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Changing check > order prevents dereferncing it in intel_engine_is_virtual(rq->engine). > Full description of possible scenarios at the inline comment before > the change. I came to the same conclusion but Chris mentioned "you create a guc virtual engine with just one bit in execution_mask" :) Suggestion from Chris was to have "guc virtual bit" in there or "eliminate the single engine guc virtuals". Regards, Nirmoy > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/7926 > Signed-off-by: Andrzej Hajda > --- > drivers/gpu/drm/i915/i915_request.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c > index 630a732aaecca8..8775952f5c1bbd 100644 > --- a/drivers/gpu/drm/i915/i915_request.c > +++ b/drivers/gpu/drm/i915/i915_request.c > @@ -166,8 +166,8 @@ static void i915_fence_release(struct dma_fence *fence) > * know that if the rq->execution_mask is a single bit, rq->engine > * can be a physical engine with the exact corresponding mask. > */ > - if (!intel_engine_is_virtual(rq->engine) && > - is_power_of_2(rq->execution_mask) && > + if (is_power_of_2(rq->execution_mask) && > + !intel_engine_is_virtual(rq->engine) && > !cmpxchg(&rq->engine->request_pool, NULL, rq)) > return; >