From: claudio <claudio@openbsd.org>
Date: Mon, 30 Oct 2023 07:13:10 +0000 (+0000)
Subject: Use ERESTART for any single_thread_set() error in sys_execve().
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=14835c3890bbdea732ae0a163f6ab26b53c828be;p=openbsd

Use ERESTART for any single_thread_set() error in sys_execve().

If single thread is already held by another thread just unwind to userret()
wait there and retry the system call later (if at all).
OK mpi@
---

diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index a85010da5ae..9d8ec981347 100644
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_exec.c,v 1.251 2023/09/29 12:47:34 claudio Exp $	*/
+/*	$OpenBSD: kern_exec.c,v 1.252 2023/10/30 07:13:10 claudio Exp $	*/
 /*	$NetBSD: kern_exec.c,v 1.75 1996/02/09 18:59:28 christos Exp $	*/
 
 /*-
@@ -283,9 +283,12 @@ sys_execve(struct proc *p, void *v, register_t *retval)
 		return (0);
 	}
 
-	/* get other threads to stop */
-	if ((error = single_thread_set(p, SINGLE_UNWIND | SINGLE_DEEP)))
-		return (error);
+	/*
+	 * Get other threads to stop, if contested return ERESTART,
+	 * so the syscall is restarted after halting in userret.
+	 */
+	if (single_thread_set(p, SINGLE_UNWIND | SINGLE_DEEP))
+		return (ERESTART);
 
 	/*
 	 * Cheap solution to complicated problems.