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Commit 71bdcf80 authored by Chuck Lever's avatar Chuck Lever Committed by Linus Torvalds
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[PATCH] SUNRPC: fix race in in-kernel RPC portmapper client 



When submitting a request to a fast portmapper (such as the local rpcbind
daemon), the request can complete before the parent task is even queued up on
xprt->binding.  Fix this by queuing before submitting the rpcbind request.

Test plan:
Connectathon locking test with UDP.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent b87c0adf

net/sunrpc/pmap_clnt.c

+7 −7
Original line number Diff line number Diff line
@@ -101,11 +101,13 @@ void rpc_getport(struct rpc_task *task) 
	/* Autobind on cloned rpc clients is discouraged */

	BUG_ON(clnt->cl_parent != clnt);



	if (xprt_test_and_set_binding(xprt)) {

		task->tk_status = -EACCES;	/* tell caller to check again */

	/* Put self on queue before sending rpcbind request, in case

	 * pmap_getport_done completes before we return from rpc_run_task */

	rpc_sleep_on(&xprt->binding, task, NULL, NULL);

		return;

	}



	status = -EACCES;		/* tell caller to check again */

	if (xprt_test_and_set_binding(xprt))

		goto bailout_nofree;



	/* Someone else may have bound if we slept */

	status = 0;
@@ -134,8 +136,6 @@ void rpc_getport(struct rpc_task *task) 
		goto bailout;

	rpc_release_task(child);



	rpc_sleep_on(&xprt->binding, task, NULL, NULL);



	task->tk_xprt->stat.bind_count++;

	return;