1 files changed, 9 insertions, 2 deletions

diff --git a/sys/dev/pccbb/pccbb.c b/sys/dev/pccbb/pccbb.c
index f60118528ff8..a0585b00b8ea 100644
--- a/sys/dev/pccbb/pccbb.c
+++ b/sys/dev/pccbb/pccbb.c
@@ -464,7 +464,14 @@ cbb_event_thread(void *arg)
 	sc->flags |= CBB_KTHREAD_RUNNING;
 	while ((sc->flags & CBB_KTHREAD_DONE) == 0) {
 		mtx_unlock(&sc->mtx);
-		newbus_xlock();
+		/*
+		 * We take out Giant here because we need it deep,
+		 * down in the bowels of the vm system for mapping the
+		 * memory we need to read the CIS.  In addition, since
+		 * we are adding/deleting devices from the dev tree,
+		 * and that code isn't MP safe, we have to hold Giant.
+		 */
+		mtx_lock(&Giant);
 		status = cbb_get(sc, CBB_SOCKET_STATE);
 		DPRINTF(("Status is 0x%x\n", status));
 		if (!CBB_CARD_PRESENT(status)) {
@@ -490,7 +497,7 @@ cbb_event_thread(void *arg)
 			not_a_card = 0;		/* We know card type */
 			cbb_insert(sc);
 		}
-		newbus_xunlock();
+		mtx_unlock(&Giant);
 
 		/*
 		 * First time through we need to tell mountroot that we're