diff --git a/compiler-rt/lib/lsan/CMakeLists.txt b/compiler-rt/lib/lsan/CMakeLists.txt
--- a/compiler-rt/lib/lsan/CMakeLists.txt
+++ b/compiler-rt/lib/lsan/CMakeLists.txt
@@ -3,6 +3,21 @@
 set(LSAN_CFLAGS ${SANITIZER_COMMON_CFLAGS})
 append_rtti_flag(OFF LSAN_CFLAGS)
 
+# When lsan scans the stack for detecting reachable pointers, it's possible for
+# a leaked pointer, which was pushed to the stack on an earlier function call,
+# to still exist on the stack when doing a leak check if that part of the stack
+# was not overwritten. In particular, if there's any uninitialized data in the
+# lsan runtime, and the SP we start from is sufficiently deep into the runtime,
+# then a leaked pointer could be marked as reachable. Such instances could be
+# mitigated by clobbering any uninitialized data.
+#
+# Keep as =zero to mitigate any performance costs as opposed to =pattern.
+#
+# Note that, in the general case, this may hide some bugs in lsan runtime
+# itself that would involve reading uninitialized memory.
+check_cxx_compiler_flag(-ftrivial-auto-var-init=zero COMPILER_RT_HAS_AUTO_VAR_INIT_ZERO)
+append_list_if(COMPILER_RT_HAS_AUTO_VAR_INIT_ZERO -ftrivial-auto-var-init=zero LSAN_CFLAGS)
+
 # Too many existing bugs, needs cleanup.
 append_list_if(COMPILER_RT_HAS_WNO_FORMAT -Wno-format LSAN_CFLAGS)