Fix crash walking call stack on Linux.

runtime/vm/profiler.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include <cstdio>
 
 #include "platform/utils.h"
 
 #include "vm/atomic.h"
 #include "vm/isolate.h"
@@ skipping 115 matching lines @@
   if (profiler_data == NULL) {
     return;
   }
   SampleBuffer* sample_buffer = profiler_data->sample_buffer();
   if (sample_buffer == NULL) {
     return;
   }
   Sample* sample = sample_buffer->ReserveSample();
   sample->Init(Sample::kIsolateStart, isolate, OS::GetCurrentTimeMicros(),
                Thread::GetCurrentThreadId());
-  ThreadInterrupter::Register(ThreadInterruptNoOp, isolate);
+  ThreadInterrupter::Register(RecordSampleInterruptCallback, isolate);
 }
 
 
 void Profiler::EndExecution(Isolate* isolate) {
   if (isolate == NULL) {
     return;
   }
   if (!FLAG_profile) {
     return;
   }
@@ skipping 308 matching lines @@
     stack_upper_(stack_upper),
     original_pc_(pc),
     original_fp_(fp),
     original_sp_(sp),
     lower_bound_(stack_lower) {
   ASSERT(sample_ != NULL);
 }
 
 
 int ProfilerSampleStackWalker::walk() {
+  const intptr_t kMaxStep = 0x1000;  // 4K.
   uword* pc = reinterpret_cast<uword*>(original_pc_);
 #define WALK_STACK
 #if defined(WALK_STACK)
   uword* fp = reinterpret_cast<uword*>(original_fp_);
   uword* previous_fp = fp;
+  if (original_sp_ > original_fp_) {
+    // Stack pointer should not be above frame pointer.
+    return 0;
+  }
+  if ((original_fp_ - original_sp_) >= kMaxStep) {
+    // Gap between frame pointer and stack pointer is
+    // too large.
+    return 0;
+  }
   if (original_sp_ < lower_bound_) {
     // The stack pointer gives us a better lower bound than
     // the isolates stack limit.
     lower_bound_ = original_sp_;
   }
   int i = 0;
   for (; i < Sample::kNumStackFrames; i++) {
     sample_->pcs[i] = reinterpret_cast<uintptr_t>(pc);
     if (!ValidFramePointer(fp)) {
       break;
     }
     pc = CallerPC(fp);
     previous_fp = fp;
     fp = CallerFP(fp);
-    if ((fp <= previous_fp) || !ValidFramePointer(fp)) {
-      // Frame pointers should only move to higher addresses.
+    intptr_t step = fp - previous_fp;
+    if ((step >= kMaxStep) || (fp <= previous_fp) || !ValidFramePointer(fp)) {
+      // Frame pointer step is too large.
+      // Frame pointer did not move to a higher address.
+      // Frame pointer is outside of isolate stack bounds.
       break;
     }
     // Move the lower bound up.
     lower_bound_ = reinterpret_cast<uintptr_t>(fp);
   }
   return i;
 #else
   sample_->pcs[0] = reinterpret_cast<uintptr_t>(pc);
   return 0;
 #endif
@@ skipping 17 matching lines @@
     return false;
   }
   uintptr_t cursor = reinterpret_cast<uintptr_t>(fp);
   cursor += sizeof(fp);
   bool r = cursor >= lower_bound_ && cursor < stack_upper_;
   return r;
 }
 
 
 }  // namespace dart