CVE-2026-90178hwmon: (coretemp) Fix core_data leak on CPUs without PTS

Official description

In the Linux kernel, the following vulnerability has been resolved: hwmon: (coretemp) Fix core_data leak on CPUs without PTS pdata->core_data is allocated in init_temp_data() when the first core temp_data of a package is created, but it is only released from destroy_temp_data(), and only in the branch that handles the package temp_data. Package temp_data is created solely when the CPU supports X86_FEATURE_PTS. On a CPU without it, coretemp_cpu_online() never calls coretemp_add_core() with pkg_flag set, so pdata->pkg_data stays NULL. coretemp_cpu_offline() then skips the removal of the package interface, destroy_temp_data() is never called for package data, and the array is still allocated when coretemp_device_remove() frees the platform data that pointed at it. Release the array in coretemp_device_remove(). destroy_temp_data() sets pdata->core_data to NULL when it frees it, so the added kfree() is a no-op on CPUs that do have PTS. Tested on an Intel Core i5-1135G7. The driver was instrumented to log every allocation and release of pdata->core_data, and the PTS check in coretemp_cpu_online() was patched out to emulate a CPU without package thermal support. Without this change the array was allocated and never released, and coretemp_device_remove() still saw a non-NULL pointer. With it the array is released and the pointer accounting balances. On an unmodified build the release still happens via the package temp_data and the added kfree() sees NULL, with no slab warnings over repeated module load and unload cycles.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/dc0d79b1be384e7f6a2308356afd10dcf3bf940f
• https://git.kernel.org/stable/c/86c1617b7d4b001b20a71deda3c791538a4fa6aa
• https://git.kernel.org/stable/c/9b23a010a1e8232974617c412cb9f578f3378b70
• https://git.kernel.org/stable/c/0cd8450c257faa0cece0e0c43d3b55d1a389acc7