From bc2aa1f05cb439345b3f219dbb820e0762631e49 Mon Sep 17 00:00:00 2001
From: Moonchild <moonchild@palemoon.org>
Date: Wed, 9 Feb 2022 18:23:27 +0000
Subject: [PATCH] [DOM] Clear sinks and block further use after storage
 observer shutdown.

---
 dom/storage/DOMStorageIPC.cpp      | 6 ++++--
 dom/storage/DOMStorageObserver.cpp | 6 ++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/dom/storage/DOMStorageIPC.cpp b/dom/storage/DOMStorageIPC.cpp
index 442941a7a0..1cf3463459 100644
--- a/dom/storage/DOMStorageIPC.cpp
+++ b/dom/storage/DOMStorageIPC.cpp
@@ -213,8 +213,10 @@ DOMStorageDBChild::RecvObserve(const nsCString& aTopic,
                                const nsString& aOriginAttributesPattern,
                                const nsCString& aOriginScope)
 {
-  DOMStorageObserver::Self()->Notify(
-    aTopic.get(), aOriginAttributesPattern, aOriginScope);
+  DOMStorageObserver* observer = DOMStorageObserver::Self();
+  if (observer) {
+    observer->Notify(aTopic.get(), aOriginAttributesPattern, aOriginScope);
+  }
   return true;
 }
 
diff --git a/dom/storage/DOMStorageObserver.cpp b/dom/storage/DOMStorageObserver.cpp
index 295cee4ab0..9de18738da 100644
--- a/dom/storage/DOMStorageObserver.cpp
+++ b/dom/storage/DOMStorageObserver.cpp
@@ -90,6 +90,8 @@ DOMStorageObserver::Shutdown()
   if (!sSelf) {
     return NS_ERROR_NOT_INITIALIZED;
   }
+  
+  sSelf->mSinks.Clear();
 
   NS_RELEASE(sSelf);
   return NS_OK;
@@ -123,6 +125,10 @@ DOMStorageObserver::Observe(nsISupports* aSubject,
                             const char* aTopic,
                             const char16_t* aData)
 {
+  if (NS_WARN_IF(!sSelf)) {  // Shutdown took place, so bail.
+    return NS_OK;
+  }
+
   nsresult rv;
 
   // Start the thread that opens the database.