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=-9.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 678E0C43381 for ; Sat, 23 Feb 2019 21:05:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3328520861 for ; Sat, 23 Feb 2019 21:05:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550955944; bh=lek0c7COj/ge+DS9x6ftwTzXTykH0htF8WMlWU0NB1c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Ku1f1jQ8AmDzqJrfusWXXmaNhCzxgJDFrqliVSjnt6tAGKgf47RCskUh11X0awE3t qkJ6Ou/JA/3YiYOpx8No6z0yktuiqRrrpe+SwtGnWHFcG6n/xnTzLiU0tph+WjBSwF 73c2W/rI5mPeEHG5Qg9XPrJ1js1Sd72JfSDIHhso= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728495AbfBWVFn (ORCPT ); Sat, 23 Feb 2019 16:05:43 -0500 Received: from mail.kernel.org ([198.145.29.99]:40792 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728455AbfBWVFj (ORCPT ); Sat, 23 Feb 2019 16:05:39 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6E01C20657; Sat, 23 Feb 2019 21:05:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550955938; bh=lek0c7COj/ge+DS9x6ftwTzXTykH0htF8WMlWU0NB1c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AoKvAed1Mk0Cl7orCbxS28Z196AZitsfwm4Yy+bUB6Ztl5rs3B1cdmb55t0Z5fpWB 1+auyYsSPZgiCHR5mejtEkNCc2KCbUcQMsz95OU3C+T0VmQXIY/tlLgScU7DLZlxys gfF6LNBuDg+RQ2xt+bYqnnwB5k8M+PHgjgGYWiTs= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Manish Chopra , Ariel Elior , "David S . Miller" , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.20 46/72] qed: Fix system crash in ll2 xmit Date: Sat, 23 Feb 2019 16:03:56 -0500 Message-Id: <20190223210422.199966-46-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190223210422.199966-1-sashal@kernel.org> References: <20190223210422.199966-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Manish Chopra [ Upstream commit 7c81626a3c37e4ac320b8ad785694ba498f24794 ] Cache number of fragments in the skb locally as in case of linear skb (with zero fragments), tx completion (or freeing of skb) may happen before driver tries to get number of frgaments from the skb which could lead to stale access to an already freed skb. Signed-off-by: Manish Chopra Signed-off-by: Ariel Elior Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/qlogic/qed/qed_ll2.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/qlogic/qed/qed_ll2.c b/drivers/net/ethernet/qlogic/qed/qed_ll2.c index c6f4bab67a5fc..6d4bd6e12cf76 100644 --- a/drivers/net/ethernet/qlogic/qed/qed_ll2.c +++ b/drivers/net/ethernet/qlogic/qed/qed_ll2.c @@ -2437,19 +2437,24 @@ static int qed_ll2_start_xmit(struct qed_dev *cdev, struct sk_buff *skb, { struct qed_ll2_tx_pkt_info pkt; const skb_frag_t *frag; + u8 flags = 0, nr_frags; int rc = -EINVAL, i; dma_addr_t mapping; u16 vlan = 0; - u8 flags = 0; if (unlikely(skb->ip_summed != CHECKSUM_NONE)) { DP_INFO(cdev, "Cannot transmit a checksummed packet\n"); return -EINVAL; } - if (1 + skb_shinfo(skb)->nr_frags > CORE_LL2_TX_MAX_BDS_PER_PACKET) { + /* Cache number of fragments from SKB since SKB may be freed by + * the completion routine after calling qed_ll2_prepare_tx_packet() + */ + nr_frags = skb_shinfo(skb)->nr_frags; + + if (1 + nr_frags > CORE_LL2_TX_MAX_BDS_PER_PACKET) { DP_ERR(cdev, "Cannot transmit a packet with %d fragments\n", - 1 + skb_shinfo(skb)->nr_frags); + 1 + nr_frags); return -EINVAL; } @@ -2471,7 +2476,7 @@ static int qed_ll2_start_xmit(struct qed_dev *cdev, struct sk_buff *skb, } memset(&pkt, 0, sizeof(pkt)); - pkt.num_of_bds = 1 + skb_shinfo(skb)->nr_frags; + pkt.num_of_bds = 1 + nr_frags; pkt.vlan = vlan; pkt.bd_flags = flags; pkt.tx_dest = QED_LL2_TX_DEST_NW; @@ -2482,12 +2487,17 @@ static int qed_ll2_start_xmit(struct qed_dev *cdev, struct sk_buff *skb, test_bit(QED_LL2_XMIT_FLAGS_FIP_DISCOVERY, &xmit_flags)) pkt.remove_stag = true; + /* qed_ll2_prepare_tx_packet() may actually send the packet if + * there are no fragments in the skb and subsequently the completion + * routine may run and free the SKB, so no dereferencing the SKB + * beyond this point unless skb has any fragments. + */ rc = qed_ll2_prepare_tx_packet(&cdev->hwfns[0], cdev->ll2->handle, &pkt, 1); if (rc) goto err; - for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + for (i = 0; i < nr_frags; i++) { frag = &skb_shinfo(skb)->frags[i]; mapping = skb_frag_dma_map(&cdev->pdev->dev, frag, 0, -- 2.19.1