diff --git a/libc/include/android/dlext.h b/libc/include/android/dlext.h
index f0b731c..f216aab 100644
--- a/libc/include/android/dlext.h
+++ b/libc/include/android/dlext.h
@@ -157,7 +157,7 @@
   uint64_t flags;
 
   /** Used by `ANDROID_DLEXT_RESERVED_ADDRESS` and `ANDROID_DLEXT_RESERVED_ADDRESS_HINT`. */
-  void*   reserved_addr;
+  void*   _Nullable reserved_addr;
   /** Used by `ANDROID_DLEXT_RESERVED_ADDRESS` and `ANDROID_DLEXT_RESERVED_ADDRESS_HINT`. */
   size_t  reserved_size;
 
@@ -170,7 +170,7 @@
   off64_t library_fd_offset;
 
   /** Used by `ANDROID_DLEXT_USE_NAMESPACE`. */
-  struct android_namespace_t* library_namespace;
+  struct android_namespace_t* _Nullable library_namespace;
 } android_dlextinfo;
 
 /**
@@ -180,7 +180,7 @@
  *
  * Available since API level 21.
  */
-void* android_dlopen_ext(const char* __filename, int __flags, const android_dlextinfo* __info)
+void* _Nullable android_dlopen_ext(const char* _Nullable __filename, int __flags, const android_dlextinfo* _Nullable __info)
   __INTRODUCED_IN(21);
 
 __END_DECLS
diff --git a/libc/include/android/fdsan.h b/libc/include/android/fdsan.h
index 59ce133..3de0649 100644
--- a/libc/include/android/fdsan.h
+++ b/libc/include/android/fdsan.h
@@ -159,7 +159,7 @@
  *
  * 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) __INTRODUCED_IN(29);
+const char* _Nonnull android_fdsan_get_tag_type(uint64_t tag) __INTRODUCED_IN(29);
 
 /*
  * Get an owner tag's value, with the type masked off.
diff --git a/libc/include/android/legacy_stdlib_inlines.h b/libc/include/android/legacy_stdlib_inlines.h
index e9b606a..f0985fe 100644
--- a/libc/include/android/legacy_stdlib_inlines.h
+++ b/libc/include/android/legacy_stdlib_inlines.h
@@ -38,15 +38,15 @@
 
 __BEGIN_DECLS
 
-static __inline double strtod_l(const char* __s, char** __end_ptr, locale_t __l) {
+static __inline double strtod_l(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, locale_t _Nonnull __l) {
   return strtod(__s, __end_ptr);
 }
 
-static __inline float strtof_l(const char* __s, char** __end_ptr, locale_t __l) {
+static __inline float strtof_l(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, locale_t _Nonnull __l) {
   return strtof(__s, __end_ptr);
 }
 
-static __inline long strtol_l(const char* __s, char** __end_ptr, int __base, locale_t __l) {
+static __inline long strtol_l(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, int __base, locale_t _Nonnull __l) {
   return strtol(__s, __end_ptr, __base);
 }
 
diff --git a/libc/include/android/set_abort_message.h b/libc/include/android/set_abort_message.h
index 5d8d8ee..2be01a9 100644
--- a/libc/include/android/set_abort_message.h
+++ b/libc/include/android/set_abort_message.h
@@ -46,6 +46,6 @@
  *
  * Available since API level 21.
  */
-void android_set_abort_message(const char* __msg) __INTRODUCED_IN(21);
+void android_set_abort_message(const char* _Nullable __msg) __INTRODUCED_IN(21);
 
 __END_DECLS
diff --git a/libc/include/sys/ipc.h b/libc/include/sys/ipc.h
index c81ec1a..2e2b8cf 100644
--- a/libc/include/sys/ipc.h
+++ b/libc/include/sys/ipc.h
@@ -52,6 +52,6 @@
  *
  * Returns a key on success, and returns -1 and sets `errno` on failure.
  */
-key_t ftok(const char* __path, int __id);
+key_t ftok(const char* _Nonnull __path, int __id);
 
