4.9-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 0a9a4304f3614e25d9de9b63502ca633c01c0d70 ]
If an asynchronous connection attempt completes while another task is in xprt_connect(), then the call to rpc_sleep_on() could end up racing with the call to xprt_wake_pending_tasks(). So add a second test of the connection state after we've put the task to sleep and set the XPRT_CONNECTING flag, when we know that there can be no asynchronous connection attempts still in progress.
Fixes: 0b9e79431377d ("SUNRPC: Move the test for XPRT_CONNECTING into...") Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/sunrpc/xprt.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 685e6d225414..1a8df242d26a 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -778,8 +778,15 @@ void xprt_connect(struct rpc_task *task) return; if (xprt_test_and_set_connecting(xprt)) return; - xprt->stat.connect_start = jiffies; - xprt->ops->connect(xprt, task); + /* Race breaker */ + if (!xprt_connected(xprt)) { + xprt->stat.connect_start = jiffies; + xprt->ops->connect(xprt, task); + } else { + xprt_clear_connecting(xprt); + task->tk_status = 0; + rpc_wake_up_queued_task(&xprt->pending, task); + } } xprt_release_write(xprt, task); }