diff --git a/include/private/gcconfig.h b/include/private/gcconfig.h
index ffbdc142..4a4350af 100644
--- a/include/private/gcconfig.h
+++ b/include/private/gcconfig.h
@@ -2895,7 +2895,8 @@
 # define NO_SA_SIGACTION
 #endif
 
-#if defined(NO_SA_SIGACTION) && defined(MPROTECT_VDB) && !defined(DARWIN) \
+#if (defined(NO_SA_SIGACTION) || defined(GC_NO_SIGSETJMP)) \
+    && defined(MPROTECT_VDB) && !defined(DARWIN) \
     && !defined(MSWIN32) && !defined(MSWINCE)
 # undef MPROTECT_VDB
 #endif
diff --git a/os_dep.c b/os_dep.c
index d3429d04..c9b51528 100644
--- a/os_dep.c
+++ b/os_dep.c
@@ -424,20 +424,38 @@ GC_INNER char * GC_get_maps(void)
   {
     ptr_t data_end = DATAEND;
 
-#   if (defined(LINUX) || defined(HURD)) && !defined(IGNORE_PROG_DATA_START)
+#   if defined(PLATFORM_ANDROID) && (defined(LINUX) || defined(HURD)) && !defined(IGNORE_PROG_DATA_START)
+      /* Workaround for "gold" (default) linker (as of Android NDK r10e). */
       /* Try the easy approaches first: */
-#     ifdef PLATFORM_ANDROID
-        /* Workaround for "gold" (default) linker (as of Android NDK r10e). */
-        if ((word)__data_start < (word)_etext
-            && (word)_etext < (word)__dso_handle) {
-          GC_data_start = (ptr_t)(__dso_handle);
-#         ifdef DEBUG_ADD_DEL_ROOTS
-            GC_log_printf(
-                "__data_start is wrong; using __dso_handle as data start\n");
-#         endif
-        } else
+      if ((word)__data_start < (word)_etext
+          && (word)_etext < (word)__dso_handle) {
+        GC_data_start = (ptr_t)(__dso_handle);
+#       ifdef DEBUG_ADD_DEL_ROOTS
+          GC_log_printf(
+              "__data_start is wrong; using __dso_handle as data start\n");
+#       endif
+      } else if (COVERT_DATAFLOW(__data_start) != 0) {
+        GC_data_start = (ptr_t)(__data_start);
+      } else {
+        GC_data_start = (ptr_t)(data_start);
+      }
+      if (COVERT_DATAFLOW(GC_data_start) != 0) {
+        if ((word)GC_data_start > (word)data_end)
+          ABORT_ARG2("Wrong __data_start/_end pair",
+                     ": %p .. %p", (void *)GC_data_start, (void *)data_end);
+        return;
+      }
+#     ifdef DEBUG_ADD_DEL_ROOTS
+        GC_log_printf("__data_start not provided\n");
 #     endif
-      /* else */ if (COVERT_DATAFLOW(__data_start) != 0) {
+#   elif !defined(PLATFORM_ANDROID) && (defined(LINUX) || defined(HURD)) && defined(USE_PROG_DATA_START)
+      /* Try the easy approaches first: */
+      /* However, this may lead to wrong data start value if libgc  */
+      /* code is put into a shared library (directly or indirectly) */
+      /* which is linked with -Bsymbolic-functions option.  Thus,   */
+      /* the following is not used by default.                      */
+
+      if (COVERT_DATAFLOW(__data_start) != 0) {
         GC_data_start = (ptr_t)(__data_start);
       } else {
         GC_data_start = (ptr_t)(data_start);
@@ -967,6 +985,7 @@ GC_INNER size_t GC_page_size = 0;
     /* the smallest location q s.t. [q,p) is addressable (!up). */
     /* We assume that p (up) or p-1 (!up) is addressable.       */
     /* Requires allocation lock.                                */
+    GC_ATTR_NO_SANITIZE_ADDR
     STATIC ptr_t GC_find_limit_with_bound(ptr_t p, GC_bool up, ptr_t bound)
     {
         static volatile ptr_t result;