[scudo] Lock FallbackTSD before draining it am: 76dac14491

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/scudo/+/23184464

Change-Id: Ic9a39eb1692a36fec5ca5f3871bb8707d3f3f431
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

standalone/tsd_exclusive.h

diff --git a/standalone/tsd_exclusive.h b/standalone/tsd_exclusive.h
index 9d03773..2383674 100644
--- a/standalone/tsd_exclusive.h
+++ b/standalone/tsd_exclusive.h
@@ -63,7 +63,9 @@
     // We don't have a way to iterate all thread local `ThreadTSD`s. Simply
     // drain the `ThreadTSD` of current thread and `FallbackTSD`.
     Instance->drainCache(&ThreadTSD);
+    FallbackTSD.lock();
     Instance->drainCache(&FallbackTSD);
+    FallbackTSD.unlock();
   }
 
   ALWAYS_INLINE void initThreadMaybe(Allocator *Instance, bool MinimalInit) {