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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 E35A3C4742C for ; Tue, 3 Nov 2020 20:54:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 98A84223BF for ; Tue, 3 Nov 2020 20:54:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604436890; bh=FsuqPvptEOh9bnEUCkAE4VHhg7XcmMiOvu/IENmUCe4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=LZ0lUV5d5fSC7HS7SoijtEyRUO8J/3WQDTBTdCvtDIyyIgvQk24Hv5cEkfy2zY/Xq 1zOtebUI5ORd9dRw6un4bGfqOiOHIDn09h+liq+oXnV9W3HTisge8G8bHJu2OApNj4 FZJKKCBpX2DwDXd6pdD9OVcZvYR1KFN5u+eyZeIw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732586AbgKCUyt (ORCPT ); Tue, 3 Nov 2020 15:54:49 -0500 Received: from mail.kernel.org ([198.145.29.99]:54298 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731955AbgKCUys (ORCPT ); Tue, 3 Nov 2020 15:54:48 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 626B72053B; Tue, 3 Nov 2020 20:54:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604436887; bh=FsuqPvptEOh9bnEUCkAE4VHhg7XcmMiOvu/IENmUCe4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2BKFjAtnsyK0PDwezJO9uIHfJj9hRD1PDdWuBDSd3srboRLNbZOF1ZhTNTfpU6n6W niKhNogynArYPNXKPCkYoKjL2xld+/3T/7LryNwZ5dyq7Rr2W5t0YeuGkggb929mj5 PxnzYKrolF9vvE2gnkDT36ng1WKaVQDar9yPQUPs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Magnus Karlsson , Alexei Starovoitov , Sasha Levin Subject: [PATCH 5.4 054/214] samples/bpf: Fix possible deadlock in xdpsock Date: Tue, 3 Nov 2020 21:35:02 +0100 Message-Id: <20201103203255.318895565@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201103203249.448706377@linuxfoundation.org> References: <20201103203249.448706377@linuxfoundation.org> User-Agent: quilt/0.66 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 5a2a0dd88f0f267ac5953acd81050ae43a82201f ] Fix a possible deadlock in the l2fwd application in xdpsock that can occur when there is no space in the Tx ring. There are two ways to get the kernel to consume entries in the Tx ring: calling sendto() to make it send packets and freeing entries from the completion ring, as the kernel will not send a packet if there is no space for it to add a completion entry in the completion ring. The Tx loop in l2fwd only used to call sendto(). This patches adds cleaning the completion ring in that loop. Signed-off-by: Magnus Karlsson Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/1599726666-8431-3-git-send-email-magnus.karlsson@gmail.com Signed-off-by: Sasha Levin --- samples/bpf/xdpsock_user.c | 1 + 1 file changed, 1 insertion(+) diff --git a/samples/bpf/xdpsock_user.c b/samples/bpf/xdpsock_user.c index df011ac334022..79d1005ff2ee3 100644 --- a/samples/bpf/xdpsock_user.c +++ b/samples/bpf/xdpsock_user.c @@ -677,6 +677,7 @@ static void l2fwd(struct xsk_socket_info *xsk, struct pollfd *fds) while (ret != rcvd) { if (ret < 0) exit_with_error(-ret); + complete_tx_l2fwd(xsk, fds); if (xsk_ring_prod__needs_wakeup(&xsk->tx)) kick_tx(xsk); ret = xsk_ring_prod__reserve(&xsk->tx, rcvd, &idx_tx); -- 2.27.0