malloc_debug: reset TrackData mutex after fork

Add a pthread_atfork handler to malloc_debug to lock the TrackData mutex
during fork and reset it in the child.  Ensures that the TrackData is
consistent when forking from a multi-threaded process, and that the
mutex is in a defined state in the child.

Change-Id: I0dfed30045a28551217ceac227d33b2e18894932

1 files changed, 18 insertions, 0 deletions

diff --git a/libc/malloc_debug/DebugData.cpp b/libc/malloc_debug/DebugData.cpp
index bf2a0f5e5..cf16c29ac 100644
--- a/libc/malloc_debug/DebugData.cpp
+++ b/libc/malloc_debug/DebugData.cpp
@@ -82,3 +82,21 @@ bool DebugData::Initialize() {
   }
   return true;
 }
+
+void DebugData::PrepareFork() {
+  if (track != nullptr) {
+    track->PrepareFork();
+  }
+}
+
+void DebugData::PostForkParent() {
+  if (track != nullptr) {
+    track->PostForkParent();
+  }
+}
+
+void DebugData::PostForkChild() {
+  if (track != nullptr) {
+    track->PostForkChild();
+  }
+}