From: Krishnamraju Eraparaju krishna2@chelsio.com
commit d219face9059f38ad187bde133451a2a308fdb7c upstream.
As per draft-hilland-iwarp-verbs-v1.0, sec 6.2.3, always initiate a CLOSE when entering into TERM state.
In c4iw_modify_qp(), disconnect operation should only be performed when the modify_qp call is invoked from ib_core. And all other internal modify_qp calls(invoked within iw_cxgb4) that needs 'disconnect' should call c4iw_ep_disconnect() explicitly after modify_qp. Otherwise, deadlocks like below can occur:
Call Trace: schedule+0x2f/0xa0 schedule_preempt_disabled+0xa/0x10 __mutex_lock.isra.5+0x2d0/0x4a0 c4iw_ep_disconnect+0x39/0x430 => tries to reacquire ep lock again c4iw_modify_qp+0x468/0x10d0 rx_data+0x218/0x570 => acquires ep lock process_work+0x5f/0x70 process_one_work+0x1a7/0x3b0 worker_thread+0x30/0x390 kthread+0x112/0x130 ret_from_fork+0x35/0x40
Fixes: d2c33370ae73 ("RDMA/iw_cxgb4: Always disconnect when QP is transitioning to TERMINATE state") Link: https://lore.kernel.org/r/20200204091230.7210-1-krishna2@chelsio.com Signed-off-by: Krishnamraju Eraparaju krishna2@chelsio.com Signed-off-by: Jason Gunthorpe jgg@mellanox.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/infiniband/hw/cxgb4/cm.c | 4 ++++ drivers/infiniband/hw/cxgb4/qp.c | 4 ++-- 2 files changed, 6 insertions(+), 2 deletions(-)
--- a/drivers/infiniband/hw/cxgb4/cm.c +++ b/drivers/infiniband/hw/cxgb4/cm.c @@ -3036,6 +3036,10 @@ static int terminate(struct c4iw_dev *de C4IW_QP_ATTR_NEXT_STATE, &attrs, 1); }
+ /* As per draft-hilland-iwarp-verbs-v1.0, sec 6.2.3, + * when entering the TERM state the RNIC MUST initiate a CLOSE. + */ + c4iw_ep_disconnect(ep, 1, GFP_KERNEL); c4iw_put_ep(&ep->com); } else pr_warn("TERM received tid %u no ep/qp\n", tid); --- a/drivers/infiniband/hw/cxgb4/qp.c +++ b/drivers/infiniband/hw/cxgb4/qp.c @@ -1948,10 +1948,10 @@ int c4iw_modify_qp(struct c4iw_dev *rhp, qhp->attr.layer_etype = attrs->layer_etype; qhp->attr.ecode = attrs->ecode; ep = qhp->ep; - c4iw_get_ep(&ep->com); - disconnect = 1; if (!internal) { + c4iw_get_ep(&ep->com); terminate = 1; + disconnect = 1; } else { terminate = qhp->attr.send_term; ret = rdma_fini(rhp, qhp, ep);