1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 27fe5a9315f0..1051fdf37d20 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2719,7 +2719,16 @@ int i915_gem_reset_prepare(struct drm_i915_private *dev_priv)
         for_each_engine(engine, dev_priv, id) {
                 struct drm_i915_gem_request *request;
 
+                /* Prevent request submission to the hardware until we have
+                 * completed the reset in i915_gem_reset_finish(). If a request
+                 * is completed by one engine, it may then queue a request
+                 * to a second via its engine->irq_tasklet *just* as we are
+                 * calling engine->init_hw() and also writing the ELSP.
+                 * Turning off the engine->irq_tasklet until the reset is over
+                 * prevents the race.
+                 */
                 tasklet_kill(&engine->irq_tasklet);
+                tasklet_disable(&engine->irq_tasklet);
 
                 if (engine_stalled(engine)) {
                         request = i915_gem_find_active_request(engine);
@@ -2858,7 +2867,13 @@ void i915_gem_reset(struct drm_i915_private *dev_priv)
 
 void i915_gem_reset_finish(struct drm_i915_private *dev_priv)
 {
+        struct intel_engine_cs *engine;
+        enum intel_engine_id id;
+
         lockdep_assert_held(&dev_priv->drm.struct_mutex);
+
+        for_each_engine(engine, dev_priv, id)
+                tasklet_enable(&engine->irq_tasklet);
 }
 
 static void nop_submit_request(struct drm_i915_gem_request *request)