If two nop's (requests in-flight following a wedged device) complete at
the same time, the global_seqno value written to the HWSP is undefined
as the two threads are not serialized.
v2: Use irqsafe spinlock. We expect the callback may be called from
inside another irq spinlock, so we can't unconditionally restore irqs.
Fixes: ce1135c7de64 ("drm/i915: Complete requests in nop_submit_request")
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> #v1
---
drivers/gpu/drm/i915/i915_gem.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index ab8c6946fea4..6a6974ed8f74 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3014,10 +3014,15 @@ void i915_gem_reset_finish(struct drm_i915_private *dev_priv)
static void nop_submit_request(struct drm_i915_gem_request *request)
{
+ unsigned long flags;
+
GEM_BUG_ON(!i915_terminally_wedged(&request->i915->gpu_error));
dma_fence_set_error(&request->fence, -EIO);
- i915_gem_request_submit(request);
+
+ spin_lock_irqsave(&request->engine->timeline->lock, flags);
+ __i915_gem_request_submit(request);
intel_engine_init_global_seqno(request->engine, request->global_seqno);
+ spin_unlock_irqrestore(&request->engine->timeline->lock, flags);
}
static void engine_set_wedged(struct intel_engine_cs *engine)
--
2.14.2
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