On Fri, Mar 17, 2017 at 07:47:23AM +0000, Tvrtko Ursulin wrote: > > On 16/03/2017 20:42, Chris Wilson wrote: > >trace_i915_gem_request_out may be used after the request is completed, > >and so the request may have been retired on another thread, invalidating > >the rq->ctx. Avoid dereferencing rq->ctx in the tracepoint by switching > >to the fence context id instead, updating all tracepoints to match. > > > >Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > >Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > >--- > > drivers/gpu/drm/i915/i915_trace.h | 8 ++++---- > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > >diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h > >index 5503f5ab1e98..66404c5aee82 100644 > >--- a/drivers/gpu/drm/i915/i915_trace.h > >+++ b/drivers/gpu/drm/i915/i915_trace.h > >@@ -590,7 +590,7 @@ TRACE_EVENT(i915_gem_request_queue, > > TP_fast_assign( > > __entry->dev = req->i915->drm.primary->index; > > __entry->ring = req->engine->id; > >- __entry->ctx = req->ctx->hw_id; > >+ __entry->ctx = req->fence.context; > > __entry->seqno = req->fence.seqno; > > __entry->flags = flags; > > ), > >@@ -637,8 +637,8 @@ DECLARE_EVENT_CLASS(i915_gem_request, > > > > TP_fast_assign( > > __entry->dev = req->i915->drm.primary->index; > >- __entry->ctx = req->ctx->hw_id; > > __entry->ring = req->engine->id; > >+ __entry->ctx = req->fence.context; > > __entry->seqno = req->fence.seqno; > > __entry->global = req->global_seqno; > > ), > >@@ -681,7 +681,7 @@ DECLARE_EVENT_CLASS(i915_gem_request_hw, > > TP_fast_assign( > > __entry->dev = req->i915->drm.primary->index; > > __entry->ring = req->engine->id; > >- __entry->ctx = req->ctx->hw_id; > >+ __entry->ctx = req->fence.context; > > __entry->seqno = req->fence.seqno; > > __entry->global_seqno = req->global_seqno; > > __entry->port = port; > >@@ -776,7 +776,7 @@ TRACE_EVENT(i915_gem_request_wait_begin, > > TP_fast_assign( > > __entry->dev = req->i915->drm.primary->index; > > __entry->ring = req->engine->id; > >- __entry->ctx = req->ctx->hw_id; > >+ __entry->ctx = req->fence.context; > > __entry->seqno = req->fence.seqno; > > __entry->global = req->global_seqno; > > __entry->flags = flags; > > > > Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > > req->engine is fine? No chance of request re-use in the window? We still hold a reference on the rq, so we don't need to play rcu games to acquire a stable rq for the tracepoint. We only need to worry about objects whose lifetime is coupled to rq retirement. engine/i915 outlive all requests. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
