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Commit 168e4b39d1afb79a7e3ea6c3bb246b4c82c6bdb9

Authored by Weston Andros Adamson
Committed by Trond Myklebust
1 parent 3d70f8c617
Exists in smarc-l5.0.0_1.0.0-ga and in 5 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga

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>

Showing 1 changed file with 7 additions and 0 deletions Side-by-side Diff

... ... @@ -607,6 +607,13 @@
607 607 */
608 608 void rpc_shutdown_client(struct rpc_clnt *clnt)
609 609 {
  610 + /*
  611 + * To avoid deadlock, never call rpc_shutdown_client from a
  612 + * workqueue context!
  613 + */
  614 + WARN_ON_ONCE(current->flags & PF_WQ_WORKER);
  615 + might_sleep();
  616 +
610 617 dprintk_rcu("RPC: shutting down %s client for %s\n",
611 618 clnt->cl_protname,
612 619 rcu_dereference(clnt->cl_xprt)->servername);