[PATCH] D48668: [TSan] More detailed error message on failed sahdow memory madvise

[Aleksey Shlyapnikov via Phabricator via llvm-commits]

alekseyshl created this revision.
alekseyshl added a reviewer: eugenis.
Herald added subscribers: Sanitizers, delcypher, kubamracek.

Report errno value on failed shadow memory madvise attempt and add a
hint message with the possible workaround.


Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D48668

Files:
  lib/tsan/rtl/tsan_platform_posix.cc


Index: lib/tsan/rtl/tsan_platform_posix.cc
===================================================================
--- lib/tsan/rtl/tsan_platform_posix.cc
+++ lib/tsan/rtl/tsan_platform_posix.cc
@@ -16,30 +16,37 @@
 #if SANITIZER_POSIX
 
 #include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_errno.h"
 #include "sanitizer_common/sanitizer_libc.h"
 #include "sanitizer_common/sanitizer_procmaps.h"
 #include "tsan_platform.h"
 #include "tsan_rtl.h"
 
 namespace __tsan {
 
 static const char kShadowMemoryMappingWarning[] =
-    "FATAL: %s can not madvise shadow region [%zx, %zx] with %s\n";
+    "FATAL: %s can not madvise shadow region [%zx, %zx] with %s (errno: %d)\n";
+static const char kShadowMemoryMappingHint[] =
+    "HINT: if %s is not supported in your environment, you may set "
+    "TSAN_OPTIONS=%s=0\n";
 
 static void NoHugePagesInShadow(uptr addr, uptr size) {
   if (common_flags()->no_huge_pages_for_shadow)
     if (!NoHugePagesInRegion(addr, size)) {
       Printf(kShadowMemoryMappingWarning, SanitizerToolName, addr, addr + size,
-             "MADV_NOHUGEPAGE");
+             "MADV_NOHUGEPAGE", errno);
+      Printf(kShadowMemoryMappingHint, "MADV_NOHUGEPAGE",
+             "no_huge_pages_for_shadow");
       Die();
     }
 }
 
 static void DontDumpShadow(uptr addr, uptr size) {
   if (common_flags()->use_madv_dontdump)
     if (!DontDumpShadowMemory(addr, size)) {
       Printf(kShadowMemoryMappingWarning, SanitizerToolName, addr, addr + size,
-             "MADV_DONTDUMP");
+             "MADV_DONTDUMP", errno);
+      Printf(kShadowMemoryMappingHint, "MADV_DONTDUMP", "use_madv_dontdump");
       Die();
     }
 }


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