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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF788C4167B for ; Mon, 12 Dec 2022 13:43:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232671AbiLLNnK (ORCPT ); Mon, 12 Dec 2022 08:43:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232708AbiLLNms (ORCPT ); Mon, 12 Dec 2022 08:42:48 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 36B58614D for ; Mon, 12 Dec 2022 05:41:35 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id DE148B80D4F for ; Mon, 12 Dec 2022 13:41:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A9A3C433D2; Mon, 12 Dec 2022 13:41:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1670852492; bh=UlQIcF4anpMd3SXMOJR9lMJ5nuI4m1Q6Q73lBoy8zfY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2Cfm8HJoDuznTsiyzr4hBNxlkxmlx0xLJ9BkxV2h9hV7kpPgE8+3FxHHhQI3DPy08 G7AUtucmNM2lW0oGHTMTGv7xaeoHUuSThL8qBdhquRwgZqISvW6Rj6JwFrfqJTTIma xUQVgOVDeq6Hivm002M5QxfuK+C/cRTi4/Vh3KZk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Haiyang Zhang , Paolo Abeni Subject: [PATCH 6.0 065/157] net: mana: Fix race on per-CQ variable napi work_done Date: Mon, 12 Dec 2022 14:16:53 +0100 Message-Id: <20221212130937.188521672@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221212130934.337225088@linuxfoundation.org> References: <20221212130934.337225088@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Haiyang Zhang commit 18010ff776fa42340efc428b3ea6d19b3e7c7b21 upstream. After calling napi_complete_done(), the NAPIF_STATE_SCHED bit may be cleared, and another CPU can start napi thread and access per-CQ variable, cq->work_done. If the other thread (for example, from busy_poll) sets it to a value >= budget, this thread will continue to run when it should stop, and cause memory corruption and panic. To fix this issue, save the per-CQ work_done variable in a local variable before napi_complete_done(), so it won't be corrupted by a possible concurrent thread after napi_complete_done(). Also, add a flag bit to advertise to the NIC firmware: the NAPI work_done variable race is fixed, so the driver is able to reliably support features like busy_poll. Cc: stable@vger.kernel.org Fixes: e1b5683ff62e ("net: mana: Move NAPI from EQ to CQ") Signed-off-by: Haiyang Zhang Link: https://lore.kernel.org/r/1670010190-28595-1-git-send-email-haiyangz@microsoft.com Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/microsoft/mana/gdma.h | 9 ++++++++- drivers/net/ethernet/microsoft/mana/mana_en.c | 16 +++++++++++----- 2 files changed, 19 insertions(+), 6 deletions(-) --- a/drivers/net/ethernet/microsoft/mana/gdma.h +++ b/drivers/net/ethernet/microsoft/mana/gdma.h @@ -498,7 +498,14 @@ enum { #define GDMA_DRV_CAP_FLAG_1_EQ_SHARING_MULTI_VPORT BIT(0) -#define GDMA_DRV_CAP_FLAGS1 GDMA_DRV_CAP_FLAG_1_EQ_SHARING_MULTI_VPORT +/* Advertise to the NIC firmware: the NAPI work_done variable race is fixed, + * so the driver is able to reliably support features like busy_poll. + */ +#define GDMA_DRV_CAP_FLAG_1_NAPI_WKDONE_FIX BIT(2) + +#define GDMA_DRV_CAP_FLAGS1 \ + (GDMA_DRV_CAP_FLAG_1_EQ_SHARING_MULTI_VPORT | \ + GDMA_DRV_CAP_FLAG_1_NAPI_WKDONE_FIX) #define GDMA_DRV_CAP_FLAGS2 0 --- a/drivers/net/ethernet/microsoft/mana/mana_en.c +++ b/drivers/net/ethernet/microsoft/mana/mana_en.c @@ -1303,10 +1303,11 @@ static void mana_poll_rx_cq(struct mana_ xdp_do_flush(); } -static void mana_cq_handler(void *context, struct gdma_queue *gdma_queue) +static int mana_cq_handler(void *context, struct gdma_queue *gdma_queue) { struct mana_cq *cq = context; u8 arm_bit; + int w; WARN_ON_ONCE(cq->gdma_cq != gdma_queue); @@ -1315,26 +1316,31 @@ static void mana_cq_handler(void *contex else mana_poll_tx_cq(cq); - if (cq->work_done < cq->budget && - napi_complete_done(&cq->napi, cq->work_done)) { + w = cq->work_done; + + if (w < cq->budget && + napi_complete_done(&cq->napi, w)) { arm_bit = SET_ARM_BIT; } else { arm_bit = 0; } mana_gd_ring_cq(gdma_queue, arm_bit); + + return w; } static int mana_poll(struct napi_struct *napi, int budget) { struct mana_cq *cq = container_of(napi, struct mana_cq, napi); + int w; cq->work_done = 0; cq->budget = budget; - mana_cq_handler(cq, cq->gdma_cq); + w = mana_cq_handler(cq, cq->gdma_cq); - return min(cq->work_done, budget); + return min(w, budget); } static void mana_schedule_napi(void *context, struct gdma_queue *gdma_queue)