File 0011-The-shutdown-sequence-in-wtp-relies-for-its-operatio.patch of Package rsyslog.6132

From fae3e420f4e1da2b60400f4f06fdf41624e5fdf9 Mon Sep 17 00:00:00 2001
From: Tomas Sykora <tosykora@redhat.com>
Date: Thu, 24 Nov 2016 04:24:35 -0500
Subject: [PATCH] The shutdown sequence in wtp relies for its operation on
 signals and cancelation cleanup handlers. Previously, trying to shutdown a
 thread that has not yet been properly initialized could lead to a deadlock.
 This change makes wtpStartWrkr() synchronous in regard to the initialization
 of the newly created thread.

Thanks to Rado Sroka for the analysis and an initial patch.
---
 runtime/wtp.c | 13 +++++++++++++
 runtime/wtp.h |  1 +
 2 files changed, 14 insertions(+)

diff --git a/runtime/wtp.c b/runtime/wtp.c
index 7545080e..9b36c2e4 100644
--- a/runtime/wtp.c
+++ b/runtime/wtp.c
@@ -88,6 +88,7 @@ static rsRetVal NotImplementedDummy(void) { return RS_RET_NOT_IMPLEMENTED; }
  */
 BEGINobjConstruct(wtp) /* be sure to specify the object type also in END macro! */
 	pthread_mutex_init(&pThis->mutWtp, NULL);
+	pthread_cond_init(&pThis->condThrdInitDone, NULL);
 	pthread_cond_init(&pThis->condThrdTrm, NULL);
 	pthread_attr_init(&pThis->attrThrd);
 	/* Set thread scheduling policy to default */
@@ -156,6 +157,7 @@ CODESTARTobjDestruct(wtp)
 
 	/* actual destruction */
 	pthread_cond_destroy(&pThis->condThrdTrm);
+	pthread_cond_destroy(&pThis->condThrdInitDone);
 	pthread_mutex_destroy(&pThis->mutWtp);
 	pthread_attr_destroy(&pThis->attrThrd);
 	DESTROY_ATOMIC_HELPER_MUT(pThis->mutCurNumWrkThrd);
@@ -386,6 +388,12 @@ wtpWorker(void *arg) /* the arg is actually a wti object, even though we are in
 #	endif
 
 	pthread_cleanup_push(wtpWrkrExecCancelCleanup, pWti);
+
+        /* let the parent know we're done with initialization */
+        d_pthread_mutex_lock(&pThis->mutWtp);
+        pthread_cond_broadcast(&pThis->condThrdInitDone);
+        d_pthread_mutex_unlock(&pThis->mutWtp);
+
 	wtiWorker(pWti);
 	pthread_cleanup_pop(0);
 	wtpWrkrExecCleanup(pWti);
@@ -437,6 +445,11 @@ wtpStartWrkr(wtp_t *pThis)
 		  wtpGetDbgHdr(pThis), iState,
 		  ATOMIC_FETCH_32BIT(&pThis->iCurNumWrkThrd, &pThis->mutCurNumWrkThrd));
 
+        /* wait for the new thread to initialize its signal mask and
+         * cancelation cleanup handler before proceeding
+         */
+        d_pthread_cond_wait(&pThis->condThrdInitDone, &pThis->mutWtp);
+
 finalize_it:
 	d_pthread_mutex_unlock(&pThis->mutWtp);
 	RETiRet;
diff --git a/runtime/wtp.h b/runtime/wtp.h
index 95977f87..2ed6ae14 100644
--- a/runtime/wtp.h
+++ b/runtime/wtp.h
@@ -50,6 +50,7 @@ struct wtp_s {
 	rsRetVal (*pConsumer)(void *); /* user-supplied consumer function for dewtpd messages */
 	/* synchronization variables */
 	pthread_mutex_t mutWtp; /* mutex for the wtp's thread management */
+	pthread_cond_t condThrdInitDone; /* signalled when a new thread is ready for work */
 	pthread_cond_t condThrdTrm;/* signalled when threads terminate */
 	/* end sync variables */
 	/* user objects */
-- 
2.15.0