Re: [PATCH 2/3] hwmon: (coretemp) Set nr_cores only after core_data allocation succeeds

[sashiko-bot@kernel.org]

> In init_temp_data(), pdata->nr_cores is populated from
> topology_num_cores_per_package() before allocating pdata->core_data. If
> that allocation fails, init_temp_data() returns NULL with
> pdata->core_data still NULL and pdata->nr_cores set to a positive value.
> 
> coretemp_add_core() logs the error without failing coretemp_cpu_online(),
> so the CPU still comes online with pdata->hwmon_dev registered. When the
> CPU is later taken offline (or the module is unloaded),
> coretemp_cpu_offline() calls get_temp_data(pd, cpu), which loops up to
> pdata->nr_cores and dereferences the NULL pdata->core_data pointer.
> 
> Store the core count in a local variable and assign pdata->nr_cores only
> after pdata->core_data is allocated, preserving the invariant that
> pdata->nr_cores is zero whenever pdata->core_data is NULL.
> 
> Reported-by: Sashiko <sashiko-bot@kernel.org>
> Fixes: 1a793caf6f69 ("hwmon: (coretemp) Use dynamic allocated memory for core temp_data")
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261031153528.3195123-1-linux@roeck-us.net?part=2