linux-kernel - Re: [PATCH v3] PCI: keystone: Fix race condition when initializing PHYs

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: <20240109034159.GA3301517@rocinante>
Date: Tue, 9 Jan 2024 12:41:59 +0900
From: Krzysztof Wilczyński <kw@...ux.com>
To: Siddharth Vadapalli <s-vadapalli@...com>
Cc: lpieralisi@...nel.org, robh@...nel.org, bhelgaas@...gle.com,
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, ilpo.jarvinen@...ux.intel.com,
	vigneshr@...com, r-gunasekaran@...com, srk@...com
Subject: Re: [PATCH v3] PCI: keystone: Fix race condition when initializing
 PHYs

Hello,

> The PCI driver invokes the PHY APIs using the ks_pcie_enable_phy()
> function. The PHY in this case is the Serdes. It is possible that the
> PCI instance is configured for 2 lane operation across two different
> Serdes instances, using 1 lane of each Serdes. In such a configuration,
> if the reference clock for one Serdes is provided by the other Serdes,
> it results in a race condition. After the Serdes providing the reference
> clock is initialized by the PCI driver by invoking its PHY APIs, it is
> not guaranteed that this Serdes remains powered on long enough for the
> PHY APIs based initialization of the dependent Serdes. In such cases,
> the PLL of the dependent Serdes fails to lock due to the absence of the
> reference clock from the former Serdes which has been powered off by the
> PM Core.
> 
> Fix this by obtaining reference to the PHYs before invoking the PHY
> initialization APIs and releasing reference after the initialization is
> complete.

Applied to controller/keystone, thank you!

[1/1] PCI: keystone: Fix race condition when initializing PHYs
      https://git.kernel.org/pci/pci/c/c12ca110c613

	Krzysztof