1 files changed, 4 insertions, 2 deletions
diff --git a/os/rt/src/chcond.c b/os/rt/src/chcond.c
index cc3ee2e40..18c0e1c8c 100644
--- a/os/rt/src/chcond.c
+++ b/os/rt/src/chcond.c
@@ -210,7 +210,8 @@ msg_t chCondWaitS(condition_variable_t *cp) {
   chDbgCheck(cp != NULL);
   chDbgAssert(ctp->p_mtxlist != NULL, "not owning a mutex");
 
-  mp = chMtxUnlockS();
+  mp = chMtxGetNextMutex();
+  chMtxUnlockS(mp);
   ctp->p_u.wtobjp = cp;
   queue_prio_insert(ctp, &cp->c_queue);
   chSchGoSleepS(CH_STATE_WTCOND);
@@ -293,7 +294,8 @@ msg_t chCondWaitTimeoutS(condition_variable_t *cp, systime_t time) {
   chDbgCheck((cp != NULL) && (time != TIME_IMMEDIATE));
   chDbgAssert(currp->p_mtxlist != NULL, "not owning a mutex");
 
-  mp = chMtxUnlockS();
+  mp = chMtxGetNextMutex();
+  chMtxUnlockS(mp);
   currp->p_u.wtobjp = cp;
   queue_prio_insert(currp, &cp->c_queue);
   msg = chSchGoSleepTimeoutS(CH_STATE_WTCOND, time);