From 7816b86f755aeba9deb9ea647c6d39e03f061120 Mon Sep 17 00:00:00 2001
From: kn <kn@openbsd.org>
Date: Wed, 5 Apr 2023 23:01:03 +0000
Subject: [PATCH] Push kernel lock into nd6_resolve()

Tested as part of bigger unlock diffs, commit now as tiny first step.

OK bluhm
---
 sys/net/if_ethersubr.c | 8 +-------
 sys/netinet6/nd6.c     | 8 +++++++-
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/sys/net/if_ethersubr.c b/sys/net/if_ethersubr.c
index ec826664177..584ee5582ec 100644
--- a/sys/net/if_ethersubr.c
+++ b/sys/net/if_ethersubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ethersubr.c,v 1.287 2023/02/06 20:27:45 jan Exp $	*/
+/*	$OpenBSD: if_ethersubr.c,v 1.288 2023/04/05 23:01:03 kn Exp $	*/
 /*	$NetBSD: if_ethersubr.c,v 1.19 1996/05/07 02:40:30 thorpej Exp $	*/
 
 /*
@@ -248,10 +248,7 @@ ether_resolve(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 		break;
 #ifdef INET6
 	case AF_INET6:
-		KERNEL_LOCK();
-		/* XXXSMP there is a MP race in nd6_resolve() */
 		error = nd6_resolve(ifp, rt, m, dst, eh->ether_dhost);
-		KERNEL_UNLOCK();
 		if (error)
 			return (error);
 		eh->ether_type = htons(ETHERTYPE_IPV6);
@@ -277,10 +274,7 @@ ether_resolve(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 			break;
 #ifdef INET6
 		case AF_INET6:
-			KERNEL_LOCK();
-			/* XXXSMP there is a MP race in nd6_resolve() */
 			error = nd6_resolve(ifp, rt, m, dst, eh->ether_dhost);
-			KERNEL_UNLOCK();
 			if (error)
 				return (error);
 			break;
diff --git a/sys/netinet6/nd6.c b/sys/netinet6/nd6.c
index 591a4688b37..5e4d00e8bc4 100644
--- a/sys/netinet6/nd6.c
+++ b/sys/netinet6/nd6.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: nd6.c,v 1.271 2023/04/05 21:51:47 bluhm Exp $	*/
+/*	$OpenBSD: nd6.c,v 1.272 2023/04/05 23:01:03 kn Exp $	*/
 /*	$KAME: nd6.c,v 1.280 2002/06/08 19:52:07 itojun Exp $	*/
 
 /*
@@ -1254,12 +1254,15 @@ nd6_resolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
 		return (0);
 	}
 
+	/* XXXSMP there is a MP race in nd6_resolve() */
+	KERNEL_LOCK();
 	uptime = getuptime();
 	rt = rt_getll(rt0);
 
 	if (ISSET(rt->rt_flags, RTF_REJECT) &&
 	    (rt->rt_expire == 0 || rt->rt_expire > uptime)) {
 		m_freem(m);
+		KERNEL_UNLOCK();
 		return (rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
 	}
 
@@ -1323,6 +1326,7 @@ nd6_resolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
 		}
 
 		bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
+		KERNEL_UNLOCK();
 		return (0);
 	}
 
@@ -1355,10 +1359,12 @@ nd6_resolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
 		nd6_llinfo_settimer(ln, RETRANS_TIMER / 1000);
 		nd6_ns_output(ifp, NULL, &satosin6(dst)->sin6_addr, ln, 0);
 	}
+	KERNEL_UNLOCK();
 	return (EAGAIN);
 
 bad:
 	m_freem(m);
+	KERNEL_UNLOCK();
 	return (EINVAL);
 }
 
-- 
2.20.1