From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Tue, 21 May 2013 03:00:18 +0000 (-0400)
Subject: SUNRPC: Fix a potential race in rpc_execute
X-Git-Tag: firefly_0821_release~176^2~5759^2~30
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a76580fbf09e6e19c2040c08969af5137e064eda;p=firefly-linux-kernel-4.4.55.git

SUNRPC: Fix a potential race in rpc_execute

If the rpc_task is asynchronous, it could theoretically finish executing
on the workqueue it was assigned by rpc_make_runnable() before we get
round to testing RPC_IS_ASYNC() in rpc_execute.

In practice, however, all the existing callers hold a reference to the
rpc_task, so this can't happen today...

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 5356b120dbf8..849ca413522c 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -825,9 +825,11 @@ static void __rpc_execute(struct rpc_task *task)
  */
 void rpc_execute(struct rpc_task *task)
 {
+	bool is_async = RPC_IS_ASYNC(task);
+
 	rpc_set_active(task);
 	rpc_make_runnable(task);
-	if (!RPC_IS_ASYNC(task))
+	if (!is_async)
 		__rpc_execute(task);
 }