linux-kernel - [PATCH 4.16 032/161] qed: Fix LL2 race during connection terminate

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Date:   Thu, 24 May 2018 11:37:37 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Ariel Elior <Ariel.Elior@...ium.com>,
        Michal Kalderon <Michal.Kalderon@...ium.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH 4.16 032/161] qed: Fix LL2 race during connection terminate

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

------------------

From: Michal Kalderon <Michal.Kalderon@...ium.com>

[ Upstream commit 490068deaef0c76e47bf89c457de899b7d3995c7 ]

Stress on qedi/qedr load unload lead to list_del corruption.
This is due to ll2 connection terminate freeing resources without
verifying that no more ll2 processing will occur.

This patch unregisters the ll2 status block before terminating
the connection to assure this race does not occur.

Fixes: 1d6cff4fca4366 ("qed: Add iSCSI out of order packet handling")
Signed-off-by: Ariel Elior <Ariel.Elior@...ium.com>
Signed-off-by: Michal Kalderon <Michal.Kalderon@...ium.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/net/ethernet/qlogic/qed/qed_ll2.c |   24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

--- a/drivers/net/ethernet/qlogic/qed/qed_ll2.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_ll2.c
@@ -842,6 +842,9 @@ static int qed_ll2_lb_rxq_completion(str
 	struct qed_ll2_info *p_ll2_conn = (struct qed_ll2_info *)p_cookie;
 	int rc;
 
+	if (!QED_LL2_RX_REGISTERED(p_ll2_conn))
+		return 0;
+
 	rc = qed_ll2_lb_rxq_handler(p_hwfn, p_ll2_conn);
 	if (rc)
 		return rc;
@@ -862,6 +865,9 @@ static int qed_ll2_lb_txq_completion(str
 	u16 new_idx = 0, num_bds = 0;
 	int rc;
 
+	if (!QED_LL2_TX_REGISTERED(p_ll2_conn))
+		return 0;
+
 	new_idx = le16_to_cpu(*p_tx->p_fw_cons);
 	num_bds = ((s16)new_idx - (s16)p_tx->bds_idx);
 
@@ -1915,17 +1921,25 @@ int qed_ll2_terminate_connection(void *c
 
 	/* Stop Tx & Rx of connection, if needed */
 	if (QED_LL2_TX_REGISTERED(p_ll2_conn)) {
+		p_ll2_conn->tx_queue.b_cb_registred = false;
+		smp_wmb(); /* Make sure this is seen by ll2_lb_rxq_completion */
 		rc = qed_sp_ll2_tx_queue_stop(p_hwfn, p_ll2_conn);
 		if (rc)
 			goto out;
+
 		qed_ll2_txq_flush(p_hwfn, connection_handle);
+		qed_int_unregister_cb(p_hwfn, p_ll2_conn->tx_queue.tx_sb_index);
 	}
 
 	if (QED_LL2_RX_REGISTERED(p_ll2_conn)) {
+		p_ll2_conn->rx_queue.b_cb_registred = false;
+		smp_wmb(); /* Make sure this is seen by ll2_lb_rxq_completion */
 		rc = qed_sp_ll2_rx_queue_stop(p_hwfn, p_ll2_conn);
 		if (rc)
 			goto out;
+
 		qed_ll2_rxq_flush(p_hwfn, connection_handle);
+		qed_int_unregister_cb(p_hwfn, p_ll2_conn->rx_queue.rx_sb_index);
 	}
 
 	if (p_ll2_conn->input.conn_type == QED_LL2_TYPE_OOO)
@@ -1973,16 +1987,6 @@ void qed_ll2_release_connection(void *cx
 	if (!p_ll2_conn)
 		return;
 
-	if (QED_LL2_RX_REGISTERED(p_ll2_conn)) {
-		p_ll2_conn->rx_queue.b_cb_registred = false;
-		qed_int_unregister_cb(p_hwfn, p_ll2_conn->rx_queue.rx_sb_index);
-	}
-
-	if (QED_LL2_TX_REGISTERED(p_ll2_conn)) {
-		p_ll2_conn->tx_queue.b_cb_registred = false;
-		qed_int_unregister_cb(p_hwfn, p_ll2_conn->tx_queue.tx_sb_index);
-	}
-
 	kfree(p_ll2_conn->tx_queue.descq_mem);
 	qed_chain_free(p_hwfn->cdev, &p_ll2_conn->tx_queue.txq_chain);