1 files changed, 16 insertions, 2 deletions
diff --git a/widget/GfxInfoBase.cpp b/widget/GfxInfoBase.cpp
index c937f5099..e20de8277 100644
--- a/widget/GfxInfoBase.cpp
+++ b/widget/GfxInfoBase.cpp
@@ -43,6 +43,7 @@ using mozilla::MutexAutoLock;
 
 nsTArray<GfxDriverInfo>* GfxInfoBase::mDriverInfo;
 bool GfxInfoBase::mDriverInfoObserverInitialized;
+bool GfxInfoBase::mShutdownOccurred;
 
 // Observes for shutdown so that the child GfxDriverInfo list is freed.
 class ShutdownObserver : public nsIObserver
@@ -62,11 +63,17 @@ public:
     delete GfxInfoBase::mDriverInfo;
     GfxInfoBase::mDriverInfo = nullptr;
 
-    for (uint32_t i = 0; i < DeviceFamilyMax; i++)
+    for (uint32_t i = 0; i < DeviceFamilyMax; i++) {
       delete GfxDriverInfo::mDeviceFamilies[i];
+      GfxDriverInfo::mDeviceFamilies[i] = nullptr;
+    }
 
-    for (uint32_t i = 0; i < DeviceVendorMax; i++)
+    for (uint32_t i = 0; i < DeviceVendorMax; i++) {
       delete GfxDriverInfo::mDeviceVendors[i];
+      GfxDriverInfo::mDeviceVendors[i] = nullptr;
+    }
+
+    GfxInfoBase::mShutdownOccurred = true;
 
     return NS_OK;
   }
@@ -849,6 +856,13 @@ GfxInfoBase::GetFeatureStatusImpl(int32_t aFeature,
     return NS_OK;
   }
 
+  if (mShutdownOccurred) {
+    // This is futile; we've already commenced shutdown and our blocklists have
+    // been deleted. We may want to look into resurrecting the blocklist instead
+    // but for now, just don't even go there.
+    return NS_OK;
+  }
+
   // If an operating system was provided by the derived GetFeatureStatusImpl,
   // grab it here. Otherwise, the OS is unknown.
   OperatingSystem os = (aOS ? *aOS : OperatingSystem::Unknown);