[libvirt] [PATCH v2 1/6] rpc: Fix deadlock if there is no worker pool available
@srv must be unlocked for the call virNetServerProcessMsg otherwise a
deadlock can occur.
Since the pointer 'srv->workers' will never be changed after
initialization and the thread pool has it's own locking we can release
the lock of 'srv' earlier. This also fixes the deadlock.
Signed-off-by: Marc Hartmayer <mhartmay(a)linux.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy(a)linux.ibm.com>
Reviewed-by: Bjoern Walk <bwalk(a)linux.ibm.com>
---
src/rpc/virnetserver.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/src/rpc/virnetserver.c b/src/rpc/virnetserver.c
index 5c7f7dd08fe1..091e3ef23406 100644
--- a/src/rpc/virnetserver.c
+++ b/src/rpc/virnetserver.c
@@ -51,6 +51,7 @@ struct _virNetServer {
char *name;
+ /* Immutable pointer, self-locking APIs */
virThreadPoolPtr workers;
char *mdnsGroupName;
@@ -177,9 +178,11 @@ static void virNetServerHandleJob(void *jobOpaque, void *opaque)
VIR_FREE(job);
}
-static void virNetServerDispatchNewMessage(virNetServerClientPtr client,
- virNetMessagePtr msg,
- void *opaque)
+
+static void
+virNetServerDispatchNewMessage(virNetServerClientPtr client,
+ virNetMessagePtr msg,
+ void *opaque)
{
virNetServerPtr srv = opaque;
virNetServerProgramPtr prog = NULL;
@@ -196,6 +199,9 @@ static void virNetServerDispatchNewMessage(virNetServerClientPtr
client,
break;
}
}
+ /* we can unlock @srv since @prog can only become invalid in case
+ * of disposing @srv */
+ virObjectUnlock(srv);
if (srv->workers) {
virNetServerJobPtr job;
@@ -223,15 +229,14 @@ static void virNetServerDispatchNewMessage(virNetServerClientPtr
client,
goto error;
}
- virObjectUnlock(srv);
return;
error:
virNetMessageFree(msg);
virNetServerClientClose(client);
- virObjectUnlock(srv);
}
+
/**
* virNetServerCheckLimits:
* @srv: server to check limits on
--
2.13.4