From 0cd8450c257faa0cece0e0c43d3b55d1a389acc7 Mon Sep 17 00:00:00 2001 From: Szymon Wilczek Date: Mon, 10 Aug 2026 21:23:44 +0200 Subject: [PATCH] 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. Fixes: 1a793caf6f69 ("hwmon: (coretemp) Use dynamic allocated memory for core temp_data") Signed-off-by: Szymon Wilczek Link: https://lore.kernel.org/r/20260810192344.3733721-1-swilczek.lx@gmail.com Signed-off-by: Guenter Roeck --- drivers/hwmon/coretemp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c index d47ba64788e1..5095eb057680 100644 --- a/drivers/hwmon/coretemp.c +++ b/drivers/hwmon/coretemp.c @@ -650,6 +650,7 @@ static void coretemp_device_remove(int zoneid) struct platform_data *pdata = platform_get_drvdata(pdev); ida_destroy(&pdata->ida); + kfree(pdata->core_data); kfree(pdata); platform_device_unregister(pdev); }