From patchwork Tue Feb 2 07:09:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Juergen Gross X-Patchwork-Id: 375049 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=-18.7 required=3.0 tests=BAYES_00,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=unavailable 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 932CDC433E0 for ; Tue, 2 Feb 2021 07:10:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6230664EDF for ; Tue, 2 Feb 2021 07:10:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232018AbhBBHKg (ORCPT ); Tue, 2 Feb 2021 02:10:36 -0500 Received: from mx2.suse.de ([195.135.220.15]:58388 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231158AbhBBHK2 (ORCPT ); Tue, 2 Feb 2021 02:10:28 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1612249781; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=1tpaqvOitmoTdUOKCltTkXQMrQMduhfR/V/K0TJ91jk=; b=pbaIptIDBcZvfobat6HNoXje6mR3kf8+MuWpibPjXaHBmoQvt3LBZ1S4k+WfN+6v3yXqqG CnLh7G8uXWy5d/2yQhTslehE4QmbeheYR1UmRM7pfxMgd1ZiuvafUH6s9i4k7bnpbVZHHm wGiaWxu3itzFTHNe0z01xg0UqKte3eQ= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 46D2EACB7; Tue, 2 Feb 2021 07:09:41 +0000 (UTC) From: Juergen Gross To: xen-devel@lists.xenproject.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Juergen Gross , Wei Liu , Paul Durrant , "David S. Miller" , Jakub Kicinski , Igor Druzhinin , stable@vger.kernel.org Subject: [PATCH] xen/netback: avoid race in xenvif_rx_ring_slots_available() Date: Tue, 2 Feb 2021 08:09:38 +0100 Message-Id: <20210202070938.7863-1-jgross@suse.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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") Cc: stable@vger.kernel.org Signed-off-by: Juergen Gross --- 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 b8febe1d1bfd..accc991d153f 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;