[PATCH 4.7 68/69] iw_cxgb4: stop MPA_REPLY timer when disconnecting

From: Greg Kroah-Hartman
Date: Wed Sep 28 2016 - 05:17:20 EST

4.7-stable review patch. If anyone has any objections, please let me know.


From: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx>

commit 12eb5137edecfd8fb6d23dacec2a3630e729736f upstream.

There exists a race where the application can setup a connection
and then disconnect it before iw_cxgb4 processes the fw4_ack
message. For passive side connections, the fw4_ack message is
used to know when to stop the ep timer for MPA_REPLY messages.

If the application disconnects before the fw4_ack is handled then
c4iw_ep_disconnect() needs to clean up the timer state and stop the
timer before restarting it for the disconnect timer. Failure to do this
results in a "timer already started" message and a premature stopping
of the disconnect timer.

Fixes: e4b76a2 ("RDMA/iw_cxgb4: stop_ep_timer() after MPA negotiation")

Signed-off-by: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/infiniband/hw/cxgb4/cm.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c
@@ -3011,9 +3011,9 @@ static int fw4_ack(struct c4iw_dev *dev,
PDBG("%s last streaming msg ack ep %p tid %u state %u "
"initiator %u freeing skb\n", __func__, ep, ep->hwtid,
state_read(&ep->com), ep->mpa_attr.initiator ? 1 : 0);
+ mutex_lock(&ep->com.mutex);
ep->mpa_skb = NULL;
- mutex_lock(&ep->com.mutex);
if (test_bit(STOP_MPA_TIMER, &ep->com.flags))
@@ -3582,6 +3582,16 @@ int c4iw_ep_disconnect(struct c4iw_ep *e
ep->com.state = ABORTING;
else {
ep->com.state = CLOSING;
+ /*
+ * if we close before we see the fw4_ack() then we fix
+ * up the timer state since we're reusing it.
+ */
+ if (ep->mpa_skb &&
+ test_bit(STOP_MPA_TIMER, &ep->com.flags)) {
+ clear_bit(STOP_MPA_TIMER, &ep->com.flags);
+ stop_ep_timer(ep);
+ }
set_bit(CLOSE_SENT, &ep->com.flags);