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 5AC6BC64EC7 for ; Mon, 13 Feb 2023 15:03:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231325AbjBMPC5 (ORCPT ); Mon, 13 Feb 2023 10:02:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34796 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231290AbjBMPCt (ORCPT ); Mon, 13 Feb 2023 10:02:49 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7BF681D920 for ; Mon, 13 Feb 2023 07:02:29 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 4C5A86112D for ; Mon, 13 Feb 2023 15:02:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 634A6C433EF; Mon, 13 Feb 2023 15:02:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1676300547; bh=R0lN8Z5FfDjyLf92iHh7nrJIb/VnR8+FkTh32q0ID8E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HS/zdCO6LaZ6lb3BrVgBop1cmhUlO8IgY3HYkmat76L4WjkdPb16Q/SqUoC8jYENo M3yf0NQ4CWQGx361WSM84LLNYwOQ/KYPCH0l7mp+R8/YQnuw8vG0fKs/zaMPK61nug z8JtWj570awlsZo4L9JaIdrWeyYCIEX4SuSCs8ks= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Magnus Karlsson , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10 038/139] qede: execute xdp_do_flush() before napi_complete_done() Date: Mon, 13 Feb 2023 15:49:43 +0100 Message-Id: <20230213144747.673274141@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230213144745.696901179@linuxfoundation.org> References: <20230213144745.696901179@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: Magnus Karlsson [ Upstream commit 2ccce20d51faa0178086163ccb6c84a099a87ab4 ] Make sure that xdp_do_flush() is always executed before napi_complete_done(). This is important for two reasons. First, a redirect to an XSKMAP assumes that a call to xdp_do_redirect() from napi context X on CPU Y will be followed by a xdp_do_flush() from the same napi context and CPU. This is not guaranteed if the napi_complete_done() is executed before xdp_do_flush(), as it tells the napi logic that it is fine to schedule napi context X on another CPU. Details from a production system triggering this bug using the veth driver can be found following the first link below. The second reason is that the XDP_REDIRECT logic in itself relies on being inside a single NAPI instance through to the xdp_do_flush() call for RCU protection of all in-kernel data structures. Details can be found in the second link below. Fixes: d1b25b79e162b ("qede: add .ndo_xdp_xmit() and XDP_REDIRECT support") Signed-off-by: Magnus Karlsson Acked-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/r/20221220185903.1105011-1-sbohrer@cloudflare.com Link: https://lore.kernel.org/all/20210624160609.292325-1-toke@redhat.com/ Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/qlogic/qede/qede_fp.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/qlogic/qede/qede_fp.c b/drivers/net/ethernet/qlogic/qede/qede_fp.c index 5b1885c0a8bd..a632de208a7d 100644 --- a/drivers/net/ethernet/qlogic/qede/qede_fp.c +++ b/drivers/net/ethernet/qlogic/qede/qede_fp.c @@ -1456,6 +1456,10 @@ int qede_poll(struct napi_struct *napi, int budget) rx_work_done = (likely(fp->type & QEDE_FASTPATH_RX) && qede_has_rx_work(fp->rxq)) ? qede_rx_int(fp, budget) : 0; + + if (fp->xdp_xmit & QEDE_XDP_REDIRECT) + xdp_do_flush(); + /* Handle case where we are called by netpoll with a budget of 0 */ if (rx_work_done < budget || !budget) { if (!qede_poll_is_more_work(fp)) { @@ -1475,9 +1479,6 @@ int qede_poll(struct napi_struct *napi, int budget) qede_update_tx_producer(fp->xdp_tx); } - if (fp->xdp_xmit & QEDE_XDP_REDIRECT) - xdp_do_flush_map(); - return rx_work_done; } -- 2.39.0