crashes in nd6_llinfo_timer...

[christos%zoulas.com@localhost (Christos Zoulas)]

I filed http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=55030
and I've been trying to fix it myself since my machine crashes every
couple of days... This is working for me so far, and unless someone
comes up with something better, I will commit it soon (with out the
messages).

Yes, it does work:

[10:08pm] 30>dmesg -T | grep oof
[Thu Mar 26 16:43:51 EDT 2020] in6_lltable_lookup: oof did not crash
[10:08pm] 31>uptime
10:09PM  up 3 days,  2:23, 1 user, load averages: 0.00, 0.00, 0.00

christos


Index: in6.c
===================================================================
RCS file: /cvsroot/src/sys/netinet6/in6.c,v
retrieving revision 1.277
diff -u -u -r1.277 in6.c
--- in6.c	20 Jan 2020 18:38:22 -0000	1.277
+++ in6.c	28 Mar 2020 02:08:01 -0000
@@ -2652,10 +2652,14 @@
 	if (lle == NULL)
 		return NULL;
 
-	if (flags & LLE_EXCLUSIVE)
-		LLE_WLOCK(lle);
-	else
-		LLE_RLOCK(lle);
+	LLE_RLOCK(lle);
+	if (flags & LLE_EXCLUSIVE) {
+		if (!LLE_TRY_UPGRADE(lle)) {
+			LLE_RUNLOCK(lle);
+			printf("%s: oof did not crash\n", __func__);
+			return NULL;
+		}
+	}
 	return lle;
 }
 
Index: nd6.c
===================================================================
RCS file: /cvsroot/src/sys/netinet6/nd6.c,v
retrieving revision 1.267
diff -u -u -r1.267 nd6.c
--- nd6.c	9 Mar 2020 21:20:56 -0000	1.267
+++ nd6.c	28 Mar 2020 02:08:02 -0000
@@ -466,7 +466,12 @@
 
 	SOFTNET_KERNEL_LOCK_UNLESS_NET_MPSAFE();
 
-	LLE_WLOCK(ln);
+	LLE_RLOCK(ln);
+	if (!LLE_TRY_UPGRADE(ln)) {
+		LLE_RUNLOCK(ln);
+		printf("%s: oof did not crash\n", __func__);
+		goto out;
+	}
 	if ((ln->la_flags & LLE_LINKED) == 0)
 		goto out;
 	if (ln->ln_ntick > 0) {