diff --git a/libc/bionic/pthread_internal.cpp b/libc/bionic/pthread_internal.cpp
index 51430e7..cda52aa 100644
--- a/libc/bionic/pthread_internal.cpp
+++ b/libc/bionic/pthread_internal.cpp
@@ -110,7 +110,7 @@
 
   // Historically we'd return null, but
   if (bionic_get_application_target_sdk_version() >= __ANDROID_API_O__) {
-    __libc_fatal("attempt to use invalid pthread_t");
+    __libc_fatal("invalid pthread_t %p passed to libc", thread);
   }
   return nullptr;
 }