NET_LOCK in sppp_keepalive

[Alexander Bluhm]

Hi,

My static code analysis has found a missing netlock.  Starting from
a given function it finds reverse traces that have no NET_LOCK().

Lock not found: [CGNode: if_linkstate, CGNode: if_down, CGNode: sppp_keepalive]

Manual inspection shows that the last function is used in a timeout.

timeout_set(&keepalive_ch, sppp_keepalive, NULL);

ok?

bluhm

Index: net/if_spppsubr.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/net/if_spppsubr.c,v
retrieving revision 1.158
diff -u -p -r1.158 if_spppsubr.c
--- net/if_spppsubr.c   2 Jan 2017 08:41:21 -0000       1.158
+++ net/if_spppsubr.c   5 Jan 2017 21:34:39 -0000
@@ -4050,9 +4050,10 @@ void
 sppp_keepalive(void *dummy)
 {
        struct sppp *sp;
-       int s;
+       int s, sl;
        struct timeval tv;
 
+       NET_LOCK(sl);
        s = splnet();
        getmicrouptime(&tv);
        for (sp=spppq; sp; sp=sp->pp_next) {
@@ -4104,6 +4105,7 @@ sppp_keepalive(void *dummy)
                }
        }
        splx(s);
+       NET_UNLOCK(sl);
        timeout_add_sec(&keepalive_ch, 10);
 }