commit a9e144df0751ae935c3ff40cd20ad7965fea72b5
author Florian Mayer <fmayer@google.com> Mon Nov 11 13:39:05 2024 -0800
committer Florian Mayer <fmayer@google.com> Tue Nov 12 12:16:55 2024 -0800
tree 727b827ecafdccb55b4368034f62c0ddaf8afc87
parent 756e765fa408c6aedb1f6cbe95645ffed6874909

[MTE] Cleanup stack buffer for detached threads

Bug: 378140560
Bug: 377483468
Change-Id: Ie20b7204894c03d4e3ddb10a3f1f9017c4909e38

libc/bionic/pthread_exit.cpp

diff --git a/libc/bionic/pthread_exit.cpp b/libc/bionic/pthread_exit.cpp
index 0181aba..27d05c2 100644
--- a/libc/bionic/pthread_exit.cpp
+++ b/libc/bionic/pthread_exit.cpp
@@ -33,10 +33,11 @@
 #include <string.h>
 #include <sys/mman.h>
 
-#include "private/bionic_constants.h"
-#include "private/bionic_defs.h"
+#include "platform/bionic/mte.h"
 #include "private/ScopedRWLock.h"
 #include "private/ScopedSignalBlocker.h"
+#include "private/bionic_constants.h"
+#include "private/bionic_defs.h"
 #include "pthread_internal.h"
 
 extern "C" __noreturn void _exit_with_stack_teardown(void*, size_t);
@@ -67,7 +68,7 @@
 }
 
 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
-void pthread_exit(void* return_value) {
+__attribute__((no_sanitize("memtag"))) void pthread_exit(void* return_value) {
   // Call dtors for thread_local objects first.
   __cxa_thread_finalize();
 
@@ -138,6 +139,13 @@
   __notify_thread_exit_callbacks();
   __hwasan_thread_exit();
 
+#if defined(__aarch64__)
+  if (void* stack_mte_tls = thread->bionic_tcb->tls_slot(TLS_SLOT_STACK_MTE)) {
+    stack_mte_free_ringbuffer(reinterpret_cast<uintptr_t>(stack_mte_tls));
+  }
+#endif
+  // Everything below this line needs to be no_sanitize("memtag").
+
   if (old_state == THREAD_DETACHED && thread->mmap_size != 0) {
     // We need to free mapped space for detached threads when they exit.
     // That's not something we can do in C.