[PATCH] D61096: posix_spawn should retry upon EINTR

[JF Bastien via Phabricator via llvm-commits]

jfb created this revision.
jfb added reviewers: Bigcheese, arphaman.
Herald added subscribers: llvm-commits, kristina, dexonsmith, jkorous.
Herald added a project: LLVM.

We've seen cases of bots failing with:

  clang: error: unable to execute command: posix_spawn failed: Interrupted system call

Add a small retry loop to posix_spawn in case this happens. Don't retry too much in case there's some systemic problem going on, but retry a few times.
rdar://problem/50181448


Repository:
  rL LLVM

https://reviews.llvm.org/D61096

Files:
  lib/Support/Unix/Program.inc


Index: lib/Support/Unix/Program.inc
===================================================================
--- lib/Support/Unix/Program.inc
+++ lib/Support/Unix/Program.inc
@@ -245,12 +245,16 @@
       Envp = const_cast<const char **>(*_NSGetEnviron());
 #endif
 
-    // Explicitly initialized to prevent what appears to be a valgrind false
-    // positive.
-    pid_t PID = 0;
-    int Err = posix_spawn(&PID, Program.str().c_str(), FileActions,
-                          /*attrp*/ nullptr, const_cast<char **>(Argv),
-                          const_cast<char **>(Envp));
+    constexpr int maxRetries = 8;
+    int retries = 0;
+    pid_t PID;
+    int Err;
+    do {
+      PID = 0; // Make Valgrind happy.
+      Err = posix_spawn(&PID, Program.str().c_str(), FileActions,
+                        /*attrp*/ nullptr, const_cast<char **>(Argv),
+                        const_cast<char **>(Envp));
+    } while (Err == EINTR && ++retries < maxRetries);
 
     if (FileActions)
       posix_spawn_file_actions_destroy(FileActions);


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