From d8282a0da137a1e503b1c89febdbe766a55b750a Mon Sep 17 00:00:00 2001
From: Valentin Gosu <valentin.gosu@gmail.com>
Date: Fri, 6 Dec 2019 13:01:55 +0100
Subject: Use mutex in PACResolver when accessing mRequest from multiple
 threads.

---
 netwerk/base/ProxyAutoConfig.cpp | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

(limited to 'netwerk')

diff --git a/netwerk/base/ProxyAutoConfig.cpp b/netwerk/base/ProxyAutoConfig.cpp
index 4d7a6c1fd..6a9577669 100644
--- a/netwerk/base/ProxyAutoConfig.cpp
+++ b/netwerk/base/ProxyAutoConfig.cpp
@@ -271,6 +271,7 @@ public:
 
   PACResolver()
     : mStatus(NS_ERROR_FAILURE)
+    , mMutex("PACResolver::Mutex")
   {
   }
 
@@ -279,9 +280,15 @@ public:
                               nsIDNSRecord *record,
                               nsresult status) override
   {
-    if (mTimer) {
-      mTimer->Cancel();
-      mTimer = nullptr;
+    nsCOMPtr<nsITimer> timer;
+    {
+      MutexAutoLock lock(mMutex);
+      timer.swap(mTimer);
+      mRequest = nullptr;
+    }
+    
+    if (timer) {
+      timer->Cancel();
     }
 
     mRequest = nullptr;
@@ -293,9 +300,15 @@ public:
   // nsITimerCallback
   NS_IMETHOD Notify(nsITimer *timer) override
   {
-    if (mRequest)
-      mRequest->Cancel(NS_ERROR_NET_TIMEOUT);
-    mTimer = nullptr;
+    nsCOMPtr<nsICancelable> request;
+    {
+      MutexAutoLock lock(mMutex);
+      request.swap(mRequest);
+      mTimer = nullptr;
+    }
+    if (request) {
+      request->Cancel(NS_ERROR_NET_TIMEOUT);
+    }
     return NS_OK;
   }
 
@@ -303,6 +316,7 @@ public:
   nsCOMPtr<nsICancelable> mRequest;
   nsCOMPtr<nsIDNSRecord>  mResponse;
   nsCOMPtr<nsITimer>      mTimer;
+  Mutex                   mMutex;
 
 private:
   ~PACResolver() {}
-- 
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