[compiler-rt] r227803 - [ASan/Win] Add some diagnostics to help investigate Mprotect failures

[Timur Iskhodzhanov]

Author: timurrrr
Date: Mon Feb  2 09:04:23 2015
New Revision: 227803

URL: http://llvm.org/viewvc/llvm-project?rev=227803&view=rev
Log:
[ASan/Win] Add some diagnostics to help investigate Mprotect failures

Modified:
    compiler-rt/trunk/lib/asan/asan_rtl.cc
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_win.cc

Modified: compiler-rt/trunk/lib/asan/asan_rtl.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_rtl.cc?rev=227803&r1=227802&r2=227803&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/asan_rtl.cc (original)
+++ compiler-rt/trunk/lib/asan/asan_rtl.cc Mon Feb  2 09:04:23 2015
@@ -245,7 +245,13 @@ static void InitializeHighMemEnd() {
 }
 
 static void ProtectGap(uptr a, uptr size) {
-  CHECK_EQ(a, (uptr)Mprotect(a, size));
+  void *res = Mprotect(a, size);
+  if (a == (uptr)res)
+    return;
+  Report("ERROR: Failed to protect the shadow gap. "
+         "ASan cannot proceed correctly. ABORTING.\n");
+  DumpProcessMap();
+  Die();
 }
 
 static void PrintAddressSpaceLayout() {

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_win.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_win.cc?rev=227803&r1=227802&r2=227803&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_win.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_win.cc Mon Feb  2 09:04:23 2015
@@ -123,8 +123,13 @@ void *MmapNoReserveOrDie(uptr size, cons
 }
 
 void *Mprotect(uptr fixed_addr, uptr size) {
-  return VirtualAlloc((LPVOID)fixed_addr, size,
-                      MEM_RESERVE | MEM_COMMIT, PAGE_NOACCESS);
+  void *res = VirtualAlloc((LPVOID)fixed_addr, size,
+                           MEM_RESERVE | MEM_COMMIT, PAGE_NOACCESS);
+  if (res == 0)
+    Report("WARNING: %s failed to "
+           "mprotect %p (%zd) bytes at %p (error code: %d)\n",
+           SanitizerToolName, size, size, fixed_addr, GetLastError());
+  return res;
 }
 
 void FlushUnneededShadowMemory(uptr addr, uptr size) {
@@ -139,7 +144,7 @@ void NoHugePagesInRegion(uptr addr, uptr
 bool MemoryRangeIsAvailable(uptr range_start, uptr range_end) {
   MEMORY_BASIC_INFORMATION mbi;
   CHECK(VirtualQuery((void *)range_start, &mbi, sizeof(mbi)));
-  return mbi.Protect & PAGE_NOACCESS &&
+  return mbi.Protect == PAGE_NOACCESS &&
          (uptr)mbi.BaseAddress + mbi.RegionSize >= range_end;
 }