diff options
| author | Trond Myklebust <trond.myklebust@primarydata.com> | 2017-12-14 21:24:08 -0500 |
|---|---|---|
| committer | Anna Schumaker <Anna.Schumaker@Netapp.com> | 2017-12-15 14:31:56 -0500 |
| commit | 90d91b0cd371193d9dbfa9beacab8ab9a4cb75e0 (patch) | |
| tree | b849c5a611ba70582e6e5612b25c6c00c612efaf | |
| parent | dc4fd9ab01ab379ae5af522b3efd4187a7c30a31 (diff) | |
| download | linux-90d91b0cd371193d9dbfa9beacab8ab9a4cb75e0.tar.gz linux-90d91b0cd371193d9dbfa9beacab8ab9a4cb75e0.tar.bz2 linux-90d91b0cd371193d9dbfa9beacab8ab9a4cb75e0.zip | |
SUNRPC: Fix a race in the receive code path
We must ensure that the call to rpc_sleep_on() in xprt_transmit() cannot
race with the call to xprt_complete_rqst().
Reported-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://bugzilla.linux-nfs.org/show_bug.cgi?id=317
Fixes: ce7c252a8c74 ("SUNRPC: Add a separate spinlock to protect..")
Cc: stable@vger.kernel.org # 4.14+
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
| -rw-r--r-- | net/sunrpc/xprt.c | 28 |
1 files changed, 19 insertions, 9 deletions
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 02a9bacb239b..5b06f6906a27 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -1001,6 +1001,7 @@ void xprt_transmit(struct rpc_task *task) { struct rpc_rqst *req = task->tk_rqstp; struct rpc_xprt *xprt = req->rq_xprt; + unsigned int connect_cookie; int status, numreqs; dprintk("RPC: %5u xprt_transmit(%u)\n", task->tk_pid, req->rq_slen); @@ -1024,6 +1025,7 @@ void xprt_transmit(struct rpc_task *task) } else if (!req->rq_bytes_sent) return; + connect_cookie = xprt->connect_cookie; req->rq_xtime = ktime_get(); status = xprt->ops->send_request(task); trace_xprt_transmit(xprt, req->rq_xid, status); @@ -1047,20 +1049,28 @@ void xprt_transmit(struct rpc_task *task) xprt->stat.bklog_u += xprt->backlog.qlen; xprt->stat.sending_u += xprt->sending.qlen; xprt->stat.pending_u += xprt->pending.qlen; + spin_unlock_bh(&xprt->transport_lock); - /* Don't race with disconnect */ - if (!xprt_connected(xprt)) - task->tk_status = -ENOTCONN; - else { + req->rq_connect_cookie = connect_cookie; + if (rpc_reply_expected(task) && !READ_ONCE(req->rq_reply_bytes_recvd)) { /* - * Sleep on the pending queue since - * we're expecting a reply. + * Sleep on the pending queue if we're expecting a reply. + * The spinlock ensures atomicity between the test of + * req->rq_reply_bytes_recvd, and the call to rpc_sleep_on(). */ - if (!req->rq_reply_bytes_recvd && rpc_reply_expected(task)) + spin_lock(&xprt->recv_lock); + if (!req->rq_reply_bytes_recvd) { rpc_sleep_on(&xprt->pending, task, xprt_timer); - req->rq_connect_cookie = xprt->connect_cookie; + /* + * Send an extra queue wakeup call if the + * connection was dropped in case the call to + * rpc_sleep_on() raced. + */ + if (!xprt_connected(xprt)) + xprt_wake_pending_tasks(xprt, -ENOTCONN); + } + spin_unlock(&xprt->recv_lock); } - spin_unlock_bh(&xprt->transport_lock); } static void xprt_add_backlog(struct rpc_xprt *xprt, struct rpc_task *task) |