Lands http://codereview.chromium.org/99349 for Ryan....

base/debug_util_posix.cc

 // Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "build/build_config.h"
 #include "base/debug_util.h"
 
 #include <errno.h>
 #include <execinfo.h>
 #include <fcntl.h>
@@ skipping 90 matching lines @@
 
   // Our pid is 0 without a debugger, assume this for any pid starting with 0.
   pid_index += tracer.size();
   return pid_index < status.size() && status[pid_index] != '0';
 }
 
 #endif  // OS_LINUX
 
 // static
 void DebugUtil::BreakDebugger() {
+#if !defined(ARCH_CPU_ARM_FAMILY)
   asm ("int3");
+#endif
 }
 
 StackTrace::StackTrace() {
   const int kMaxCallers = 256;
 
   void* callers[kMaxCallers];
   int count = backtrace(callers, kMaxCallers);
 
   // Though the backtrace API man page does not list any possible negative
   // return values, we still still exclude them because they would break the
@@ skipping 23 matching lines @@
     for (size_t i = 0; i < trace_.size(); ++i) {
       (*os) << "\t" << trace_[i] << "\n";
     }
   } else {
     (*os) << "Backtrace:\n";
     for (size_t i = 0; i < trace_.size(); ++i) {
       (*os) << "\t" << trace_symbols.get()[i] << "\n";
     }
   }
 }