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| author | Chuck Lever <chuck.lever@oracle.com> | 2020-06-27 12:35:09 -0400 |
|---|---|---|
| committer | Anna Schumaker <Anna.Schumaker@Netapp.com> | 2020-07-13 10:50:41 -0400 |
| commit | 4cf44be6f1e86da302085bf3e1dc2c86f3cdaaaa (patch) | |
| tree | 272261fd0bd0b64b7468338f9cb512656f71f172 /net/sunrpc | |
| parent | 85bfd71bc34e20d9fadb745131f6314c36d0f75b (diff) | |
| download | lwn-4cf44be6f1e86da302085bf3e1dc2c86f3cdaaaa.tar.gz lwn-4cf44be6f1e86da302085bf3e1dc2c86f3cdaaaa.zip | |
xprtrdma: Fix recursion into rpcrdma_xprt_disconnect()
Both Dan and I have observed two processes invoking
rpcrdma_xprt_disconnect() concurrently. In my case:
1. The connect worker invokes rpcrdma_xprt_disconnect(), which
drains the QP and waits for the final completion
2. This causes the newly posted Receive to flush and invoke
xprt_force_disconnect()
3. xprt_force_disconnect() sets CLOSE_WAIT and wakes up the RPC task
that is holding the transport lock
4. The RPC task invokes xprt_connect(), which calls ->ops->close
5. xprt_rdma_close() invokes rpcrdma_xprt_disconnect(), which tries
to destroy the QP.
Deadlock.
To prevent xprt_force_disconnect() from waking anything, handle the
clean up after a failed connection attempt in the xprt's sndtask.
The retry loop is removed from rpcrdma_xprt_connect() to ensure
that the newly allocated ep and id are properly released before
a REJECTED connection attempt can be retried.
Reported-by: Dan Aloni <dan@kernelim.com>
Fixes: e28ce90083f0 ("xprtrdma: kmalloc rpcrdma_ep separate from rpcrdma_xprt")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Diffstat (limited to 'net/sunrpc')
| -rw-r--r-- | net/sunrpc/xprtrdma/transport.c | 5 | ||||
| -rw-r--r-- | net/sunrpc/xprtrdma/verbs.c | 10 |
2 files changed, 7 insertions, 8 deletions
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c index 14165b673b20..053c8ab1265a 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -249,6 +249,11 @@ xprt_rdma_connect_worker(struct work_struct *work) xprt->stat.connect_start; xprt_set_connected(xprt); rc = -EAGAIN; + } else { + /* Force a call to xprt_rdma_close to clean up */ + spin_lock(&xprt->transport_lock); + set_bit(XPRT_CLOSE_WAIT, &xprt->state); + spin_unlock(&xprt->transport_lock); } xprt_wake_pending_tasks(xprt, rc); } diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index e4c0df7c7d78..641a3ca0fc8f 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -290,7 +290,7 @@ rpcrdma_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event) sap, rdma_reject_msg(id, event->status)); ep->re_connect_status = -ECONNREFUSED; if (event->status == IB_CM_REJ_STALE_CONN) - ep->re_connect_status = -EAGAIN; + ep->re_connect_status = -ENOTCONN; goto disconnected; case RDMA_CM_EVENT_DISCONNECTED: ep->re_connect_status = -ECONNABORTED; @@ -521,8 +521,6 @@ int rpcrdma_xprt_connect(struct rpcrdma_xprt *r_xprt) struct rpcrdma_ep *ep; int rc; -retry: - rpcrdma_xprt_disconnect(r_xprt); rc = rpcrdma_ep_create(r_xprt); if (rc) return rc; @@ -550,17 +548,13 @@ retry: wait_event_interruptible(ep->re_connect_wait, ep->re_connect_status != 0); if (ep->re_connect_status <= 0) { - if (ep->re_connect_status == -EAGAIN) - goto retry; rc = ep->re_connect_status; goto out; } rc = rpcrdma_reqs_setup(r_xprt); - if (rc) { - rpcrdma_xprt_disconnect(r_xprt); + if (rc) goto out; - } rpcrdma_mrs_create(r_xprt); out: |