ACK: [PATCH] s3: fix segmentation fault when PM_S2IDLE_SLP_S0 is not available (LP: #1894229)

[ivanhu]

On 9/5/20 12:17 AM, Colin King wrote:
> From: Colin Ian King <colin.king at canonical.com>
> 
> Currently if PM_S2IDLE_SLP_S0 is not available then atoi() is called
> on a NULL pointer causing a segmentation fault.  If it is available
> there string returned is leaked.  Fix these two bugs by adding a helper
> function to read the PM_S2IDLE_SLP_S0 file and return 0 if it is not
> possible or the residency value if it is available.
> 
> Fixes: 69c18bab0cc0 ("s3: check slp_s0_residency_usec for s2idle")
> Signed-off-by: Colin Ian King <colin.king at canonical.com>
> ---
>  src/acpi/s3/s3.c | 23 +++++++++++++++++++++--
>  1 file changed, 21 insertions(+), 2 deletions(-)
> 
> diff --git a/src/acpi/s3/s3.c b/src/acpi/s3/s3.c
> index fc6186a4..997ac83f 100644
> --- a/src/acpi/s3/s3.c
> +++ b/src/acpi/s3/s3.c
> @@ -206,6 +206,25 @@ static int wrap_pmutils_do_suspend(fwts_pm_method_vars *fwts_settings,
>  	return status;
>  }
>  
> +/*
> + *  get_s2_idle_residency()
> + *	read PM_S2IDLE_SLP_S0, return 0 if it is not available
> + */
> +static uint32_t get_s2_idle_residency(void)
> +{
> +	char *str;
> +	uint32_t val;
> +
> +	str = fwts_get(PM_S2IDLE_SLP_S0);
> +	if (!str)
> +		return 0;
> +
> +	val = atoi(str);
> +	free(str);
> +
> +	return val;
> +}
> +
>  static int s3_do_suspend_resume(fwts_framework *fw,
>  	int *hw_errors,
>  	int *pm_errors,
> @@ -336,7 +355,7 @@ static int s3_do_suspend_resume(fwts_framework *fw,
>  	}
>  
>  	if (!strncmp(sleep_type, "s2idle", strlen("s2idle"))) {
> -		uint32_t residency = atoi(fwts_get(PM_S2IDLE_SLP_S0));
> +		uint32_t residency = get_s2_idle_residency();
>  		bool intel;
>  		if (fwts_cpu_is_Intel(&intel) == FWTS_OK && intel && residency <= *s2idle_residency) {
>  			(*s2idle_errors)++;
> @@ -545,7 +564,7 @@ static int s3_test_multiple(fwts_framework *fw)
>  	int resume_too_long = 0;
>  	int awake_delay = s3_min_delay * 1000;
>  	int delta = (int)(s3_delay_delta * 1000.0);
> -	uint32_t s2idle_residency = atoi(fwts_get(PM_S2IDLE_SLP_S0));
> +	uint32_t s2idle_residency = get_s2_idle_residency();
>  	int pm_debug;
>  
>  #if FWTS_ENABLE_LOGIND
> 

Acked-by: Ivan Hu <ivan.hu at canonical.com>