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Date: Wed, 8 Apr 2026 12:59:59 +0200
From: Lukas Wunner <lukas@wunner.de>
To: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	manivannan.sadhasivam@oss.qualcomm.com, linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] PCI: Fix NULL pointer access in
 pci_store_saved_state()
Message-ID: <adY1L6R88SLtpZzN@wunner.de>
References: <20260404-fix_pci_access-v1-0-416f32c6f7ec@oss.qualcomm.com>
 <20260404-fix_pci_access-v1-2-416f32c6f7ec@oss.qualcomm.com>
 <adIXJvrV1VRunFOu@wunner.de>
 <89dda312-92ff-4957-bf67-dd0b60f681b8@oss.qualcomm.com>
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In-Reply-To: <89dda312-92ff-4957-bf67-dd0b60f681b8@oss.qualcomm.com>

On Wed, Apr 08, 2026 at 03:16:28PM +0530, Krishna Chaitanya Chundru wrote:
> On 4/5/2026 1:32 PM, Lukas Wunner wrote:
> > On Sat, Apr 04, 2026 at 02:23:00PM +0530, Krishna Chaitanya Chundru wrote:
> > No, please validate values read from config space with
> > PCI_POSSIBLE_ERROR() before using them to access memory at
> > a location that may be out-of-bounds.  Or cache the size on
> > enumeration and avoid re-reading it upon pci_save_state().
> 
> pci_save_state() has many config reading having check for each read
> is not ideal way

The ask is not to guard every config space read with a check,
but only ones which are used to calculate the offset into a
memory allocation.  We only need to prevent out-of-bounds
memory accesses.  We do not need to prevent saving "all ones".

Thanks,

Lukas