Re: [PATCH] drm/xe: Add helper function to inject fault into ct_dead_capture()

[Jani Nikula <jani.nikula@linux.intel.com>]

On Tue, 29 Apr 2025, Satyanarayana K V P <satyanarayana.k.v.p@intel.com> wrote:
> When injecting fault to xe_guc_ct_send_recv() & xe_guc_mmio_send_recv()
> functions, the CI test systems are going out of space and crashing. To
> avoid this issue, a new helper function is created and when fault is injected
> into this xe_should_fail_ct_dead_capture() helper function, ct dead capture is
> avoided which suppresses ct dumps in the log.
>
> Signed-off-by: Satyanarayana K V P <satyanarayana.k.v.p@intel.com>
> Suggested-by: John Harrison <John.C.Harrison@Intel.com>
> Tested-by: Aditya Chauhan <aditya.chauhan@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_guc_ct.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
>
> diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
> index 2447de0ebedf..3a49e432f74a 100644
> --- a/drivers/gpu/drm/xe/xe_guc_ct.c
> +++ b/drivers/gpu/drm/xe/xe_guc_ct.c
> @@ -1770,6 +1770,12 @@ void xe_guc_ct_print(struct xe_guc_ct *ct, struct drm_printer *p, bool want_ctb)
>  }
>  
>  #if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
> +static noinline int xe_should_fail_ct_dead_capture(void)

IMO noinline needs an explanation. I can guess, but let's not make
everyone guess.

BR,
Jani.

> +{
> +	return 0;
> +}
> +ALLOW_ERROR_INJECTION(xe_should_fail_ct_dead_capture, ERRNO);
> +
>  static void ct_dead_capture(struct xe_guc_ct *ct, struct guc_ctb *ctb, u32 reason_code)
>  {
>  	struct xe_guc_log_snapshot *snapshot_log;
> @@ -1778,6 +1784,13 @@ static void ct_dead_capture(struct xe_guc_ct *ct, struct guc_ctb *ctb, u32 reaso
>  	unsigned long flags;
>  	bool have_capture;
>  
> +	/*
> +	 * Huge dump is getting generated when injecting error for guc CT/MMIO
> +	 * functions. So, let us suppress the dump when fault is injected.
> +	 */
> +	if (xe_should_fail_ct_dead_capture())
> +		return;
> +
>  	if (ctb)
>  		ctb->info.broken = true;

-- 
Jani Nikula, Intel