linux-kernel - Re: [PATCH 1/2] PCI: dwc-debugfs: Perform deinit only when the debugfs is initialized

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Message-ID: <20250226065345.GB951736@rocinante>
Date: Wed, 26 Feb 2025 15:53:45 +0900
From: Krzysztof Wilczyński <kw@...ux.com>
To: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Cc: jingoohan1@...il.com, lpieralisi@...nel.org, robh@...nel.org,
	bhelgaas@...gle.com, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org, shradha.t@...sung.com,
	cassel@...nel.org
Subject: Re: [PATCH 1/2] PCI: dwc-debugfs: Perform deinit only when the
 debugfs is initialized

Hello,

> Some endpoint controller drivers like pcie-qcom-ep, pcie-tegra194 call
> dw_pcie_ep_cleanup() to cleanup the resources at the start of the PERST#
> deassert (due to refclk dependency). By that time, debugfs won't be
> registered, leading to NULL pointer dereference:
> 
> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
> Call trace:
> dwc_pcie_debugfs_deinit+0x18/0x38 (P)
> dw_pcie_ep_cleanup+0x2c/0x50
> qcom_pcie_ep_perst_irq_thread+0x278/0x5e8
> 
> So perform deinit only when the debugfs is initialized.

Good catch!  With that...

Reviewed-by: Krzysztof Wilczyński <kwilczynski@...nel.org>

Thank you!

	Krzysztof