From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75F77C48BDE for ; Sun, 7 Jul 2019 19:41:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5935520651 for ; Sun, 7 Jul 2019 19:41:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728090AbfGGTlM (ORCPT ); Sun, 7 Jul 2019 15:41:12 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:57892 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727656AbfGGTiP (ORCPT ); Sun, 7 Jul 2019 15:38:15 -0400 Received: from 94.197.121.43.threembb.co.uk ([94.197.121.43] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hkCzD-0006kK-CH; Sun, 07 Jul 2019 20:38:11 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hkCz9-0005fs-0Y; Sun, 07 Jul 2019 20:38:07 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Tariq Toukan" , "Jack Morgenstein" , "David S. Miller" Date: Sun, 07 Jul 2019 17:54:17 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 117/129] net/mlx4_core: Fix locking in SRIOV mode when switching between events and polling In-Reply-To: X-SA-Exim-Connect-IP: 94.197.121.43 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.70-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jack Morgenstein commit c07d27927f2f2e96fcd27bb9fb330c9ea65612d0 upstream. In procedures mlx4_cmd_use_events() and mlx4_cmd_use_polling(), we need to guarantee that there are no FW commands in progress on the comm channel (for VFs) or wrapped FW commands (on the PF) when SRIOV is active. We do this by also taking the slave_cmd_mutex when SRIOV is active. This is especially important when switching from event to polling, since we free the command-context array during the switch. If there are FW commands in progress (e.g., waiting for a completion event), the completion event handler will access freed memory. Since the decision to use comm_wait or comm_poll is taken before grabbing the event_sem/poll_sem in mlx4_comm_cmd_wait/poll, we must take the slave_cmd_mutex as well (to guarantee that the decision to use events or polling and the call to the appropriate cmd function are atomic). Fixes: a7e1f04905e5 ("net/mlx4_core: Fix deadlock when switching between polling and event fw commands") Signed-off-by: Jack Morgenstein Signed-off-by: Tariq Toukan Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- drivers/net/ethernet/mellanox/mlx4/cmd.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/drivers/net/ethernet/mellanox/mlx4/cmd.c +++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c @@ -2196,6 +2196,8 @@ int mlx4_cmd_use_events(struct mlx4_dev if (!priv->cmd.context) return -ENOMEM; + if (mlx4_is_mfunc(dev)) + mutex_lock(&priv->cmd.slave_cmd_mutex); down_write(&priv->cmd.switch_sem); for (i = 0; i < priv->cmd.max_cmds; ++i) { priv->cmd.context[i].token = i; @@ -2217,6 +2219,8 @@ int mlx4_cmd_use_events(struct mlx4_dev down(&priv->cmd.poll_sem); priv->cmd.use_events = 1; up_write(&priv->cmd.switch_sem); + if (mlx4_is_mfunc(dev)) + mutex_unlock(&priv->cmd.slave_cmd_mutex); return err; } @@ -2229,6 +2233,8 @@ void mlx4_cmd_use_polling(struct mlx4_de struct mlx4_priv *priv = mlx4_priv(dev); int i; + if (mlx4_is_mfunc(dev)) + mutex_lock(&priv->cmd.slave_cmd_mutex); down_write(&priv->cmd.switch_sem); priv->cmd.use_events = 0; @@ -2239,6 +2245,8 @@ void mlx4_cmd_use_polling(struct mlx4_de up(&priv->cmd.poll_sem); up_write(&priv->cmd.switch_sem); + if (mlx4_is_mfunc(dev)) + mutex_unlock(&priv->cmd.slave_cmd_mutex); } struct mlx4_cmd_mailbox *mlx4_alloc_cmd_mailbox(struct mlx4_dev *dev)