diff --git a/sys/kern/sysv_sem.c b/sys/kern/sysv_sem.c
index bea78326f889..80d07ba8dc38 100644
--- a/sys/kern/sysv_sem.c
+++ b/sys/kern/sysv_sem.c
@@ -1166,6 +1166,13 @@ semop(td, uap)
 			goto done2;
 		}
 
+		/*
+		 * Renew the semaphore's pointer after wakeup since
+		 * during msleep sem_base may have been modified and semptr
+		 * is not valid any more
+		 */
+		semptr = &semakptr->u.sem_base[sopptr->sem_num];
+
 		/*
 		 * The semaphore is still alive.  Readjust the count of
 		 * waiting processes.