3 files changed, 10 insertions, 3 deletions
diff --git a/sys/src/9/ip/ip.c b/sys/src/9/ip/ip.c
index 9f7bfa0a0..7f197b22b 100644
--- a/sys/src/9/ip/ip.c
+++ b/sys/src/9/ip/ip.c
@@ -123,7 +123,10 @@ ipoput4(Fs *f, Block *bp, int gating, int ttl, int tos, Routehint *rh)
 	else
 		gate = r->v4.gate;
 
-	rlock(ifc);
+	if(!canrlock(ifc)){
+		ip->stats[OutDiscards]++;
+		goto free;
+	}
 	if(waserror()){
 		runlock(ifc);
 		nexterror();
diff --git a/sys/src/9/ip/ipifc.c b/sys/src/9/ip/ipifc.c
index 7af840991..9dd55f93b 100644
--- a/sys/src/9/ip/ipifc.c
+++ b/sys/src/9/ip/ipifc.c
@@ -1167,7 +1167,8 @@ findipifc(Fs *f, uchar *local, uchar *remote, int type)
 	xspec = 0;
 	for(cp = f->ipifc->conv; *cp != nil; cp++){
 		ifc = (Ipifc*)(*cp)->ptcl;
-		rlock(ifc);
+		if(!canrlock(ifc))
+			continue;
 		for(lifc = ifc->lifc; lifc != nil; lifc = lifc->next){
 			if(type & Runi){
 				if(ipcmp(remote, lifc->local) == 0){
diff --git a/sys/src/9/ip/ipv6.c b/sys/src/9/ip/ipv6.c
index 7d7cdc09a..1d8750cde 100644
--- a/sys/src/9/ip/ipv6.c
+++ b/sys/src/9/ip/ipv6.c
@@ -76,7 +76,10 @@ ipoput6(Fs *f, Block *bp, int gating, int ttl, int tos, Routehint *rh)
 	else
 		gate = r->v6.gate;
 
-	rlock(ifc);
+	if(!canrlock(ifc)){
+		ip->stats[OutDiscards]++;
+		goto free;
+	}
 	if(waserror()){
 		runlock(ifc);
 		nexterror();