Re: [PATCH] drm/xe/guc: Fix CFI violation in debugfs access.

[Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>]

On 1/26/2026 3:21 PM, Michal Wajdeczko wrote:
>
> On 1/27/2026 12:10 AM, Daniele Ceraolo Spurio wrote:
>> xe_guc_print_info is void-returning, but the function pointer it is
>> assigned to expects an int-returning function, leading to the following
>> CFI error:
>>
>> [  206.873690] CFI failure at guc_debugfs_show+0xa1/0xf0 [xe]
>> (target: xe_guc_print_info+0x0/0x370 [xe]; expected type: 0xbe3bc66a)
>>
>> Fix this by using a local int-returning function, like we do for the
>> other debugfs entries in the same file.
> or maybe better option would be to fix the xe_guc_print_info() signature and return int ?
> then we will be able to correctly handle this forcewake error there:
>
>          err = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
>          if (err)
> -               return;
> +               return err;

That was actually what I had in my first local rev, but then I switched 
to this approach because every other entry in this file was handled that 
way. I'll switch back to returning int from xe_guc_print_info

Daniele

>
>> Fixes: e15826bb3c2c ("drm/xe/guc: Refactor GuC debugfs initialization")
>> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
>> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
>> Cc: George D Sworo <george.d.sworo@intel.com>
>> ---
>>   drivers/gpu/drm/xe/xe_guc_debugfs.c | 8 +++++++-
>>   1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_guc_debugfs.c b/drivers/gpu/drm/xe/xe_guc_debugfs.c
>> index 2f23119686d4..1a4c940ebecb 100644
>> --- a/drivers/gpu/drm/xe/xe_guc_debugfs.c
>> +++ b/drivers/gpu/drm/xe/xe_guc_debugfs.c
>> @@ -74,6 +74,12 @@ static int guc_debugfs_show(struct seq_file *m, void *data)
>>   	return print(&gt->uc.guc, &p);
>>   }
>>   
>> +static int guc_info(struct xe_guc *guc, struct drm_printer *p)
>> +{
>> +	xe_guc_print_info(guc, p);
>> +	return 0;
>> +}
>> +
>>   static int guc_log(struct xe_guc *guc, struct drm_printer *p)
>>   {
>>   	xe_guc_log_print(&guc->log, p);
>> @@ -110,7 +116,7 @@ static int guc_pc(struct xe_guc *guc, struct drm_printer *p)
>>    * - without access to the PF specific GuC objects
>>    */
>>   static const struct drm_info_list vf_safe_debugfs_list[] = {
>> -	{ "guc_info", .show = guc_debugfs_show, .data = xe_guc_print_info },
>> +	{ "guc_info", .show = guc_debugfs_show, .data = guc_info },
>>   	{ "guc_ctb", .show = guc_debugfs_show, .data = guc_ctb },
>>   };
>>