linux-kernel - Re: [PATCH 1/1] PCI/bwctrl: Fix link speed return type

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] [day] [month] [year] [list]

Message-ID: <20250321171319.GA1132947@bhelgaas>
Date: Fri, 21 Mar 2025 12:13:19 -0500
From: Bjorn Helgaas <helgaas@...nel.org>
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>,
	Jonathan Cameron <Jonathan.Cameron@...wei.com>,
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] PCI/bwctrl: Fix link speed return type

On Fri, Mar 21, 2025 at 06:31:03PM +0200, Ilpo Järvinen wrote:
> pcie_bwctrl_select_speed() should take __fls() of the speed bit, not
> return it as a raw value. Instead of directly returning 2.5GT/s speed
> bit, simply assign the fallback speed (2.5GT/s) into supported_speeds
> variable to share the normal return path that calls
> pcie_supported_speeds2target_speed() to calculate __fls().
> 
> This code path is not very likely to execute because
> pcie_get_supported_speeds() should provide valid ->supported_speeds but
> a spec violating device could fail to synthetize any speed in
> pcie_get_supported_speeds(). It could also happen in case the
> supported_speeds intersection is empty (also a violation of the current
> PCIe specs).
> 
> Fixes: de9a6c8d5dbf ("PCI/bwctrl: Add pcie_set_target_speed() to set PCIe Link Speed")
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>

Applied to pci/bwctrl for v6.15, thanks!

> ---
>  drivers/pci/pcie/bwctrl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/pcie/bwctrl.c b/drivers/pci/pcie/bwctrl.c
> index 0a5e7efbce2c..58ba8142c9a3 100644
> --- a/drivers/pci/pcie/bwctrl.c
> +++ b/drivers/pci/pcie/bwctrl.c
> @@ -113,7 +113,7 @@ static u16 pcie_bwctrl_select_speed(struct pci_dev *port, enum pci_bus_speed spe
>  		up_read(&pci_bus_sem);
>  	}
>  	if (!supported_speeds)
> -		return PCI_EXP_LNKCAP2_SLS_2_5GB;
> +		supported_speeds = PCI_EXP_LNKCAP2_SLS_2_5GB;
>  
>  	return pcie_supported_speeds2target_speed(supported_speeds & desired_speeds);
>  }
> 
> base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b
> -- 
> 2.39.5
>