[PATCH v2] platform/x86: intel_telemetry: initialize default trace verbosity

[PATCH v2] platform/x86: intel_telemetry: initialize default trace verbosity

[Aleksandrova Alyona]

telemetry_def_get_trace_verbosity() returns success without initializing
the output verbosity value.

The default telemetry operations are installed when the core driver is
initialized and again by telemetry_clear_pltdata() when the platform
driver is removed. The telemetry debugfs files can remain available after
the platform driver removal.

A subsequent read of pss_trace_verbosity or ioss_trace_verbosity calls
telemetry_get_trace_verbosity(), which may use the default callback and
return success without setting verbosity. The uninitialized value is then
passed to seq_printf().

Validate the output pointer and initialize the default verbosity to zero
so callers never use an uninitialized value after a successful call.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 378f956e3f93 ("platform/x86: Add Intel Telemetry Core Driver")
Signed-off-by: Aleksandrova Alyona <aga@itb.spb.ru>
---
 drivers/platform/x86/intel/telemetry/core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/platform/x86/intel/telemetry/core.c b/drivers/platform/x86/intel/telemetry/core.c
index f312864b8d07a..62299524a07b2 100644
--- a/drivers/platform/x86/intel/telemetry/core.c
+++ b/drivers/platform/x86/intel/telemetry/core.c
@@ -24,6 +24,10 @@ static struct telemetry_core_config telm_core_conf;
 static int telemetry_def_get_trace_verbosity(enum telemetry_unit telem_unit,
 					     u32 *verbosity)
 {
+	if (!verbosity)
+		return -EINVAL;
+
+	*verbosity = 0;
 	return 0;
 }
 
-- 
2.26.2

Re: [PATCH v2] platform/x86: intel_telemetry: initialize default trace verbosity

[Ilpo Järvinen]

On Tue, 15 Sep 2026, Aleksandrova Alyona wrote:

> telemetry_def_get_trace_verbosity() returns success without initializing
> the output verbosity value.
> 
> The default telemetry operations are installed when the core driver is
> initialized and again by telemetry_clear_pltdata() when the platform
> driver is removed. The telemetry debugfs files can remain available after
> the platform driver removal.
> 
> A subsequent read of pss_trace_verbosity or ioss_trace_verbosity calls
> telemetry_get_trace_verbosity(), which may use the default callback and
> return success without setting verbosity. The uninitialized value is then
> passed to seq_printf().
> 
> Validate the output pointer and initialize the default verbosity to zero
> so callers never use an uninitialized value after a successful call.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 378f956e3f93 ("platform/x86: Add Intel Telemetry Core Driver")
> Signed-off-by: Aleksandrova Alyona <aga@itb.spb.ru>
> ---

You're missing the information on what is changed in v2?!

>  drivers/platform/x86/intel/telemetry/core.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/platform/x86/intel/telemetry/core.c b/drivers/platform/x86/intel/telemetry/core.c
> index f312864b8d07a..62299524a07b2 100644
> --- a/drivers/platform/x86/intel/telemetry/core.c
> +++ b/drivers/platform/x86/intel/telemetry/core.c
> @@ -24,6 +24,10 @@ static struct telemetry_core_config telm_core_conf;
>  static int telemetry_def_get_trace_verbosity(enum telemetry_unit telem_unit,
>  					     u32 *verbosity)
>  {
> +	if (!verbosity)
> +		return -EINVAL;
> +
> +	*verbosity = 0;
>  	return 0;
>  }
>  
> 

-- 
 i.