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=-3.6 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 C422DC433E1 for ; Sun, 23 Aug 2020 15:30:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9BB9220724 for ; Sun, 23 Aug 2020 15:30:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="LjjwogIY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727124AbgHWP2y (ORCPT ); Sun, 23 Aug 2020 11:28:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45702 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726632AbgHWP2t (ORCPT ); Sun, 23 Aug 2020 11:28:49 -0400 Received: from mail-lj1-x234.google.com (mail-lj1-x234.google.com [IPv6:2a00:1450:4864:20::234]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E976C061573 for ; Sun, 23 Aug 2020 08:28:48 -0700 (PDT) Received: by mail-lj1-x234.google.com with SMTP id v9so6878483ljk.6 for ; Sun, 23 Aug 2020 08:28:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to:cc; bh=0i/vx9dNh0duIZo+YYHyl28QUKMLxr//hpEhD6kAgqs=; b=LjjwogIYDeFUTHNbp4QMu4XgZ3F4VsaZ7Vn3iUVW0uslddwXpg5K3ze0E6oe4ojuqQ 1bdXLBBI224W2qFCm/ojTpiEoyZoKGnkbrc2FmerfxRcZ6BVkm2hxrOgc6fXDDgZpLR8 EaBDN4gZwCBDltGjAVNSk9alMpNx6ASRoQeM9TsyYAlvMLuoUnX865BcbPggHVKYxvN/ jWtPAc24w5IRliyFQ9kDu8B/w4B0dAoU7LHvQc/ZWHTXPLdTFnagTcmZNaOspM3RyIlo RQKEOitqiFJRPOPKICrrPsTLpaRTnLaLQy9bzKP9cMPgGz8wSm4VDoY1UmXD7bDFFwDa vtCw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to:cc; bh=0i/vx9dNh0duIZo+YYHyl28QUKMLxr//hpEhD6kAgqs=; b=KrSFaBvVbzMVcQJs5sQlq5JX+AcDNtR1oEG0tgaOsJAmOP+COxJZFLTIsMas7hfpGX ffplfAKRPSd8RJuYtEr/K83ldmsJz3S3JebjMkOWSd3Bfk5oowQMC0geUgCTmdOXB8sB 64qn9H8lhUnVAU/m8fm+4zzrLxcaZtde073qxp0vJLDbemuSuhWOFPy1wQUuyVvMaTMB zgRPhCBB3mDlk4vpUciEglQZscupIsv7ZPyV3AHBDed6uClZMFB67ZD8T6UuO4OMzGZY psf6Ju6BK+MCv8CRCy46NDyJ5mptv7sDzhMxPb2kHm214lWO6QTzqPk9Lk3ilsclKzli eReg== X-Gm-Message-State: AOAM5308MuXC53HjqR0CrTN8fh+LEiI85vDkm7V+Wy/9BYDOopxxG6fj +bbEFzMWWw/2zP/HJqLY1x9Z/Pwe3tIbq+Vjj2vPxnoftg== X-Google-Smtp-Source: ABdhPJwUwLbit0CVmGr4/iOy4oMlhcSATLyCptnRsZP5QAAiBxld5gaWNEqf474rK4p5WQqa6FkvjYILwIe/SXUGkVY= X-Received: by 2002:a2e:983:: with SMTP id 125mr858881ljj.32.1598196524777; Sun, 23 Aug 2020 08:28:44 -0700 (PDT) MIME-Version: 1.0 From: Madhuparna Bhowmik Date: Sun, 23 Aug 2020 20:58:33 +0530 Message-ID: Subject: Regarding possible bug in net/wan/x25_asy.c To: David Miller , Jakub Kicinski , xie.he.0141@gmail.com Cc: andrianov , netdev Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hello, I have the following doubt: sl->xhead is modified in both x25_asy_change_mtu() and x25_asy_write_wakeup(). However, sl->lock is not held in x25_asy_write_wakeup(). So, I am not sure if it is indeed possible to have a race between these two functions. If it is possible that these two functions can execute in parallel then the lock should be held in x25_asy_write_wakeup() as well. Please let me know if this race is possible. Thanks and regards, Madhuparna