diff --git a/compiler-rt/include/sanitizer/linux_syscall_hooks.h b/compiler-rt/include/sanitizer/linux_syscall_hooks.h
--- a/compiler-rt/include/sanitizer/linux_syscall_hooks.h
+++ b/compiler-rt/include/sanitizer/linux_syscall_hooks.h
@@ -3077,6 +3077,8 @@
                                                long oldact, long sz);
 void __sanitizer_syscall_post_impl_rt_sigaction(long res, long signum, long act,
                                                 long oldact, long sz);
+void __sanitizer_syscall_pre_impl_sigaltstack(const void *ss, void *oss);
+void __sanitizer_syscall_post_impl_sigaltstack(long res, void *ss, void *oss);
 #ifdef __cplusplus
 }  // extern "C"
 #endif