From 8deab3c165fab198141857c815ccf585eb8d1cf1 Mon Sep 17 00:00:00 2001
From: Douglas Katzman <dougk@google.com>
Date: Fri, 4 Aug 2017 08:56:51 -0400
Subject: [PATCH] Workaround spurious complaints by ASAN and MSAN.

ASAN says that gencgc reads wild pointers to the stack. Obviously.
---
 src/runtime/gencgc.c   | 8 +++++++-
 src/runtime/linux-os.c | 7 ++++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/runtime/gencgc.c b/src/runtime/gencgc.c
index 20c3364a4..ea7f8fe5f 100644
--- a/src/runtime/gencgc.c
+++ b/src/runtime/gencgc.c
@@ -3168,9 +3168,15 @@ move_pinned_pages_to_newspace()
     }
 }
 
+#if defined(__GNUC__) && defined(ADDRESS_SANITIZER)
+#define NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address))
+#else
+#define NO_SANITIZE_ADDRESS
+#endif
+
 /* Garbage collect a generation. If raise is 0 then the remains of the
  * generation are not raised to the next generation. */
-static void
+static void NO_SANITIZE_ADDRESS
 garbage_collect_generation(generation_index_t generation, int raise)
 {
     page_index_t i;
diff --git a/src/runtime/linux-os.c b/src/runtime/linux-os.c
index 53531def8..e3307cd2a 100644
--- a/src/runtime/linux-os.c
+++ b/src/runtime/linux-os.c
@@ -442,7 +442,12 @@ os_install_interrupt_handlers(void)
 char *
 os_get_runtime_executable_path(int external)
 {
-    char path[PATH_MAX + 1];
+    /* XXX: zero-init here is due to an apparent false positive with MSAN.
+       Everyone who's looked at this agrees that readlink() null-terminates
+       the array, or else it's not read at all if readlink() fails.
+       The sanitizer complaint actually occurs in copied_string().
+       It says "WARNING: MemorySanitizer: use-of-uninitialized-value" */
+    char path[PATH_MAX + 1] = {0};
     int size;
 
     size = readlink("/proc/self/exe", path, sizeof(path)-1);
-- 
2.11.4.GIT