linux-kernel - Re: [BUG] PCI/DPC: NULL pointer dereference in pci_bus_read_config_dword during DPC recovery racing with hotplug

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Message-ID: <aWdtfj2ubHp41fRT@wunner.de>
Date: Wed, 14 Jan 2026 11:18:38 +0100
From: Lukas Wunner <lukas@...ner.de>
To: Kangfenglong <kangfenglong@...wei.com>
Cc: "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"shenyang (M)" <shenyang39@...wei.com>,
	"Zengtao (B)" <prime.zeng@...ilicon.com>,
	"shenjian (K)" <shenjian15@...wei.com>,
	"Wangyu (Eric)" <seven.wangyu@...wei.com>
Subject: Re: [BUG] PCI/DPC: NULL pointer dereference in
 pci_bus_read_config_dword during DPC recovery racing with hotplug

On Wed, Jan 14, 2026 at 09:49:44AM +0000, Kangfenglong wrote:
> Kernel Version: 5.10.0

That's ancient.

The bug you're seeing was fixed upstream with 11a1f4bc4736 ("PCI/DPC:
Fix use-after-free on concurrent DPC and hot-removal").  It was
backported to 5.10.224.

> 1. Existing synchronization between DPC and hotplug?

That was introduced by a97396c6eb13 ("PCI: pciehp: Ignore Link Down/Up
caused by DPC"), which went into v5.14.

Thanks,

Lukas