Linux 5.9 Exposes Device Link Details Via Sysfs, Allows Hiding DebugFS From User-Space

Written by Michael Larabel in Linux Kernel on 7 August 2020 at 11:29 AM EDT. 1 Comment
There are a few driver core changes for the Linux 5.9 kernel worth mentioning.

Exciting changes to the core driver infrastructure for the mainline Linux kernel are rare though this time around are a few alterations worth pointing out:

- The recently covered work by Sony on being able to allow restricting user-space access to DebugFS while keeping the debug feature enabled is in Linux 5.9. While most distributions / Linux configurations already restrict DebugFS access to root / admin privileges, as this file-system often exposes sensitive system information, the change by Sony allows for it to be initialized but not accessible from user-space. Sony's focus on this effort appears to be in line of further securing their Android smartphones.

- Another change with Linux 5.9, this time by Google, is exposing of device link details under sysfs. This allows better mapping and understanding if one device is a supplier or consumer to another. Details on the exposed device topology under sysfs via this patch.

- There is now a device probe log helper so drivers can report problems in a more unified manner.

There are also other driver core changes as outlined via the pull request that is already merged to mainline Linux 5.9.
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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

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