OS-328 dlmgmtd/mac_link_flow_add() deadlock

1 files changed, 29 insertions, 3 deletions

diff --git a/usr/src/cmd/dlmgmtd/dlmgmt_door.c b/usr/src/cmd/dlmgmtd/dlmgmt_door.c
index b80ffcc280..e3e7fccd84 100644
--- a/usr/src/cmd/dlmgmtd/dlmgmt_door.c
+++ b/usr/src/cmd/dlmgmtd/dlmgmt_door.c
@@ -59,6 +59,7 @@
 #include <libsysevent.h>
 #include <libdlmgmt.h>
 #include <librcm.h>
+#include <thread.h>
 #include "dlmgmt_impl.h"
 
 typedef void dlmgmt_door_handler_t(void *, void *, size_t *, zoneid_t,
@@ -1317,6 +1318,14 @@ done:
 	retvalp->lr_err = err;
 }
 
+static void
+do_zonehalt(void *zid)
+{
+	dlmgmt_table_lock(B_TRUE);
+	dlmgmt_db_fini((zoneid_t)zid);
+	dlmgmt_table_unlock();
+}
+
 /* ARGSUSED */
 static void
 dlmgmt_zonehalt(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
@@ -1332,9 +1341,26 @@ dlmgmt_zonehalt(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
 		} else if (zonehalt->ld_zoneid == GLOBAL_ZONEID) {
 			err = EINVAL;
 		} else {
-			dlmgmt_table_lock(B_TRUE);
-			dlmgmt_db_fini(zonehalt->ld_zoneid);
-			dlmgmt_table_unlock();
+			/*
+			 * dlmgmt_db_fini makes ioctls which lead to the
+			 * following kernel stack:
+			 *     vnic_ioc_delete
+			 *     vnic_dev_delete
+			 *     dls_devnet_destroy
+			 * dls_devnet_destroy calls mac_perim_enter_by_mh
+			 * which could lead to deadlock if another process is
+			 * holding the mac perimeter then made an upcall to
+			 * dlmgmtd.  To avoid this, we run the dlmgmt_db_fini
+			 * in a thread so that we can continue to service
+			 * upcalls in parallel with cleaning up zones.
+			 */
+			err = thr_create(NULL, 0,
+			    (void *(*)(void *))do_zonehalt,
+			    (void *)(zonehalt->ld_zoneid), THR_DAEMON, NULL);
+			if (err != 0)
+				dlmgmt_log(LOG_ERR, "unable to create thread "
+				    "to clean up zone %d: %s",
+				    zonehalt->ld_zoneid, strerror(err));
 		}
 	}
 	retvalp->lr_err = err;