hwmon: (coretemp) Fix core count limitation

Bug #2056126 reported by Andrea Righi
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Fix Released
Undecided
Unassigned
Noble
Fix Released
Undecided
Unassigned

Bug Description

[Impact]

In linux 6.8 the coretemp driver supports at most 128 cores per package. Cores higher than 128 will lose their core temperature information.

There is an upstream patch set that allows to support more than 128 cores per package, but it's applied to linux-next for now and it's scheduled for 6.9.

We should apply the patch set to the Noble 6.8 kernel, so that we can properly support systems with a large amount of cores per package.

[Test case]

Read temperature info from /sys/class/hwmon on a system with > 128 cores per package (that means we don't have a proper test case to verify the fix at the moment).

[Fix]

Apply the following commits (from linux-next):

18cb15e9c108 hwmon: (coretemp) Use dynamic allocated memory for core temp_data
f0a5f46b0100 hwmon: (coretemp) Remove redundant temp_data->is_pkg_data
16a29729c00c hwmon: (coretemp) Split package temp_data and core temp_data
b48fddda2b30 hwmon: (coretemp) Abstract core_temp helpers
a30f3dc6e9bf hwmon: (coretemp) Remove redundant pdata->cpu_map[]
e416450cb080 hwmon: (coretemp) Replace sensor_device_attribute with device_attribute
46ee134971bb hwmon: (coretemp) Remove unnecessary dependency of array index
9f360b22929c hwmon: (coretemp) Introduce enum for attr index

[Regression potential]

We may experience hwmon-related regressions, either systems reading incorrect temperature information or even bugs/crashes when accessing data from /sys/class/hwmon.

Andrea Righi (arighi)
Changed in linux (Ubuntu Noble):
status: New → Fix Committed
Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package linux - 6.8.0-20.20

---------------
linux (6.8.0-20.20) noble; urgency=medium

  * noble/linux: 6.8.0-20.20 -proposed tracker (LP: #2058221)

  * Noble update: v6.8.1 upstream stable release (LP: #2058224)
    - x86/mmio: Disable KVM mitigation when X86_FEATURE_CLEAR_CPU_BUF is set
    - Documentation/hw-vuln: Add documentation for RFDS
    - x86/rfds: Mitigate Register File Data Sampling (RFDS)
    - KVM/x86: Export RFDS_NO and RFDS_CLEAR to guests
    - Linux 6.8.1

  * Autopkgtest failures on amd64 (LP: #2048768)
    - [Packaging] update to clang-18

  * Miscellaneous Ubuntu changes
    - SAUCE: apparmor4.0.0: LSM stacking v39: fix build error with
      CONFIG_SECURITY=n
    - [Config] amd64: MITIGATION_RFDS=y

 -- Paolo Pisati <email address hidden> Mon, 18 Mar 2024 11:08:14 +0100

Changed in linux (Ubuntu Noble):
status: Fix Committed → Fix Released
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