Re: [PATCH v2] platform/x86/intel: pmc: fix ltr decode in pmc_core_ltr_show()

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

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On Fri, 24 Jan 2025, Dmitry Kandybka wrote:

> In pmc_core_ltr_show(), promote 'val' to 'u64' to avoid possible integer
> overflow. Values (10 bit) are multiplied by the scale, the result of
> expression is in a range from 1 to 34,326,183,936 which is bigger then
> UINT32_MAX. Compile tested only.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Signed-off-by: Dmitry Kandybka <d.kandybka@gmail.com>
> ---
> v1 -> v2: 'val' variable declared as 'u64' instead of type casting
> at usage points
> 
>  drivers/platform/x86/intel/pmc/core.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
> index 10f04b944117..1ee0fb5f8250 100644
> --- a/drivers/platform/x86/intel/pmc/core.c
> +++ b/drivers/platform/x86/intel/pmc/core.c
> @@ -626,8 +626,8 @@ static u32 convert_ltr_scale(u32 val)
>  static int pmc_core_ltr_show(struct seq_file *s, void *unused)
>  {
>  	struct pmc_dev *pmcdev = s->private;
> -	u64 decoded_snoop_ltr, decoded_non_snoop_ltr;
> -	u32 ltr_raw_data, scale, val;
> +	u64 decoded_snoop_ltr, decoded_non_snoop_ltr, val;
> +	u32 ltr_raw_data, scale;
>  	u16 snoop_ltr, nonsnoop_ltr;
>  	unsigned int i, index, ltr_index = 0;

Thanks for the update,

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

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