Re: [PATCH v2 2/2] drm/xe/guc: Synchronize Dead CT worker with unbind

["Vivekanandan, Balasubramani" <balasubramani.vivekanandan@intel.com>]

On 30.10.2025 23:08, Summers, Stuart wrote:
> On Thu, 2025-10-30 at 20:41 +0530, Balasubramani Vivekanandan wrote:
> > Cancel and wait for any Dead CT worker to complete before continuing
> > with device unbinding. Else the worker will end up using resources
> > freed
> > by the undind operation.
> 
> /s/undind/unbind/
> 
> And similar here - can you provide a stack trace?

Unfortunately I didn't save the stack trace. Kernel panic happened in
Dead CT worker after I applied the fix from the first patch and retried
the use case. Also the issue becomes sporadic after the first patch.

Regards,
Bala

> 
> Thanks,
> Stuart
> 
> > 
> > Cc: Zhanjun Dong <zhanjun.dong@intel.com>
> > Fixes: d2c5a5a926f4 ("drm/xe/guc: Dead CT helper")
> > Signed-off-by: Balasubramani Vivekanandan
> > <balasubramani.vivekanandan@intel.com>
> > ---
> >  drivers/gpu/drm/xe/xe_guc_ct.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c
> > b/drivers/gpu/drm/xe/xe_guc_ct.c
> > index e68953ef3a00..536433b061fc 100644
> > --- a/drivers/gpu/drm/xe/xe_guc_ct.c
> > +++ b/drivers/gpu/drm/xe/xe_guc_ct.c
> > @@ -199,6 +199,9 @@ static void guc_ct_fini(struct drm_device *drm,
> > void *arg)
> >  {
> >         struct xe_guc_ct *ct = arg;
> >  
> > +#if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
> > +       cancel_work_sync(&ct->dead.worker);
> > +#endif
> >         ct_exit_safe_mode(ct);
> >         destroy_workqueue(ct->g2h_wq);
> >         xa_destroy(&ct->fence_lookup);
>