diff --git a/docs/status.md b/docs/status.md
index 85f9b60..0cbcb47 100644
--- a/docs/status.md
+++ b/docs/status.md
@@ -49,6 +49,11 @@
   * `popen` now always uses `O_CLOEXEC`, not just with the `e` extension
   * Bug fixes to handling of UTF-8 U+fffe/U+ffff and code points above U+10ffff
   * `aligned_alloc` correctly verifies that `size` is a multiple of `alignment`
+  * Using `%n` with the printf family is now reported as a FORTIFY failure.
+    Previous versions of Android would ignore the `%n` but not consume the
+    corresponding pointer argument, leading to obscure errors. The scanf family
+    is unchanged.
+  * [fdsan](fdsan.md) detects common file descriptor errors at runtime.
 
 New libc functions in P (API level 28):
   * `aligned_alloc`
@@ -72,6 +77,10 @@
   * `%C` and `%S` support in the printf family (previously only the wprintf family supported these)
   * `%mc`/`%ms`/`%m[` support in the scanf family
   * `%s` support in strptime (strftime already supported it)
+  * Using a `pthread_mutex_t` after it's been destroyed will be detected at
+    runtime and reported as a FORTIFY failure.
+  * Passing a null `FILE*` or `DIR*` to libc is now detected at runtime and
+    reported as a FORTIFY failure.
 
 New libc functions in O (API level 26):
   * `sendto` FORTIFY support
@@ -96,6 +105,11 @@
   * `strtod_l`/`strtof_l`/`strtol_l`/`strtoul_l`
   * <wctype.h> `towctrans`/`towctrans_l`/`wctrans`/`wctrans_l`
 
+New libc behavior in O (API level 26):
+  * Passing an invalid `pthread_t` to libc is now detected at runtime and
+    reported as a FORTIFY failure. Most commonly this is a result of confusing
+    `pthread_t` and `pid_t`.
+
 New libc functions in N (API level 24):
   * more FORTIFY support functions (`fread`/`fwrite`/`getcwd`/`pwrite`/`write`)
   * all remaining `_FILE_OFFSET_BITS=64` functions, completing `_FILE_OFFSET_BITS=64` support in bionic (8)
@@ -108,6 +122,9 @@
   * GNU extensions `fileno_unlocked`/`strchrnul`
   * 32-bit `prlimit`
 
+New libc behavior in N (API level 24):
+  * `sem_wait` now returns EINTR when interrupted by a signal.
+
 New libc functions in M (API level 23):
   * <dirent.h> `telldir`, `seekdir`.
   * <malloc.h> `malloc_info`.
diff --git a/libc/include/android/fdsan.h b/libc/include/android/fdsan.h
index d71e6d4..1169ed0 100644
--- a/libc/include/android/fdsan.h
+++ b/libc/include/android/fdsan.h
@@ -149,19 +149,19 @@
  *
  * Returns 0 for untagged and invalid file descriptors.
  */
-uint64_t android_fdsan_get_owner_tag(int fd);
+uint64_t android_fdsan_get_owner_tag(int fd) __INTRODUCED_IN(29);
 
 /*
  * Get an owner tag's string representation.
  *
  * The return value points to memory with static lifetime, do not attempt to modify it.
  */
-const char* android_fdsan_get_tag_type(uint64_t tag);
+const char* android_fdsan_get_tag_type(uint64_t tag) __INTRODUCED_IN(29);
 
 /*
  * Get an owner tag's value, with the type masked off.
  */
-uint64_t android_fdsan_get_tag_value(uint64_t tag);
+uint64_t android_fdsan_get_tag_value(uint64_t tag) __INTRODUCED_IN(29);
 
 enum android_fdsan_error_level {
   // No errors.
diff --git a/libc/include/bits/get_device_api_level_inlines.h b/libc/include/bits/get_device_api_level_inlines.h
index 9c6e243..d14eb2c 100644
--- a/libc/include/bits/get_device_api_level_inlines.h
+++ b/libc/include/bits/get_device_api_level_inlines.h
@@ -28,11 +28,9 @@
 
 #pragma once
 
-#include <sys/cdefs.h>
+#if defined(__BIONIC_GET_DEVICE_API_LEVEL_INLINE)
 
-#if !defined(__BIONIC_GET_DEVICE_API_LEVEL_INLINE)
-#define __BIONIC_GET_DEVICE_API_LEVEL_INLINE static inline /* for versioner */
-#endif
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS
 
@@ -48,3 +46,5 @@
 }
 
 __END_DECLS
+
+#endif  // __BIONIC_GET_DEVICE_API_LEVEL_INLINE
diff --git a/libc/include/pthread.h b/libc/include/pthread.h
index 3089adc..724e5b7 100644
--- a/libc/include/pthread.h
+++ b/libc/include/pthread.h
@@ -137,7 +137,21 @@
                                         const struct timespec* __timeout) __INTRODUCED_IN_64(28);
 int pthread_cond_wait(pthread_cond_t* __cond, pthread_mutex_t* __mutex);
 
