Check stack pointer to be inside stack when unwinding.

base/debug/stack_trace.h

Index: base/debug/stack_trace.h
diff --git a/base/debug/stack_trace.h b/base/debug/stack_trace.h
index 23e7b5164b63472409a92e992c5c1095dfa48d26..749b5ee4785cccb0fc09b89f1cfca8bf16b7c55f 100644
--- a/base/debug/stack_trace.h
+++ b/base/debug/stack_trace.h
@@ -102,6 +102,14 @@ class BASE_EXPORT StackTrace {
 };
 
 #if HAVE_TRACE_STACK_FRAME_POINTERS
+
+// Used by TraceStackFramePointers() to store info about the stack.
+struct BASE_EXPORT PerThreadStackInfo {

[Primiano Tucci (use gerrit), 2016/05/31 16:13:07]

maybe s/PerThreadStackInfo/ThreadStackLimits/

[Dmitry Skiba, 2016/05/31 21:52:18]

Acknowledged.

+  PerThreadStackInfo();
+  uintptr_t start_address;
+  bool start_address_final;
+};
+
 // Traces the stack by using frame pointers. This function is faster but less
 // reliable than StackTrace. It should work for debug and profiling builds,
 // but not for release builds (although there are some exceptions).
@@ -110,9 +118,21 @@ class BASE_EXPORT StackTrace {
 // after skipping |skip_initial| frames. Note that the function itself is not
 // added to the trace so |skip_initial| should be 0 in most cases.
 // Returns number of frames written.
-BASE_EXPORT size_t TraceStackFramePointers(const void** out_trace,
-                                           size_t max_depth,
-                                           size_t skip_initial);
+//
+// Note on |stack_info|. By default the function relies on heuristics to check

[Primiano Tucci (use gerrit), 2016/05/31 16:13:07]

IMHO this comment is a bit too apologetic. I'd just say:
|stack_info| is an optional cache that avoids recomputing the stack limits on
each invocation. The caller is supposed to just keep it in a TLS and pass it
back.

[Dmitry Skiba, 2016/05/31 21:52:18]

Hmm, I don't see it that way. I think it explains motivation behind stack_info,
which can help deciding whether or not need you need it.

+// whether a stack pointer is within the stack before dereferencing it. That
+// works, but is not very reliable. Proper way to check that is to ask the OS
+// for the stack info, but that is costly thing to do on each call.
+// This is what |stack_info| is for - it provides a place where function
+// caches info about the stack. Put it in your per-thread data structure, pass
+// into the function, and voila - stack pointers are properly checked without
+// any runtime overhead.
+BASE_EXPORT size_t TraceStackFramePointers(
+    const void** out_trace,
+    size_t max_depth,
+    size_t skip_initial,
+    PerThreadStackInfo* stack_info = nullptr);
+
 #endif  // HAVE_TRACE_STACK_FRAME_POINTERS
 
 namespace internal {