diff --git a/sys/amd64/linux/linux_ptrace.c b/sys/amd64/linux/linux_ptrace.c
--- a/sys/amd64/linux/linux_ptrace.c
+++ b/sys/amd64/linux/linux_ptrace.c
@@ -84,7 +84,8 @@
 #define	LINUX_PTRACE_O_EXITKILL		1048576
 #define	LINUX_PTRACE_O_SUSPEND_SECCOMP	2097152
 
-#define	LINUX_NT_PRSTATUS		1
+#define	LINUX_NT_PRSTATUS		0x1
+#define	LINUX_NT_X86_XSTATE		0x202
 
 #define	LINUX_PTRACE_O_MASK	(LINUX_PTRACE_O_TRACESYSGOOD |	\
     LINUX_PTRACE_O_TRACEFORK | LINUX_PTRACE_O_TRACEVFORK |	\
@@ -540,8 +541,12 @@
 	switch (addr) {
 	case LINUX_NT_PRSTATUS:
 		return (linux_ptrace_getregset_prstatus(td, pid, data));
+	case LINUX_NT_X86_XSTATE:
+		linux_msg(td, "PTRAGE_GETREGSET NT_X86_XSTATE not implemented; "
+		    "returning EINVAL");
+		return (EINVAL);
 	default:
-		linux_msg(td, "PTRACE_GETREGSET request %ld not implemented; "
+		linux_msg(td, "PTRACE_GETREGSET request %#lx not implemented; "
 		    "returning EINVAL", addr);
 		return (EINVAL);
 	}