linux-ext4 - Re: Lockdep warnings on kexec (virtio

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <87a5d0aibc.ffs@tglx>
Date: Thu, 12 Dec 2024 19:04:55 +0100
From: Thomas Gleixner <tglx@...utronix.de>
To: David Woodhouse <dwmw2@...radead.org>, Stefan Hajnoczi
 <stefanha@...hat.com>, Jason Wang <jasowang@...hat.com>
Cc: "x86@...nel.org" <x86@...nel.org>, hpa <hpa@...or.com>, dyoung
 <dyoung@...hat.com>, kexec <kexec@...ts.infradead.org>, linux-ext4
 <linux-ext4@...r.kernel.org>, "Michael S. Tsirkin" <mst@...hat.com>,
 Stefano Garzarella <sgarzare@...hat.com>, eperezma <eperezma@...hat.com>,
 Paolo Bonzini <bonzini@...hat.com>, ming.lei@...hat.com, Petr Mladek
 <pmladek@...e.com>, John Ogness <jogness@...utronix.de>, Peter Zijlstra
 <peterz@...radead.org>
Subject: Re: Lockdep warnings on kexec (virtio_blk, hrtimers)

On Thu, Dec 12 2024 at 13:46, David Woodhouse wrote:
> On Thu, 2024-12-12 at 14:34 +0100, Thomas Gleixner wrote:
>> 
>> David, can you retest with the debug patch below? That should pin-point
>> the real culprit.
>
> B[    1.545489] ------------[ cut here ]------------
> [    1.546338] DEBUG_LOCKS_WARN_ON(suspend_syscore_active)
> [    1.546375] WARNING: CPU: 0 PID: 18 at kernel/locking/lockdep.c:4471 lockdep_hardirqs_on+0x13a/0x140

Now this starts to be completely mysterious:

> [    1.571399]  finish_task_switch.isra.0+0xc4/0x2d0
> [    1.572062]  __schedule+0x50a/0x1a10

How on earth did this end up in schedule() on the rcu_gp_kthread between
syscore_suspend() and syscore_resume()?

> [    1.575896]  rcu_gp_fqs_loop+0x10b/0x5b0
> [    1.576455]  ? _raw_spin_unlock_irq+0x28/0x50
> [    1.577072]  rcu_gp_kthread+0xf8/0x1b0
> [    1.577621]  kthread+0xd5/0x100
> [    1.578066]  ? __pfx_kthread+0x10/0x10

I tried to reproduce, but failed. Do you have a simple reproducer
recipe?

Thanks,

        tglx