diff --git a/compiler-rt/lib/asan/asan_allocator.cpp b/compiler-rt/lib/asan/asan_allocator.cpp
--- a/compiler-rt/lib/asan/asan_allocator.cpp
+++ b/compiler-rt/lib/asan/asan_allocator.cpp
@@ -1124,6 +1124,15 @@
   return 0;
 }
 
+void ForEachRegisteredThreadContextCb(ThreadContextBase *tctx, void *arg) {
+  // This function can be used to treat memory reachable from `tctx` as live.
+  // This is useful for threads that have been created but not yet started.
+
+  // This is currently a no-op because the ASan `pthread_create()` interceptor
+  // blocks until the child thread starts which keeps the thread's `arg` pointer
+  // live.
+}
+
 uptr GetUserBegin(uptr chunk) {
   __asan::AsanChunk *m = __asan::instance.GetAsanChunkByAddrFastLocked(chunk);
   return m ? m->Beg() : 0;
diff --git a/compiler-rt/lib/lsan/lsan_common.h b/compiler-rt/lib/lsan/lsan_common.h
--- a/compiler-rt/lib/lsan/lsan_common.h
+++ b/compiler-rt/lib/lsan/lsan_common.h
@@ -20,6 +20,7 @@
 #include "sanitizer_common/sanitizer_platform.h"
 #include "sanitizer_common/sanitizer_stoptheworld.h"
 #include "sanitizer_common/sanitizer_symbolizer.h"
+#include "sanitizer_common/sanitizer_thread_registry.h"
 
 // LeakSanitizer relies on some Glibc's internals (e.g. TLS machinery) on Linux.
 // Also, LSan doesn't like 32 bit architectures
@@ -142,6 +143,7 @@
 void ScanRootRegion(Frontier *frontier, RootRegion const &region,
                     uptr region_begin, uptr region_end, bool is_readable);
 void ForEachExtraStackRangeCb(uptr begin, uptr end, void* arg);
+void ForEachRegisteredThreadContextCb(ThreadContextBase *tctx, void *arg);
 // Run stoptheworld while holding any platform-specific locks, as well as the
 // allocator and thread registry locks.
 void LockStuffAndStopTheWorld(StopTheWorldCallback callback,
diff --git a/compiler-rt/lib/lsan/lsan_common.cpp b/compiler-rt/lib/lsan/lsan_common.cpp
--- a/compiler-rt/lib/lsan/lsan_common.cpp
+++ b/compiler-rt/lib/lsan/lsan_common.cpp
@@ -520,6 +520,11 @@
   ForEachChunk(MarkInvalidPCCb, &arg);
 }
 
+void ProcessThreadRegistry(Frontier *frontier) {
+  GetThreadRegistryLocked()->RunCallbackForEachThreadLocked(
+      ForEachRegisteredThreadContextCb, frontier);
+}
+
 // Sets the appropriate tag on each chunk.
 static void ClassifyAllChunks(SuspendedThreadsList const &suspended_threads,
                               Frontier *frontier) {
@@ -532,6 +537,7 @@
   ForEachChunk(CollectIgnoredCb, frontier);
   ProcessGlobalRegions(frontier);
   ProcessThreads(suspended_threads, frontier);
+  ProcessThreadRegistry(frontier);
   ProcessRootRegions(frontier);
   FloodFillTag(frontier, kReachable);
 
diff --git a/compiler-rt/lib/lsan/lsan_thread.cpp b/compiler-rt/lib/lsan/lsan_thread.cpp
--- a/compiler-rt/lib/lsan/lsan_thread.cpp
+++ b/compiler-rt/lib/lsan/lsan_thread.cpp
@@ -112,4 +112,13 @@
   return thread_registry;
 }
 
+void ForEachRegisteredThreadContextCb(ThreadContextBase *tctx, void *arg) {
+  // This function can be used to treat memory reachable from `tctx` as live.
+  // This is useful for threads that have been created but not yet started.
+
+  // This is currently a no-op because the LSan `pthread_create()` interceptor
+  // blocks until the child thread starts which keeps the thread's `arg` pointer
+  // live.
+}
+
 }  // namespace __lsan