LU-12678 lnet: fix small race in unloading klnd modules.

[fs/lustre-release.git] / lnet / lnet / api-ni.c

diff --git a/lnet/lnet/api-ni.c b/lnet/lnet/api-ni.c
index 966f38b..399acdb 100644 (file)
--- a/lnet/lnet/api-ni.c
+++ b/lnet/lnet/api-ni.c
@@ -2062,7 +2062,14 @@ lnet_clear_zombies_nis_locked(struct lnet_net *net)
                islo = ni->ni_net->net_lnd->lnd_type == LOLND;
 
                LASSERT(!in_interrupt());
+               /* Holding the mutex makes it safe for lnd_shutdown
+                * to call module_put(). Module unload cannot finish
+                * until lnet_unregister_lnd() completes, and that
+                * requires the mutex.
+                */
+               mutex_lock(&the_lnet.ln_lnd_mutex);
                (net->net_lnd->lnd_shutdown)(ni);
+               mutex_unlock(&the_lnet.ln_lnd_mutex);
 
                if (!islo)
                        CDEBUG(D_LNI, "Removed LNI %s\n",