [inline]
 validate_chain kernel/locking/lockdep.c:3876 [inline]
 __lock_acquire+0xf9c/0x30a4 kernel/locking/lockdep.c:5237
 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x5c/0x7c kernel/locking/spinlock.c:162
 __wake_up_common_lock kernel/sched/wait.c:124 [inline]
 __wake_up+0x40/0x1a8 kernel/sched/wait.c:146
 xlog_cil_set_ctx_write_state+0x2a8/0x310 fs/xfs/xfs_log_cil.c:997
 xlog_write+0x1fc/0xe94 fs/xfs/xfs_log.c:2252
 xlog_cil_write_commit_record fs/xfs/xfs_log_cil.c:1118 [inline]
 xlog_cil_push_work+0x19ec/0x1f74 fs/xfs/xfs_log_cil.c:1434
 process_one_work+0x7e8/0x155c kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x958/0xed8 kernel/workqueue.c:3400
 kthread+0x5fc/0x75c kernel/kthread.c:463
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844

Tested on:

commit:         af1722bb xfs: switch (back) to a per-buftarg buffer hash
git tree:       git://git.infradead.org/users/hch/misc.git xfs-buf-hash
console output: https://syzkaller.appspot.com/x/log.txt?x=1110bfe2580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=39f8a155475bc42d
dashboard link: https://syzkaller.appspot.com/bug?extid=0391d34e801643e2809b
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64

Note: no patches were applied.