From patchwork Mon Feb 22 12:36:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 386133 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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, 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 524B1C433DB for ; Mon, 22 Feb 2021 12:48:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 090BC64DF0 for ; Mon, 22 Feb 2021 12:48:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231500AbhBVMse (ORCPT ); Mon, 22 Feb 2021 07:48:34 -0500 Received: from mail.kernel.org ([198.145.29.99]:56552 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231650AbhBVMoj (ORCPT ); Mon, 22 Feb 2021 07:44:39 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2189464F51; Mon, 22 Feb 2021 12:41:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1613997685; bh=4HrBhgJIRgRPr9JuQrDIoTRdOmW5eiU2KLqhXKWskYc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tl8XckAYdtIdwDBwncsHrxppnaUnl90JwKJSkGP1ZEk7AplazOVvhKCHEQiePZXX6 wooF0JG5kSeqrnh7qu7AUD5f3zgQr7yjl63RSswDNRJ3A+mcGPeDIeL2+vzQjADWdQ p57P2X8kTf6/YXsf+HMYbXT74uegIhUcEnzaU4Ic= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Igor Druzhinin , Juergen Gross , Wei Liu , Jakub Kicinski , Sasha Levin Subject: [PATCH 4.9 26/49] xen/netback: avoid race in xenvif_rx_ring_slots_available() Date: Mon, 22 Feb 2021 13:36:24 +0100 Message-Id: <20210222121026.881460743@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210222121022.546148341@linuxfoundation.org> References: <20210222121022.546148341@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Juergen Gross [ Upstream commit ec7d8e7dd3a59528e305a18e93f1cb98f7faf83b ] Since commit 23025393dbeb3b8b3 ("xen/netback: use lateeoi irq binding") xenvif_rx_ring_slots_available() is no longer called only from the rx queue kernel thread, so it needs to access the rx queue with the associated queue held. Reported-by: Igor Druzhinin Fixes: 23025393dbeb3b8b3 ("xen/netback: use lateeoi irq binding") Signed-off-by: Juergen Gross Acked-by: Wei Liu Link: https://lore.kernel.org/r/20210202070938.7863-1-jgross@suse.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/xen-netback/rx.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c index f152246c7dfb7..ddfb1cfa2dd94 100644 --- a/drivers/net/xen-netback/rx.c +++ b/drivers/net/xen-netback/rx.c @@ -38,10 +38,15 @@ static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue) RING_IDX prod, cons; struct sk_buff *skb; int needed; + unsigned long flags; + + spin_lock_irqsave(&queue->rx_queue.lock, flags); skb = skb_peek(&queue->rx_queue); - if (!skb) + if (!skb) { + spin_unlock_irqrestore(&queue->rx_queue.lock, flags); return false; + } needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE); if (skb_is_gso(skb)) @@ -49,6 +54,8 @@ static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue) if (skb->sw_hash) needed++; + spin_unlock_irqrestore(&queue->rx_queue.lock, flags); + do { prod = queue->rx.sring->req_prod; cons = queue->rx.req_cons;