+#if defined(__clang__)
+/*
+ * Disable -Wbuiltin-requires-header because clang confuses this declaration with the one defined in
+ * "llvm/tools/clang/include/clang/Basic/Builtins.def", which did not define any formal arguments.
+ * It seems to be an upstream bug and the fix (https://reviews.llvm.org/D58531) is still under
+ * review. Thus, let's disable the warning for this function declaration.
+ */
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wbuiltin-requires-header"
+#endif
 int pthread_create(pthread_t* __pthread_ptr, pthread_attr_t const* __attr, void* (*__start_routine)(void*), void*);
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+
 int pthread_detach(pthread_t __pthread);
 void pthread_exit(void* __return_value) __noreturn;
 
diff --git a/libc/tzcode/bionic.cpp b/libc/tzcode/bionic.cpp
index 9051308..1742d79 100644
--- a/libc/tzcode/bionic.cpp
+++ b/libc/tzcode/bionic.cpp
@@ -228,13 +228,18 @@
   if (fd >= 0) return fd;
 #else
   // On the host, we don't expect those locations to exist, and we're not
-  // worried about security so we trust $ANDROID_DATA, $ANDROID_RUNTIME_ROOT
-  // and $ANDROID_ROOT to point us in the right direction.
+  // worried about security so we trust $ANDROID_DATA, $ANDROID_RUNTIME_ROOT,
+  // $ANDROID_TZDATA_ROOT, and $ANDROID_ROOT to point us in the right direction.
   char* path = make_path("ANDROID_DATA", "/misc/zoneinfo/current/tzdata");
   fd = __bionic_open_tzdata_path(path, olson_id, entry_length);
   free(path);
   if (fd >= 0) return fd;
 
