[PATCH] D14656: [sanitizer] Stop unwinding the stack when a close-to-zero PC is found

[Kuba Brecka via llvm-commits]

kubabrecka updated this revision to Diff 40267.
kubabrecka added a comment.

Adding the check into slow unwinder as well.


http://reviews.llvm.org/D14656

Files:
  lib/sanitizer_common/sanitizer_stacktrace.cc
  lib/sanitizer_common/sanitizer_unwind_linux_libcdep.cc

Index: lib/sanitizer_common/sanitizer_unwind_linux_libcdep.cc
===================================================================
--- lib/sanitizer_common/sanitizer_unwind_linux_libcdep.cc
+++ lib/sanitizer_common/sanitizer_unwind_linux_libcdep.cc
@@ -103,6 +103,8 @@
   UnwindTraceArg *arg = (UnwindTraceArg*)param;
   CHECK_LT(arg->stack->size, arg->max_depth);
   uptr pc = Unwind_GetIP(ctx);
+  const uptr kPageSize = GetPageSizeCached();
+  if (pc < kPageSize) return UNWIND_STOP;
   arg->stack->trace_buffer[arg->stack->size++] = pc;
   if (arg->stack->size == arg->max_depth) return UNWIND_STOP;
   return UNWIND_CONTINUE;
Index: lib/sanitizer_common/sanitizer_stacktrace.cc
===================================================================
--- lib/sanitizer_common/sanitizer_stacktrace.cc
+++ lib/sanitizer_common/sanitizer_stacktrace.cc
@@ -71,6 +71,7 @@
 
 void BufferedStackTrace::FastUnwindStack(uptr pc, uptr bp, uptr stack_top,
                                          uptr stack_bottom, u32 max_depth) {
+  const uptr kPageSize = GetPageSizeCached();
   CHECK_GE(max_depth, 2);
   trace_buffer[0] = pc;
   size = 1;
@@ -95,6 +96,8 @@
 #else
     uhwptr pc1 = frame[1];
 #endif
+    if (pc1 < kPageSize)
+      break;
     if (pc1 != pc) {
       trace_buffer[size++] = (uptr) pc1;
     }


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