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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 940DEC3276C for ; Thu, 2 Jan 2020 22:26:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5A2CE21835 for ; Thu, 2 Jan 2020 22:26:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578003973; bh=TTrH4AKxvepDzY/FRGVncaQTflBmRdZjrfprl3Qu84g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=IjJe82pXli3+J/ExwhyrxmhfbRPqQdI3/b85DyXy9WSa6yuXLbauvRnIBEDkfxQv0 fAIKTaKrAm283Y8TlX2+yhXtq7sc58D/bXbj24cAmnH/gNx7XZuXFLLW9yE5ayFe/x 6NbhyhaxwSFtbBsaG/WSHFlYbr+t96FCmOqYqJJI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729436AbgABW0M (ORCPT ); Thu, 2 Jan 2020 17:26:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:52964 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729617AbgABW0J (ORCPT ); Thu, 2 Jan 2020 17:26:09 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2EBB420863; Thu, 2 Jan 2020 22:26:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578003968; bh=TTrH4AKxvepDzY/FRGVncaQTflBmRdZjrfprl3Qu84g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BpEx7OZ14dH0GAQxHNbA8WtNZH4t+Xu/wIXcSx4wmZ8FjxAGymwZpXAlep8nqWmHg Fzfhx7Q4qK8I4qaXsYnvODW4XK4/UGzntsqqdyGhDvmC17GNC4f6v4R/BqW2bqYr9m /T0hTpAdtLf+FLM0+2O8wwidrZIQVCVzWqU6e4Ys= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Netanel Belgazal , "David S. Miller" Subject: [PATCH 4.14 74/91] net: ena: fix napi handler misbehavior when the napi budget is zero Date: Thu, 2 Jan 2020 23:07:56 +0100 Message-Id: <20200102220447.623164175@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200102220356.856162165@linuxfoundation.org> References: <20200102220356.856162165@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Netanel Belgazal [ Upstream commit 24dee0c7478d1a1e00abdf5625b7f921467325dc ] In netpoll the napi handler could be called with budget equal to zero. Current ENA napi handler doesn't take that into consideration. The napi handler handles Rx packets in a do-while loop. Currently, the budget check happens only after decrementing the budget, therefore the napi handler, in rare cases, could run over MAX_INT packets. In addition to that, this moves all budget related variables to int calculation and stop mixing u32 to avoid ambiguity Fixes: 1738cd3ed342 ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)") Signed-off-by: Netanel Belgazal Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/amazon/ena/ena_netdev.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c @@ -1196,8 +1196,8 @@ static int ena_io_poll(struct napi_struc struct ena_napi *ena_napi = container_of(napi, struct ena_napi, napi); struct ena_ring *tx_ring, *rx_ring; - u32 tx_work_done; - u32 rx_work_done; + int tx_work_done; + int rx_work_done = 0; int tx_budget; int napi_comp_call = 0; int ret; @@ -1214,7 +1214,11 @@ static int ena_io_poll(struct napi_struc } tx_work_done = ena_clean_tx_irq(tx_ring, tx_budget); - rx_work_done = ena_clean_rx_irq(rx_ring, napi, budget); + /* On netpoll the budget is zero and the handler should only clean the + * tx completions. + */ + if (likely(budget)) + rx_work_done = ena_clean_rx_irq(rx_ring, napi, budget); /* If the device is about to reset or down, avoid unmask * the interrupt and return 0 so NAPI won't reschedule