[llvm] [Support] Don't take a lock in CrashRecoverySignalHandler (PR #219529)

[Oliver Hunt via llvm-commits]

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@@ -369,8 +369,12 @@ static void CrashRecoverySignalHandler(int Signal) {
     // that the enclosing application will terminate soon, and we won't want to
     // attempt crash recovery again.
     //
-    // This call of Disable isn't thread safe, but it doesn't actually matter.
-    CrashRecoveryContext::Disable();
+    // Uninstall directly rather than through Disable(): a signal handler must
+    // not take a lock, and a lock with static storage duration may already be
+    // destroyed by the time a signal is delivered during exit(). Racing with
+    // another thread here doesn't matter.
+    gCrashRecoveryEnabled = false;
+    uninstallExceptionOrSignalHandlers();
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ojhunt wrote:

Waiting for a future PR saying that racing does matter :D :D :D 

https://github.com/llvm/llvm-project/pull/219529