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Date: Tue, 4 Jun 2024 18:45:28 +0300
From: Imre Deak <imre.deak@intel.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Leon Romanovsky <leon@kernel.org>, Tejun Heo <tj@kernel.org>,
	Dave Jiang <dave.jiang@intel.com>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	Zqiang <qiang.zhang1211@gmail.com>, Gal Pressman <gal@nvidia.com>,
	Tariq Toukan <tariqt@nvidia.com>,
	RDMA mailing list <linux-rdma@vger.kernel.org>,
	Hillf Danton <hdanton@sina.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH -rc] workqueue: Reimplement UAF fix to avoid lockdep
 worning
Message-ID: <Zl82mAP7EakKzVRg@ideak-desk.fi.intel.com>
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 <Zl8k/8/yQLnZcGd3@ideak-desk.fi.intel.com>
 <665f30d54276e_4a4e629427@dwillia2-xfh.jf.intel.com.notmuch>
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On Tue, Jun 04, 2024 at 08:20:53AM -0700, Dan Williams wrote:
> Imre Deak wrote:
> > Hi,
> > 
> > [Sorry for the previous message, resending it now
> >  with proper In-reply-to: header added.]
> > 
> > I see a similar issue, a corruption in the lock_keys_hash while
> > alloc_workqueue()->lockdep_register_key() iterates it, see [1] for the
> > stacktrace.
> > 
> > Not sure if related or even will solve [1], but [2] will revert
> > 
> > commit 7e89efc6e9e4 ("PCI: Lock upstream bridge for pci_reset_function()")
> > 
> > which does
> > 
> > lockdep_register_key(&dev->cfg_access_key);
> > 
> > in pci_device_add() and doesn't unregister the key when the pci device is
> > removed (and potentially freed); so basically 7e89efc6e9e4 was missing a
> > 
> > lockdep_unregister_key();
> > 
> > in pci_destroy_dev().
> > 
> > Based on the above I wonder if 7e89efc6e9e4 could also lead to the
> > corruption of lock_keys_hash after a pci device is removed.o
> 
> Are you running with the revert applied and still seeing issues?

The revert is not yet applied and so [1] happened with a kernel
containing 7e89efc6e9e4.

[1] https://intel-gfx-ci.01.org/tree/drm-tip/IGT_7875/bat-atsm-1/dmesg0.txt