 __END_DECLS
diff --git a/libc/include/sys/random.h b/libc/include/sys/random.h
index be52bd9..0251176 100644
--- a/libc/include/sys/random.h
+++ b/libc/include/sys/random.h
@@ -50,7 +50,7 @@
  *
  * See also arc4random_buf() which is available in all API levels.
  */
-int getentropy(void* __buffer, size_t __buffer_size) __wur __INTRODUCED_IN(28);
+int getentropy(void* _Nonnull __buffer, size_t __buffer_size) __wur __INTRODUCED_IN(28);
 
 /**
  * [getrandom(2)](http://man7.org/linux/man-pages/man2/getrandom.2.html) fills the given buffer
@@ -62,6 +62,6 @@
  *
  * See also arc4random_buf() which is available in all API levels.
  */
-ssize_t getrandom(void* __buffer, size_t __buffer_size, unsigned int __flags) __wur __INTRODUCED_IN(28);
+ssize_t getrandom(void* _Nonnull __buffer, size_t __buffer_size, unsigned int __flags) __wur __INTRODUCED_IN(28);
 
 __END_DECLS
diff --git a/libc/include/sys/sendfile.h b/libc/include/sys/sendfile.h
index 60bbde8..4b00d5d 100644
--- a/libc/include/sys/sendfile.h
+++ b/libc/include/sys/sendfile.h
@@ -40,7 +40,7 @@
 
 /* See https://android.googlesource.com/platform/bionic/+/master/docs/32-bit-abi.md */
 #if defined(__USE_FILE_OFFSET64)
-ssize_t sendfile(int __out_fd, int __in_fd, off_t* __offset, size_t __count) __RENAME(sendfile64) __INTRODUCED_IN(21);
+ssize_t sendfile(int __out_fd, int __in_fd, off_t* _Nullable __offset, size_t __count) __RENAME(sendfile64) __INTRODUCED_IN(21);
 #else
 /**
  * [sendfile(2)](http://man7.org/linux/man-pages/man2/sendfile.2.html) copies data directly
@@ -50,13 +50,13 @@
  *
  * Available since API level 21.
  */
-ssize_t sendfile(int __out_fd, int __in_fd, off_t* __offset, size_t __count);
+ssize_t sendfile(int __out_fd, int __in_fd, off_t* _Nullable __offset, size_t __count);
 #endif
 
 /**
  * Like sendfile() but allows using a 64-bit offset
  * even from a 32-bit process without `__FILE_OFFSET_BITS=64`.
  */
-ssize_t sendfile64(int __out_fd, int __in_fd, off64_t* __offset, size_t __count) __INTRODUCED_IN(21);
+ssize_t sendfile64(int __out_fd, int __in_fd, off64_t* _Nullable __offset, size_t __count) __INTRODUCED_IN(21);
 
 __END_DECLS
diff --git a/tests/sys_random_test.cpp b/tests/sys_random_test.cpp
index 2e2665b..e0cbf78 100644
--- a/tests/sys_random_test.cpp
+++ b/tests/sys_random_test.cpp
@@ -48,6 +48,8 @@
 }
 
 TEST(sys_random, getentropy_EFAULT) {
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wnonnull"
 #if defined(HAVE_SYS_RANDOM)
   errno = 0;
   ASSERT_EQ(-1, getentropy(nullptr, 1));
@@ -55,6 +57,7 @@
 #else
   GTEST_SKIP() << "<sys/random.h> not available";
 #endif
+#pragma clang diagnostic pop
 }
 
 TEST(sys_random, getentropy_EIO) {
@@ -84,6 +87,8 @@
 }
 
 TEST(sys_random, getrandom_EFAULT) {
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wnonnull"
 #if defined(HAVE_SYS_RANDOM)
   errno = 0;
   ASSERT_EQ(-1, getrandom(nullptr, 256, 0));
@@ -91,6 +96,7 @@
 #else
   GTEST_SKIP() << "<sys/random.h> not available";
 #endif
+#pragma clang diagnostic pop
 }
 
 TEST(sys_random, getrandom_EINVAL) {