Fix stack walking to notice if the frame is obviously not valid.

base/debug/stack_trace.cc

Index: base/debug/stack_trace.cc
diff --git a/base/debug/stack_trace.cc b/base/debug/stack_trace.cc
index 94ff7d0755ab50a650ebcee9dfbe05ab287972b2..83eb415ec1e0ee631af590e69d258f66d8693e99 100644
--- a/base/debug/stack_trace.cc
+++ b/base/debug/stack_trace.cc
@@ -111,12 +111,14 @@ bool IsStackFrameValid(uintptr_t fp, uintptr_t prev_fp, uintptr_t stack_end) {
   // Check alignment.
   if (fp & (sizeof(uintptr_t) - 1)) return false;
 
+  // A PC that is too small means we've gone off the end of the stack.
+  const uintptr_t kMinimumReasonablePC = 32768;
+  if (GetStackFramePC(fp) < kMinimumReasonablePC)
+    return false;
+
   if (stack_end) {
     // Both fp[0] and fp[1] must be within the stack.
     if (fp > stack_end - 2 * sizeof(uintptr_t)) return false;
-
-    // Additional check to filter out false positives.
-    if (GetStackFramePC(fp) < 32768) return false;
   }
 
   return true;