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=-13.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 CEF7EC49361 for ; Mon, 28 Jun 2021 16:24:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B67F861455 for ; Mon, 28 Jun 2021 16:24:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233693AbhF1Q1I (ORCPT ); Mon, 28 Jun 2021 12:27:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33708 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233588AbhF1Q1I (ORCPT ); Mon, 28 Jun 2021 12:27:08 -0400 Received: from mail-vk1-xa2f.google.com (mail-vk1-xa2f.google.com [IPv6:2607:f8b0:4864:20::a2f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9FFE2C061766 for ; Mon, 28 Jun 2021 09:24:41 -0700 (PDT) Received: by mail-vk1-xa2f.google.com with SMTP id ay19so4056627vkb.9 for ; Mon, 28 Jun 2021 09:24:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RpJ7w32iGqwOk/oM/d0ecaefQixseDwgEeakcU32Bpk=; b=J5VVzZnCPxO4E4iVGvXs0S0FNIqPMIYqCPljwFsfMFBLSG5Xf/XsoDBBgz7XgOAHmm vj7AoYTLWtcJtxnNJHMOS4ONGe4/xLbiLzUhOqtIS+2VZ8TjR/p4Jp/sjGyshvcYALQV jiVsg2puI6vff5H82ZCHshluIz/QfrLLq8Q1ODcK2NxRkPvQDq4NlK8sQLRWj/URdKEZ ZLO4SE0JpCoP3lPkkachFV5wjB0I/V2WtBgJTHN8spUvLb5bKq89e41L9bsmNvmMK9vp dTyECvKDxu/nb0CWQCyyvTe4MPcCoERzBGkhHsCI7FYD+dGi9i2beYvViJ6+e6YeCT47 NvBw== 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=RpJ7w32iGqwOk/oM/d0ecaefQixseDwgEeakcU32Bpk=; b=EIBTRMrjT3myyLsiLPNND0rywIwtyRzhd0VXP0KIBB4d8JtH8BoKrgm15G2T+xwa4h xo7eZZrbrPePWt37gQk4yBeX0lUbAtyFEPuHWraisUwyIa/oidOsctusKSP2xcxrmSK7 YpFR5/6o2jare+C/j9h24xr5hILRXWyc7lQV1f0OoFSwkW9DsAcWXCWzCpql/KurWrgx K/fz3wDXSWCQQCEbaWf7Zr3uyrqPgJGWHDZlB2AeHQU0msPhSvIh3Q6ncXpvXLZQP5VP tu9HuTkbK/XmuczrwHEamRg7vY50chFFJ7/hklZ8WBtzJb3ocRlUF/Ubn7ZCuTZNHme9 +SDQ== X-Gm-Message-State: AOAM530UP+3zs6ao9I7K4gNPtrrW3V/09/6khDTYYhPC4bTU9Z/AyzUk rCI0LPf3h4+tJL779kGNQ7HVESNXhS2eSx9HWcJqFw== X-Google-Smtp-Source: ABdhPJw91nOsdpuFZV/dLpAyCemkIwoeS+zWUP869PzyBrf5GyGV7tXMqGOVFz318/U7RCY6IgxhF5tRCxgIjbMCSos= X-Received: by 2002:a1f:280e:: with SMTP id o14mr17539002vko.19.1624897480401; Mon, 28 Jun 2021 09:24:40 -0700 (PDT) MIME-Version: 1.0 References: <20210628144908.881499-1-phind.uet@gmail.com> <79490158-e6d1-aabf-64aa-154b71205c74@gmail.com> In-Reply-To: <79490158-e6d1-aabf-64aa-154b71205c74@gmail.com> From: Neal Cardwell Date: Mon, 28 Jun 2021 12:24:19 -0400 Message-ID: Subject: Re: [PATCH] tcp: Do not reset the icsk_ca_initialized in tcp_init_transfer. To: Phi Nguyen Cc: Eric Dumazet , David Miller , Hideaki YOSHIFUJI , David Ahern , Jakub Kicinski , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , John Fastabend , kpsingh@kernel.org, netdev , LKML , bpf , linux-kernel-mentees@lists.linuxfoundation.org, syzbot+f1e24a0594d4e3a895d3@syzkaller.appspotmail.com, Yuchung Cheng Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Mon, Jun 28, 2021 at 12:18 PM Phi Nguyen wrote: > > On 6/28/2021 10:52 PM, Eric Dumazet wrote: > > > Unfortunately this patch might break things. > > > > We keep changing this CC switching, with eBPF being mixed in the equation. > > > > I would suggest you find a Fixes: tag first, so that we can continue > > the discussion. > > > > Thank you. > > Thank for your feedback. I will resubmit it with a Fixes tag. > > Regard. Thanks. Can you also please provide a summary of the event sequence that triggers the bug? Based on your Reported-by tag, I guess this is based on the syzbot reproducer: https://groups.google.com/g/syzkaller-bugs/c/VbHoSsBz0hk/m/cOxOoTgPCAAJ but perhaps you can give a summary of the event sequence that causes the bug? Is it that the call: setsockopt$inet_tcp_TCP_CONGESTION(r0, 0x6, 0xd, &(0x7f0000000000)='cdg\x00', 0x4) initializes the CC and happens before the connection is established, and then when the connection is established, the line that sets: icsk->icsk_ca_initialized = 0; is incorrect, causing the CC to be initialized again without first calling the cleanup code that deallocates the CDG-allocated memory? thanks, neal