From 168e4b39d1afb79a7e3ea6c3bb246b4c82c6bdb9 Mon Sep 17 00:00:00 2001 From: Weston Andros Adamson Date: Tue, 30 Oct 2012 17:01:40 -0400 Subject: [PATCH] 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 Signed-off-by: Trond Myklebust --- net/sunrpc/clnt.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index cdc7564b4512..dd2532c10324 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -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); -- 2.39.2