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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 ACAEAC4338F for ; Wed, 28 Jul 2021 03:07:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D05660F91 for ; Wed, 28 Jul 2021 03:07:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233537AbhG1DHA (ORCPT ); Tue, 27 Jul 2021 23:07:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52182 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233406AbhG1DG6 (ORCPT ); Tue, 27 Jul 2021 23:06:58 -0400 Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8F92EC061757 for ; Tue, 27 Jul 2021 20:06:57 -0700 (PDT) Received: by mail-pl1-x631.google.com with SMTP id f13so1007033plj.2 for ; Tue, 27 Jul 2021 20:06:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=pejIH5+7yKrAyTqV4XSNocnONr/PoCDhuZqzyMXTrGQ=; b=a/FYXZG7THmkwc9n/hIY8ngHLGZJhVNxUCuiqQfnGHxzN/5eTRYfbO5r+uSdsul9oF hxO1f4Lf7+VQvYPDNDYzbe+TvW1GG0Cdq1GUIJRZj5w59LD0Rvv6FVG02qKXp30kwbtp qbGlZ0P0c0FyoQWbAa1y2jHM6aiwez9OcNCBN7UMEDOH7XWSQG4OIPdG5CsaRlPDxzSh FV515tjhu9WCh1+T1Ni0vaQelvUnz/xHClwm9lYclBq9dDEdmiTdDJvOMdRN/XFoMreb eHXGDC38kCfNW+oHftAdjks0DDdzmvGIpOJKNRDUULvKCM9EU05WdEuYhLgAx+GW6XvM 3TvA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=pejIH5+7yKrAyTqV4XSNocnONr/PoCDhuZqzyMXTrGQ=; b=FB9oRFi9bwx+QK9yHq8jLMWaQddWfypP4fUPIpIltH6r4/rTVS3SokiuU+dJwVLONf Y86OI4TM9GFptWFlrGYTkmt4aK36uJ+OpGNT1ENekuZHmTANGkYgxdP7tbpg2wPe8ziR pakpiRLTe0vY9eTCxQ4d9AZ0qO2uh+TkVPRgcpUIABTguwwOS4byaX7teolvjTOkpNMS iVwblxB6DpnDujlMmsHtcof9L19ZK052WPjhByDfr3xirpJPozLIRPq4yTv/IyCV6vVd 316CUlA/xUpIVlQRKTyWVsB4ZfZ5qWHksRaXbP+kJT+tOhskolce++9FgxUDAr78jngR qU6g== X-Gm-Message-State: AOAM530bYITZfFqGLVQOISu1Uu4L6trmilq2D5XluGYJGxOCXqiq2yDI HIGBA2RirB3VjATb2QktqQ0Unnkb84J6nN+7NnE= X-Google-Smtp-Source: ABdhPJzdS7MaWAZCC3ggxLAgis7WQFc+mgr4oBH6vEbdH1n5H3b1pHBBrVipsLDJy7f5aE7YavUE+wdT6TRjFeyzakA= X-Received: by 2002:a17:902:728c:b029:12c:5423:54d8 with SMTP id d12-20020a170902728cb029012c542354d8mr2900564pll.70.1627441616993; Tue, 27 Jul 2021 20:06:56 -0700 (PDT) MIME-Version: 1.0 References: <20210723183630.5088-1-xiyou.wangcong@gmail.com> <610030612aaa3_199a412083d@john-XPS-13-9370.notmuch> In-Reply-To: <610030612aaa3_199a412083d@john-XPS-13-9370.notmuch> From: Cong Wang Date: Tue, 27 Jul 2021 20:06:45 -0700 Message-ID: Subject: Re: [Patch bpf-next] unix_bpf: fix a potential deadlock in unix_dgram_bpf_recvmsg() To: John Fastabend Cc: Linux Kernel Network Developers , Cong Wang , Eric Dumazet , Daniel Borkmann , Jakub Sitnicki , Lorenz Bauer Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Jul 27, 2021 at 9:12 AM John Fastabend wrote: > > Is there a reason to grab the mutex_lock(u->iolock) above the > skb_queue_emptyaand sk_psock_queue_empty checks? > > Could it be move here just above the msg_bytes_ready label? The check of the receive queue is more accurate with lock. Thanks.