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
@@ -44,6 +44,7 @@
 #include <amd64/linux/linux.h>
 #include <amd64/linux/linux_proto.h>
 #include <compat/linux/linux_emul.h>
+#include <compat/linux/linux_errno.h>
 #include <compat/linux/linux_misc.h>
 #include <compat/linux/linux_signal.h>
 #include <compat/linux/linux_util.h>
@@ -639,6 +640,9 @@
 			 * the ptracing process fall back to another method.
 			 */
 			si.op = LINUX_PTRACE_SYSCALL_INFO_NONE;
+		} else if (sr.sr_error == ERESTART) {
+			si.exit.rval = -LINUX_ERESTARTSYS;
+			si.exit.is_error = 1;
 		} else {
 			si.exit.rval = bsd_to_linux_errno(sr.sr_error);
 			si.exit.is_error = 1;
diff --git a/sys/compat/linux/linux_errno.h b/sys/compat/linux/linux_errno.h
--- a/sys/compat/linux/linux_errno.h
+++ b/sys/compat/linux/linux_errno.h
@@ -182,4 +182,10 @@
 
 #define	LINUX_ELAST		LINUX_EHWPOISON
 
+/*
+ * This is a special "internal" errno that must never be returned
+ * to a Linux process, but might be observed via ptrace(2).
+ */
+#define	LINUX_ERESTARTSYS	512
+
 #endif /* _LINUX_ERRNO_H_ */