<div dir="ltr">Thanks! </div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Feb 21, 2013 at 12:29 AM, Reid Kleckner <span dir="ltr"><<a href="mailto:reid@kleckner.net" target="_blank">reid@kleckner.net</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: rnk<br>
Date: Wed Feb 20 14:29:48 2013<br>
New Revision: 175661<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=175661&view=rev" target="_blank">http://llvm.org/viewvc/llvm-project?rev=175661&view=rev</a><br>
Log:<br>
[Sanitizer] Try to fix infinite loop in frame pointer unwinder<br>
<br>
Using > instead of >= ensures that each frame deref makes progress and<br>
that we eventually terminate.<br>
<br>
Issue: <a href="https://code.google.com/p/address-sanitizer/issues/detail?id=162" target="_blank">https://code.google.com/p/address-sanitizer/issues/detail?id=162</a><br>
<br>
Modified:<br>
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc<br>
<br>
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc?rev=175661&r1=175660&r2=175661&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc?rev=175661&r1=175660&r2=175661&view=diff</a><br>

==============================================================================<br>
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc (original)<br>
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc Wed Feb 20 14:29:48 2013<br>
@@ -131,8 +131,9 @@ void StackTrace::FastUnwindStack(uptr pc<br>
   CHECK(size == 0 && trace[0] == pc);<br>
   size = 1;<br>
   uhwptr *frame = (uhwptr *)bp;<br>
-  uhwptr *prev_frame = frame;<br>
-  while (frame >= prev_frame &&<br>
+  uhwptr *prev_frame = frame - 1;<br>
+  // Avoid infinite loop when frame == frame[0] by using frame > prev_frame.<br>
+  while (frame > prev_frame &&<br>
          frame < (uhwptr *)stack_top - 2 &&<br>
          frame > (uhwptr *)stack_bottom &&<br>
          size < max_size) {<br>
<br>
<br>
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</blockquote></div><br></div>