diff --git a/libc/arch-riscv64/bionic/__bionic_clone.S b/libc/arch-riscv64/bionic/__bionic_clone.S
index d535095..2827857 100644
--- a/libc/arch-riscv64/bionic/__bionic_clone.S
+++ b/libc/arch-riscv64/bionic/__bionic_clone.S
@@ -51,7 +51,7 @@
 .L_bc_failure:
   # Set errno if something went wrong.
   neg a0, a0
-  j __set_errno_internal
+  tail __set_errno_internal
 
 .L_bc_child:
   # We're in the child now. Set the end of the frame record chain.
@@ -62,5 +62,5 @@
   ld a0, 0(sp)
   ld a1, 8(sp)
   addi sp, sp, 16
-  j __start_thread
+  tail __start_thread
 END(__bionic_clone)
diff --git a/libc/arch-riscv64/bionic/syscall.S b/libc/arch-riscv64/bionic/syscall.S
index 7b9d3ca..1a6e60a 100644
--- a/libc/arch-riscv64/bionic/syscall.S
+++ b/libc/arch-riscv64/bionic/syscall.S
@@ -49,5 +49,5 @@
   ret
 1:
   neg a0, a0
-  j __set_errno_internal
+  tail __set_errno_internal
 END(syscall)
diff --git a/libc/arch-riscv64/bionic/vfork.S b/libc/arch-riscv64/bionic/vfork.S
index 0eff9e9..29ab405 100644
--- a/libc/arch-riscv64/bionic/vfork.S
+++ b/libc/arch-riscv64/bionic/vfork.S
@@ -62,5 +62,5 @@
 
 .L_failure:
   neg     a0, a0
-  j       __set_errno_internal
+  tail    __set_errno_internal
 END(vfork)
diff --git a/libc/include/assert.h b/libc/include/assert.h
index 79e7b86..8db970b 100644
--- a/libc/include/assert.h
+++ b/libc/include/assert.h
@@ -75,12 +75,12 @@
  * __assert() is called by assert() on failure. Most users want assert()
  * instead, but this can be useful for reporting other failures.
  */
-void __assert(const char* __file, int __line, const char* __msg) __noreturn;
+void __assert(const char* _Nonnull __file, int __line, const char* _Nonnull __msg) __noreturn;
 
 /**
  * __assert2() is called by assert() on failure. Most users want assert()
  * instead, but this can be useful for reporting other failures.
  */
-void __assert2(const char* __file, int __line, const char* __function, const char* __msg) __noreturn;
+void __assert2(const char* _Nonnull __file, int __line, const char* _Nonnull __function, const char* _Nonnull __msg) __noreturn;
 
 __END_DECLS
diff --git a/libc/include/sys/pidfd.h b/libc/include/sys/pidfd.h
index 6d0e809..30455bb 100644
--- a/libc/include/sys/pidfd.h
+++ b/libc/include/sys/pidfd.h
@@ -71,6 +71,6 @@
  *
  * Available since API level 31.
  */
-int pidfd_send_signal(int __pidfd, int __sig, siginfo_t *__info, unsigned int __flags) __INTRODUCED_IN(31);
+int pidfd_send_signal(int __pidfd, int __sig, siginfo_t * _Nullable __info, unsigned int __flags) __INTRODUCED_IN(31);
 
 __END_DECLS
diff --git a/libc/include/sys/utsname.h b/libc/include/sys/utsname.h
index 1fa3187..aa8c1a0 100644
--- a/libc/include/sys/utsname.h
+++ b/libc/include/sys/utsname.h
@@ -62,6 +62,6 @@
  *
  * Returns 0 on success, and returns -1 and sets `errno` on failure.
  */
-int uname(struct utsname* __buf);
+int uname(struct utsname* _Nonnull __buf);
 
 __END_DECLS