commit 69c4523cf45c7bbfea820f4beef21c336eed04fd
author Peter Collingbourne <pcc@google.com> Fri Apr 24 17:33:37 2020 -0700
committer Peter Collingbourne <pcc@google.com> Wed Apr 29 09:33:53 2020 -0700
tree 9d411faff722dd7128316ca9b967e371dcf87aea
parent 9f949625b93ee8b02ef419389823f276bfa0b418

Switch to new kernel ptrace interface for reading tags.

Bug: 135772972
Change-Id: I506429d7bff79f83828e1f0d5c0ea0468ee1580b

libunwindstack/MemoryMte.cpp

diff --git a/libunwindstack/MemoryMte.cpp b/libunwindstack/MemoryMte.cpp
index d1d0ebc..46a546e 100644
--- a/libunwindstack/MemoryMte.cpp
+++ b/libunwindstack/MemoryMte.cpp
@@ -17,6 +17,7 @@
 #if defined(ANDROID_EXPERIMENTAL_MTE)
 
 #include <sys/ptrace.h>
+#include <sys/uio.h>
 
 #include <bionic/mte.h>
 #include <bionic/mte_kernel.h>
@@ -28,7 +29,13 @@
 
 long MemoryRemote::ReadTag(uint64_t addr) {
 #if defined(__aarch64__)
-  return ptrace(PTRACE_PEEKTAG, pid_, (void*)addr, nullptr);
+  char tag;
+  iovec iov = {&tag, 1};
+  if (ptrace(PTRACE_PEEKMTETAGS, pid_, reinterpret_cast<void*>(addr), &iov) != 0 ||
+      iov.iov_len != 1) {
+    return -1;
+  }
+  return tag;
 #else
   (void)addr;
   return -1;