bugfix: mutex was invalidly left unlocked during action processingv5.8.2

At least one case where this can occur is during thread shutdown, which
may be initiated by lower activity. In most cases, this is quite
unlikely to happen. However, if it does, data structures may be
corrupted which could lead to fatal failure and segfault. I detected
this via a testbench test, not a user report. But I assume that some
users may have had unreproducable aborts that were cause by this bug.

1 files changed, 8 insertions, 4 deletions

diff --git a/runtime/queue.c b/runtime/queue.c
index 88e01a7a..00eb76c7 100644
--- a/runtime/queue.c
+++ b/runtime/queue.c
@@ -1678,6 +1678,7 @@ static rsRetVal
 ConsumerReg(qqueue_t *pThis, wti_t *pWti)
 {
 	int iCancelStateSave;
+	int bNeedReLock = 0;	/**< do we need to lock the mutex again? */
 	DEFiRet;
 
 	ISOBJ_TYPE_assert(pThis, qqueue);
@@ -1687,6 +1688,7 @@ ConsumerReg(qqueue_t *pThis, wti_t *pWti)
 
 	/* we now have a non-idle batch of work, so we can release the queue mutex and process it */
 	d_pthread_mutex_unlock(pThis->mut);
+	bNeedReLock = 1;
 
 	/* at this spot, we may be cancelled */
 	pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &iCancelStateSave);
@@ -1706,12 +1708,14 @@ ConsumerReg(qqueue_t *pThis, wti_t *pWti)
 	/* but now cancellation is no longer permitted */
 	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &iCancelStateSave);
 
-	/* now we are done, but need to re-aquire the mutex */
-	d_pthread_mutex_lock(pThis->mut);
-
 finalize_it:
-	dbgprintf("regular consumer finished, iret=%d, szlog %d sz phys %d\n", iRet,
+	DBGPRINTF("regular consumer finished, iret=%d, szlog %d sz phys %d\n", iRet,
 	          getLogicalQueueSize(pThis), getPhysicalQueueSize(pThis));
+
+	/* now we are done, but potentially need to re-aquire the mutex */
+	if(bNeedReLock)
+		d_pthread_mutex_lock(pThis->mut);
+
 	RETiRet;
 }