Index: libc/src/stdlib/atexit.cpp
===================================================================
--- libc/src/stdlib/atexit.cpp
+++ libc/src/stdlib/atexit.cpp
@@ -27,8 +27,10 @@
 
 void call_exit_callbacks() {
   handler_list_mtx.lock();
-  for (auto callback : exit_callbacks) {
+  while (!exit_callbacks.empty()) {
     handler_list_mtx.unlock();
+    auto *callback = exit_callbacks.back();
+    exit_callbacks.pop_back();
     callback();
     handler_list_mtx.lock();
   }
Index: libc/test/src/stdlib/atexit_test.cpp
===================================================================
--- libc/test/src/stdlib/atexit_test.cpp
+++ libc/test/src/stdlib/atexit_test.cpp
@@ -78,17 +78,12 @@
   EXPECT_EXITS(test, 0);
 }
 
-// POSIX doesn't specify if an atexit handler can call atexit, it only says it
-// is undefined for a handler to call exit(3). The current implementation will
-// end up invoking the newly registered function, although glibc does, other
-// libc's do not. This just tests that we don't deadlock when an exit handler
-// calls atexit.
 TEST(LlvmLibcAtExit, HandlerCallsAtExit) {
   auto test = [] {
     __llvm_libc::atexit(+[] {
-      __llvm_libc::atexit(+[] { __builtin_trap(); });
-      __llvm_libc::exit(0);
+      __llvm_libc::atexit(+[] { __llvm_libc::exit(1); });
     });
+    __llvm_libc::exit(0);
   };
-  EXPECT_EXITS(test, 0);
+  EXPECT_EXITS(test, 1);
 }