+  path = make_path("ANDROID_TZDATA_ROOT", "/etc/tz/tzdata");
+  fd = __bionic_open_tzdata_path(path, olson_id, entry_length);
+  free(path);
+  if (fd >= 0) return fd;
+
   path = make_path("ANDROID_RUNTIME_ROOT", "/etc/tz/tzdata");
   fd = __bionic_open_tzdata_path(path, olson_id, entry_length);
   free(path);
diff --git a/linker/ld.config.format.md b/linker/ld.config.format.md
index 686d6be..faf5cc8 100644
--- a/linker/ld.config.format.md
+++ b/linker/ld.config.format.md
@@ -79,5 +79,8 @@
 # and links it to default namespace
 namespace.ns.links = default
 namespace.ns.link.default.shared_libs = libc.so:libdl.so:libm.so:libstdc++.so
+
+# This defines what libraries are allowed to be loaded from ns1
+namespace.ns1.whitelisted = libsomething.so
 ```
 
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 49c8f11..c60ab6a 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -4156,6 +4156,7 @@
     ns->set_isolated(ns_config->isolated());
     ns->set_default_library_paths(ns_config->search_paths());
     ns->set_permitted_paths(ns_config->permitted_paths());
+    ns->set_whitelisted_libs(ns_config->whitelisted_libs());
 
     namespaces[ns_config->name()] = ns;
     if (ns_config->visible()) {
diff --git a/linker/linker_config.cpp b/linker/linker_config.cpp
index f7f9c41..437aa86 100644
--- a/linker/linker_config.cpp
+++ b/linker/linker_config.cpp
@@ -552,6 +552,12 @@
     ns_config->set_isolated(properties.get_bool(property_name_prefix + ".isolated"));
     ns_config->set_visible(properties.get_bool(property_name_prefix + ".visible"));
 
+    std::string whitelisted =
+        properties.get_string(property_name_prefix + ".whitelisted", &lineno);
+    if (!whitelisted.empty()) {
+      ns_config->set_whitelisted_libs(android::base::Split(whitelisted, ":"));
+    }
+
     // these are affected by is_asan flag
     if (is_asan) {
       property_name_prefix += ".asan";
diff --git a/linker/linker_config.h b/linker/linker_config.h
index 49739ee..a318bba 100644
--- a/linker/linker_config.h
+++ b/linker/linker_config.h
@@ -92,6 +92,10 @@
     return permitted_paths_;
   }
 
+  const std::vector<std::string>& whitelisted_libs() const {
+    return whitelisted_libs_;
+  }
+
   const std::vector<NamespaceLinkConfig>& links() const {
     return namespace_links_;
   }
@@ -116,12 +120,17 @@
   void set_permitted_paths(std::vector<std::string>&& permitted_paths) {
     permitted_paths_ = permitted_paths;
   }
+
+  void set_whitelisted_libs(std::vector<std::string>&& whitelisted_libs) {
+    whitelisted_libs_ = whitelisted_libs;
+  }
  private:
   const std::string name_;
   bool isolated_;
   bool visible_;
   std::vector<std::string> search_paths_;
   std::vector<std::string> permitted_paths_;
+  std::vector<std::string> whitelisted_libs_;
   std::vector<NamespaceLinkConfig> namespace_links_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(NamespaceConfig);
diff --git a/linker/linker_config_test.cpp b/linker/linker_config_test.cpp
index 6a55bb2..4937056 100644
--- a/linker/linker_config_test.cpp
+++ b/linker/linker_config_test.cpp
@@ -56,6 +56,7 @@
   "enable.target.sdk.version = true\n"
   "additional.namespaces=system\n"
   "additional.namespaces+=vndk\n"
+  "additional.namespaces+=vndk_in_system\n"
   "namespace.default.isolated = true\n"
   "namespace.default.search.paths = /vendor/${LIB}\n"
   "namespace.default.permitted.paths = /vendor/${LIB}\n"
@@ -82,6 +83,12 @@
   "namespace.vndk.asan.search.paths += /system/${LIB}/vndk\n"
   "namespace.vndk.links = default\n"
   "namespace.vndk.link.default.allow_all_shared_libs = true\n"
+  "namespace.vndk.link.vndk_in_system.allow_all_shared_libs = true\n"
+  "namespace.vndk_in_system.isolated = true\n"
+  "namespace.vndk_in_system.visible = true\n"
+  "namespace.vndk_in_system.search.paths = /system/${LIB}\n"
+  "namespace.vndk_in_system.permitted.paths = /system/${LIB}\n"
+  "namespace.vndk_in_system.whitelisted = libz.so:libyuv.so:libtinyxml2.so\n"
   "\n";
 
 static bool write_version(const std::string& path, uint32_t version) {
@@ -165,20 +172,24 @@
   ASSERT_FALSE(default_ns_links[1].allow_all_shared_libs());
 
   auto& ns_configs = config->namespace_configs();
-  ASSERT_EQ(3U, ns_configs.size());
+  ASSERT_EQ(4U, ns_configs.size());
 
   // find second namespace
   const NamespaceConfig* ns_system = nullptr;
   const NamespaceConfig* ns_vndk = nullptr;
+  const NamespaceConfig* ns_vndk_in_system = nullptr;
   for (auto& ns : ns_configs) {
     std::string ns_name = ns->name();
-    ASSERT_TRUE(ns_name == "system" || ns_name == "default" || ns_name == "vndk")
+    ASSERT_TRUE(ns_name == "system" || ns_name == "default" ||
+                ns_name == "vndk" || ns_name == "vndk_in_system")
         << "unexpected ns name: " << ns->name();
 
     if (ns_name == "system") {
       ns_system = ns.get();
     } else if (ns_name == "vndk") {
       ns_vndk = ns.get();
+    } else if (ns_name == "vndk_in_system") {
+      ns_vndk_in_system = ns.get();
     }
   }
 
@@ -199,6 +210,11 @@
   ASSERT_EQ(1U, ns_vndk_links.size());
   ASSERT_EQ("default", ns_vndk_links[0].ns_name());
   ASSERT_TRUE(ns_vndk_links[0].allow_all_shared_libs());
+
+  ASSERT_TRUE(ns_vndk_in_system != nullptr) << "vndk_in_system namespace was not found";
+  ASSERT_EQ(
+      std::vector<std::string>({"libz.so", "libyuv.so", "libtinyxml2.so"}),
+      ns_vndk_in_system->whitelisted_libs());
 }
 
 TEST(linker_config, smoke) {
diff --git a/linker/linker_namespaces.cpp b/linker/linker_namespaces.cpp
index fd72cdc..e870ef7 100644
--- a/linker/linker_namespaces.cpp
+++ b/linker/linker_namespaces.cpp
@@ -38,6 +38,14 @@
     return true;
   }
 
+  if (!whitelisted_libs_.empty()) {
+    const char *lib_name = basename(file.c_str());
+    if (std::find(whitelisted_libs_.begin(), whitelisted_libs_.end(),
+                  lib_name) == whitelisted_libs_.end()) {
+      return false;
+    }
+  }
+
   for (const auto& dir : ld_library_paths_) {
     if (file_is_in_dir(file, dir)) {
       return true;
diff --git a/linker/linker_namespaces.h b/linker/linker_namespaces.h
index cd8b09d..31aeeb6 100644
--- a/linker/linker_namespaces.h
+++ b/linker/linker_namespaces.h
@@ -110,6 +110,16 @@
     permitted_paths_ = permitted_paths;
   }
 
+  const std::vector<std::string>& get_whitelisted_libs() const {
+    return whitelisted_libs_;
+  }
+  void set_whitelisted_libs(std::vector<std::string>&& whitelisted_libs) {
+    whitelisted_libs_ = whitelisted_libs;
+  }
+  void set_whitelisted_libs(const std::vector<std::string>& whitelisted_libs) {
+    whitelisted_libs_ = whitelisted_libs;
+  }
+
   const std::vector<android_namespace_link_t>& linked_namespaces() const {
     return linked_namespaces_;
   }
@@ -157,6 +167,7 @@
   std::vector<std::string> ld_library_paths_;
   std::vector<std::string> default_library_paths_;
   std::vector<std::string> permitted_paths_;
+  std::vector<std::string> whitelisted_libs_;
   // Loader looks into linked namespace if it was not able
   // to find a library in this namespace. Note that library
   // lookup in linked namespaces are limited by the list of