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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 A7B63C43603 for ; Tue, 17 Dec 2019 13:24:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 76B0120717 for ; Tue, 17 Dec 2019 13:24:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="XxoE+Uh0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728261AbfLQNYY (ORCPT ); Tue, 17 Dec 2019 08:24:24 -0500 Received: from mail-pf1-f170.google.com ([209.85.210.170]:43037 "EHLO mail-pf1-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726191AbfLQNYY (ORCPT ); Tue, 17 Dec 2019 08:24:24 -0500 Received: by mail-pf1-f170.google.com with SMTP id h14so5650947pfe.10 for ; Tue, 17 Dec 2019 05:24:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=to:cc:from:subject:message-id:date:user-agent:mime-version :content-transfer-encoding:content-language; bh=HBXv6Gs3P+0i/KNOn2YdFsnpMYPur7Aw9mvLprhquV8=; b=XxoE+Uh0AjAd3pbtS2StGPWsJjFRNkJyeJ3RKselW4QJcaMXb+ZnEX5PgtPp9XiHh9 V+W6jo5aG4hM83VlY3jF53/wNvthAaWgazKeh0W/kZEH8IdsyFiRL67Sol9tLYoZ51un sPeAYJL132w/FndU1jZGuzHIBtuNDPwM96HLW8qBmTUf15/PUW5H1iRoEebB2e40scgz hqIFRk+QygJkgiFxitLuPEE6WG6j/ZN7LM5L8/tdusjglE0nBNt16Spzqx3JQWJf/X8s k0g4geysjOFlV7jre0UG3wPgtK/Fcr+aUh89B/CFU/krk+5JGLlbP4up0zgNDWJUYRtA VBcg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:cc:from:subject:message-id:date:user-agent :mime-version:content-transfer-encoding:content-language; bh=HBXv6Gs3P+0i/KNOn2YdFsnpMYPur7Aw9mvLprhquV8=; b=Lz2Uz71CmE8GDD5jR/RyZtVvZSUmi9GtBXt1VlWvyXlzTneO03pte8DqoEKIQ0Qrhm IgC/T36mWQoTuD0Bgt4EkqTjiQXA6vR8s2eVUZv9wR4KDClcFT58UPiRzrqw/qZyAfee u61I/dRfpH5RQqzaRF72U3EZjFyUR8h7/F86q6KtHEDL7iVfFpYmPvpyhj3dkOvoxCCU evZxm0osTdTMVytu+l3bmJdzcJU6AoqQErWDVUz3BfpOnCZukfBxihXho0NIuK6YcGBV ByZ4G3oUrtqyRn7GTu/3nin5KS8zo5jvTCiGo9rRK+71aZrQAEBzQZpY/DwZ0u0pWw6/ 35vg== X-Gm-Message-State: APjAAAXF2nLIK2DlLuq2yqBKWkXLkbG3w+Xbt5aZ/D5dmcFK7ALCExgM kzo0QgBo/rnvFsUpAvGHaFcxDlDpP2o= X-Google-Smtp-Source: APXvYqxi95Sr2LOuuq1q/0lIrPuElPZFBUt8fhDipjA17PKllLPGZZ+tq45wt9LtNo65tcEYS2NbYg== X-Received: by 2002:a63:4f5c:: with SMTP id p28mr24594475pgl.409.1576589063189; Tue, 17 Dec 2019 05:24:23 -0800 (PST) Received: from ?IPv6:2402:f000:1:1501:200:5efe:166.111.139.134? ([2402:f000:1:1501:200:5efe:a66f:8b86]) by smtp.gmail.com with ESMTPSA id p4sm27783708pfb.157.2019.12.17.05.24.20 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 17 Dec 2019 05:24:22 -0800 (PST) To: perex@perex.cz, tiwai@suse.com, rfontana@redhat.com, gregkh@linuxfoundation.org, allison@lohutok.net, tglx@linutronix.de Cc: alsa-devel@alsa-project.org, LKML From: Jia-Ju Bai Subject: [BUG] ALSA: seq: a possible sleep-in-atomic-context bug in snd_virmidi_dev_receive_event() Message-ID: Date: Tue, 17 Dec 2019 21:24:21 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The driver may sleep while holding a read lock. The function call path (from bottom to top) in Linux 4.19 is: sound/core/seq/seq_memory.c, 96:     copy_from_user in snd_seq_dump_var_event sound/core/seq/seq_virmidi.c, 97:     snd_seq_dump_var_event in snd_virmidi_dev_receive_event sound/core/seq/seq_virmidi.c, 88:     _raw_read_lock in snd_virmidi_dev_receive_event copy_from_user() can sleep at runtime. I am not sure how to properly fix this possible bug, so I only report it. This bug is found by a static analysis tool STCheck written by myself. Best wishes, Jia-Ju Bai