[libc-commits] [PATCH] D76267: [libc] Resolve race condition in sub-process test runner.

[Paula Toth via Phabricator via libc-commits]

PaulkaToast updated this revision to Diff 250872.
PaulkaToast added a comment.

Add comment explaining why we wait on pid.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D76267/new/

https://reviews.llvm.org/D76267

Files:
  libc/utils/testutils/ExecuteFunctionUnix.cpp


Index: libc/utils/testutils/ExecuteFunctionUnix.cpp
===================================================================
--- libc/utils/testutils/ExecuteFunctionUnix.cpp
+++ libc/utils/testutils/ExecuteFunctionUnix.cpp
@@ -67,8 +67,12 @@
   }
 
   int WStatus = 0;
-  int status = ::waitpid(Pid, &WStatus, WNOHANG);
-  assert(status == Pid && "wait call should not block here");
+  // Wait on the pid of the subprocess here so it gets collected by the system
+  // and doesn't turn into a zombie.
+  pid_t status = ::waitpid(Pid, &WStatus, 0);
+  if (status == -1)
+    return ProcessStatus::Error("waitpid(2) failed");
+  assert(status == Pid);
   (void)status;
   return {WStatus};
 }


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