From a8fed672cbcc170436d1f90ac698d721fcc725b4 Mon Sep 17 00:00:00 2001
From: Valentin Gosu <valentin.gosu@gmail.com>
Date: Mon, 14 Sep 2020 09:27:42 +0000
Subject: [PATCH] Bug 1664020 - ShutdownEvent::PostAndWait should return
 immediately if posting the event fails r=necko-reviewers,kershaw

Differential Revision: https://phabricator.services.mozilla.com/D89648
---
 netwerk/cache2/CacheFileIOManager.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/netwerk/cache2/CacheFileIOManager.cpp b/netwerk/cache2/CacheFileIOManager.cpp
index 9dff05f13f91..5ffd12a9c071 100644
--- a/netwerk/cache2/CacheFileIOManager.cpp
+++ b/netwerk/cache2/CacheFileIOManager.cpp
@@ -544,12 +544,18 @@ class ShutdownEvent : public Runnable {
   void PostAndWait() {
     MonitorAutoLock mon(mMonitor);
 
-    DebugOnly<nsresult> rv;
-    rv = CacheFileIOManager::gInstance->mIOThread->Dispatch(
+    nsresult rv = CacheFileIOManager::gInstance->mIOThread->Dispatch(
         this,
         CacheIOThread::WRITE);  // When writes and closing of handles is done
     MOZ_ASSERT(NS_SUCCEEDED(rv));
 
+    // If we failed to post the even there's no reason to go into the loop
+    // because mNotified will never be set to true.
+    if (NS_FAILED(rv)) {
+      NS_WARNING("Posting ShutdownEvent task failed");
+      return;
+    }
+
     TimeDuration waitTime = TimeDuration::FromSeconds(1);
     while (!mNotified) {
       mon.Wait(waitTime);