From 33f9018f7f6efe3796b02de759358e523c778c5e Mon Sep 17 00:00:00 2001
From: kn <kn@openbsd.org>
Date: Tue, 8 Nov 2022 21:07:33 +0000
Subject: [PATCH] Revert lock changes inside ifioctl_get()

WITNESS isn't happy with r1.667 "Push kernel lock into ifioctl_get()", so
revert it (including r1.668 and r1.669 depending on it):

	witness: userret: returning with the following locks held:
	exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82455f58)
	#0  witness_lock+0x311
	#1  ifioctl_get+0x2e
	#2  sys_ioctl+0x2c4
	#3  syscall+0x384
	#4  Xsyscall+0x128
	panic: witness_warn
	Stopped at      db_enter+0x10:  popq    %rbp
	    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
	* 70588  52613      0         0x3          0    4K pfctl

So back to the drawing board while leaving documentation bits (r1.670).
Thanks Hrvoje.
---
 sys/net/if.c | 20 ++++----------------
 1 file changed, 4 insertions(+), 16 deletions(-)

diff --git a/sys/net/if.c b/sys/net/if.c
index 9cb801b0010..297eac6afeb 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if.c,v 1.671 2022/11/08 18:47:58 kn Exp $	*/
+/*	$OpenBSD: if.c,v 1.672 2022/11/08 21:07:33 kn Exp $	*/
 /*	$NetBSD: if.c,v 1.35 1996/05/07 05:26:04 thorpej Exp $	*/
 
 /*
@@ -1980,7 +1980,9 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
 	case SIOCGIFRDOMAIN:
 	case SIOCGIFGROUP:
 	case SIOCGIFLLPRIO:
+		KERNEL_LOCK();
 		error = ifioctl_get(cmd, data);
+		KERNEL_UNLOCK();
 		return (error);
 	}
 
@@ -2429,45 +2431,33 @@ ifioctl_get(u_long cmd, caddr_t data)
 
 	switch(cmd) {
 	case SIOCGIFCONF:
-		KERNEL_LOCK();
 		NET_LOCK_SHARED();
 		error = ifconf(data);
 		NET_UNLOCK_SHARED();
-		KERNEL_UNLOCK();
 		return (error);
 	case SIOCIFGCLONERS:
 		error = if_clone_list((struct if_clonereq *)data);
 		return (error);
 	case SIOCGIFGMEMB:
-		KERNEL_LOCK();
 		NET_LOCK_SHARED();
 		error = if_getgroupmembers(data);
 		NET_UNLOCK_SHARED();
-		KERNEL_UNLOCK();
 		return (error);
 	case SIOCGIFGATTR:
-		KERNEL_LOCK();
 		NET_LOCK_SHARED();
 		error = if_getgroupattribs(data);
 		NET_UNLOCK_SHARED();
-		KERNEL_UNLOCK();
 		return (error);
 	case SIOCGIFGLIST:
-		KERNEL_LOCK();
 		NET_LOCK_SHARED();
 		error = if_getgrouplist(data);
 		NET_UNLOCK_SHARED();
-		KERNEL_UNLOCK();
 		return (error);
 	}
 
-	KERNEL_LOCK();
-
 	ifp = if_unit(ifr->ifr_name);
-	if (ifp == NULL) {
-		KERNEL_UNLOCK();
+	if (ifp == NULL)
 		return (ENXIO);
-	}
 
 	NET_LOCK_SHARED();
 
@@ -2539,8 +2529,6 @@ ifioctl_get(u_long cmd, caddr_t data)
 
 	NET_UNLOCK_SHARED();
 
-	KERNEL_UNLOCK();
-
 	if_put(ifp);
 
 	return (error);
-- 
2.20.1