diff --git a/libc/malloc_debug/tests/malloc_debug_unit_tests.cpp b/libc/malloc_debug/tests/malloc_debug_unit_tests.cpp
index cd6d2c28e..2d6346fea 100644
--- a/libc/malloc_debug/tests/malloc_debug_unit_tests.cpp
+++ b/libc/malloc_debug/tests/malloc_debug_unit_tests.cpp
@@ -1463,7 +1463,7 @@ TEST_F(MallocDebugTest, backtrace_full_dump_on_exit) {
     BacktraceUnwindFake(
       std::vector<unwindstack::LocalFrameData>{{nullptr, 0x1100, 0x100, "fake1", 10},
                                                {nullptr, 0x1200, 0x200, "fake2", 20}});
-    unwindstack::MapInfo map_info{0x10000, 0x20000, 0, PROT_READ | PROT_EXEC, "/data/fake.so"};
+    unwindstack::MapInfo map_info{nullptr, 0x10000, 0x20000, 0, PROT_READ | PROT_EXEC, "/data/fake.so"};
     BacktraceUnwindFake(
       std::vector<unwindstack::LocalFrameData>{{&map_info, 0x1a000, 0xa000, "level1", 0},
                                                {&map_info, 0x1b000, 0xb000, "level2", 10}});