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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Mon, 18 Sep 2023 12:17:35 +0200
Message-ID: <CAJZ5v0gCEUmvbPQpJYJw6p_8KB1Jb3-bgcyBKZwdQReimZPw=g@mail.gmail.com>
Subject: Re: [PATCH v1] ACPI: processor_pdc: Fix uninitialized access of buf
To:     Michal Wilczynski <michal.wilczynski@intel.com>
Cc:     linux-acpi@vger.kernel.org, rafael@kernel.org,
        linux-kernel@vger.kernel.org, lenb@kernel.org
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On Fri, Sep 15, 2023 at 12:25 AM Michal Wilczynski
<michal.wilczynski@intel.com> wrote:
>
> Bug was introduced during unification of setting CAP_SMP_T_SWCOORD for
> _PDC and _OSC methods. Third u32 in buffer is never being zero-ed before
> setting bits on it. The memory is not guaranteed to be zero as it was
> allocated by kmalloc() instead of kzalloc(). Fix this by initializing
> third u32 in buffer to 0.
>
> Fixes: b9e8d0168a7a ("ACPI: processor: Set CAP_SMP_T_SWCOORD in arch_acpi_set_proc_cap_bits()")
> Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
> ---
>  drivers/acpi/processor_pdc.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/acpi/processor_pdc.c b/drivers/acpi/processor_pdc.c
> index 1a8591e9a9bf..994091bd52de 100644
> --- a/drivers/acpi/processor_pdc.c
> +++ b/drivers/acpi/processor_pdc.c
> @@ -19,6 +19,7 @@ static void acpi_set_pdc_bits(u32 *buf)
>  {
>         buf[0] = ACPI_PDC_REVISION_ID;
>         buf[1] = 1;
> +       buf[2] = 0;
>
>         /* Twiddle arch-specific bits needed for _PDC */
>         arch_acpi_set_proc_cap_bits(&buf[2]);
> --

Applied as 6.6-rc material, thanks!