diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 0e60dbc..256d09d 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -195,11 +195,11 @@ shm_mq_set_receiver(shm_mq *mq, PGPROC *proc)
 	volatile shm_mq *vmq = mq;
 	PGPROC	   *sender;
 
-	SpinLockAcquire(&mq->mq_mutex);
+	SpinLockAcquire(&vmq->mq_mutex);
 	Assert(vmq->mq_receiver == NULL);
 	vmq->mq_receiver = proc;
 	sender = vmq->mq_sender;
-	SpinLockRelease(&mq->mq_mutex);
+	SpinLockRelease(&vmq->mq_mutex);
 
 	if (sender != NULL)
 		SetLatch(&sender->procLatch);
@@ -214,11 +214,11 @@ shm_mq_set_sender(shm_mq *mq, PGPROC *proc)
 	volatile shm_mq *vmq = mq;
 	PGPROC	   *receiver;
 
-	SpinLockAcquire(&mq->mq_mutex);
+	SpinLockAcquire(&vmq->mq_mutex);
 	Assert(vmq->mq_sender == NULL);
 	vmq->mq_sender = proc;
 	receiver = vmq->mq_receiver;
-	SpinLockRelease(&mq->mq_mutex);
+	SpinLockRelease(&vmq->mq_mutex);
 
 	if (receiver != NULL)
 		SetLatch(&receiver->procLatch);
@@ -233,9 +233,9 @@ shm_mq_get_receiver(shm_mq *mq)
 	volatile shm_mq *vmq = mq;
 	PGPROC	   *receiver;
 
-	SpinLockAcquire(&mq->mq_mutex);
+	SpinLockAcquire(&vmq->mq_mutex);
 	receiver = vmq->mq_receiver;
-	SpinLockRelease(&mq->mq_mutex);
+	SpinLockRelease(&vmq->mq_mutex);
 
 	return receiver;
 }
@@ -249,9 +249,9 @@ shm_mq_get_sender(shm_mq *mq)
 	volatile shm_mq *vmq = mq;
 	PGPROC	   *sender;
 
-	SpinLockAcquire(&mq->mq_mutex);
+	SpinLockAcquire(&vmq->mq_mutex);
 	sender = vmq->mq_sender;
-	SpinLockRelease(&mq->mq_mutex);
+	SpinLockRelease(&vmq->mq_mutex);
 
 	return sender;
 }