Commit 168e4b39 authored Oct 30, 2012 by Weston Andros Adamson Committed by Trond Myklebust Nov 04, 2012

SUNRPC: add WARN_ON_ONCE for potential deadlock

rpc_shutdown_client should never be called from a workqueue context.
If it is, it could deadlock looping forever trying to kill tasks that are
assigned to the same kworker thread (and will never run rpc_exit_task).

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

parent 3d70f8c6

net/sunrpc/clnt.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -607,6 +607,13 @@ EXPORT_SYMBOL_GPL(rpc_killall_tasks);
		*/
		void rpc_shutdown_client(struct rpc_clnt *clnt)
		{
		/*
		* To avoid deadlock, never call rpc_shutdown_client from a
		* workqueue context!
		*/
		WARN_ON_ONCE(current->flags & PF_WQ_WORKER);
		might_sleep();

		dprintk_rcu("RPC: shutting down %s client for %s\n",
		clnt->cl_protname,
		rcu_dereference(clnt->cl_xprt)->servername);