From: jca <jca@openbsd.org>
Date: Wed, 29 Jun 2022 12:06:11 +0000 (+0000)
Subject: Simplify the locking dance around pledge_syscall()
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=72dc29cb42e42b51c90ae9be538617d336a4c77f;p=openbsd

Simplify the locking dance around pledge_syscall()

It doesn't make sense to wrap this function with the kernel lock only
when the syscall to be executed is itself locked.  Instead
pledge_syscall() should be always safe to execute without the kernel
lock.

"looks good" kettenis@, ok deraadt@
---

diff --git a/sys/sys/syscall_mi.h b/sys/sys/syscall_mi.h
index 76f34e0b030..b535c0386f7 100644
--- a/sys/sys/syscall_mi.h
+++ b/sys/sys/syscall_mi.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: syscall_mi.h,v 1.25 2020/01/21 16:16:23 mpi Exp $	*/
+/*	$OpenBSD: syscall_mi.h,v 1.26 2022/06/29 12:06:11 jca Exp $	*/
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1993
@@ -89,16 +89,15 @@ mi_syscall(struct proc *p, register_t code, const struct sysent *callp,
 	    uvm_map_inentry_pc, p->p_vmspace->vm_map.wserial))
 		return (EPERM);
 
-	if (lock)
-		KERNEL_LOCK();
 	pledged = (p->p_p->ps_flags & PS_PLEDGE);
 	if (pledged && (error = pledge_syscall(p, code, &tval))) {
-		if (!lock)
-			KERNEL_LOCK();
+		KERNEL_LOCK();
 		error = pledge_fail(p, error, tval);
 		KERNEL_UNLOCK();
 		return (error);
 	}
+	if (lock)
+		KERNEL_LOCK();
 	error = (*callp->sy_call)(p, argp, retval);
 	if (lock)
 		KERNEL_UNLOCK();