commit 5d1c14f41bac357c730aa47d705c1f1da7625280
author Josh Gao <jmgao@google.com> Fri Apr 20 12:04:41 2018 -0700
committer Josh Gao <jmgao@google.com> Fri Apr 20 13:23:20 2018 -0700
tree 7e33631043e5fa3fb04a5bac82685b0e753eb56b
parent 2f37a15472945194fed528cb8d3104aa4865fc4c

libdebuggerd: clone registers before we Unwind with them.

Bug: http://b/77296294
Test: manual inspection of tombstone generated by crasher
Change-Id: I4b017701d7d2041db4aefbbb90977e99b844c328

debuggerd/libdebuggerd/tombstone.cpp

diff --git a/debuggerd/libdebuggerd/tombstone.cpp b/debuggerd/libdebuggerd/tombstone.cpp
index 55d6204..2b75292 100644
--- a/debuggerd/libdebuggerd/tombstone.cpp
+++ b/debuggerd/libdebuggerd/tombstone.cpp
@@ -422,8 +422,10 @@
 
   dump_registers(log, thread_info.registers.get());
 
+  // Unwind will mutate the registers, so make a copy first.
+  std::unique_ptr<Regs> regs_copy(thread_info.registers->Clone());
   std::vector<backtrace_frame_data_t> frames;
-  if (!Backtrace::Unwind(thread_info.registers.get(), map, &frames, 0, nullptr)) {
+  if (!Backtrace::Unwind(regs_copy.get(), map, &frames, 0, nullptr)) {
     _LOG(log, logtype::THREAD, "Failed to unwind");
     return false;
   }