From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932213AbZJAMZc (ORCPT ); Thu, 1 Oct 2009 08:25:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932190AbZJAMZb (ORCPT ); Thu, 1 Oct 2009 08:25:31 -0400 Received: from smtp.ispras.ru ([83.149.198.201]:58964 "EHLO smtp.ispras.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932166AbZJAMZ3 (ORCPT ); Thu, 1 Oct 2009 08:25:29 -0400 Content-Disposition: inline From: iceberg Organization: ISP RAS To: dgilbert@interlog.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [BUG] sg.c: sleeping function called from invalid context Date: Thu, 1 Oct 2009 16:28:05 +0000 User-Agent: KMail/1.10.3 (Linux/2.6.27.29-0.1-default; KDE/4.1.3; x86_64; ; ) MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <200910011628.06870.strakh@ispras.ru> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org KERNEL_VERSION: 2.6.31 DESCRIBE: Driver sg.c might sleep in atomic context, because it calls scsi_device_put under lock_kernel. /drivers/scsi/sg.c:306: static int sg_open(struct inode *inode, struct file *filp) { ... lock_kernel(); ... error_out: if (retval) scsi_device_put(sdp->device); ... Path to might_sleep macro from scsi_device_put: 1. scsi_device_put calls put_device at ./drivers/scsi/scsi.c:1111 2. put_device calls kobject_put at ./drivers/base/core.c:1038 3. kobject_put calls kref_put at ./lib/kobject.c 4. kref_put may call callback function kobject_release at ./lib/kref.c if refcount becomes zero, which might_sleep because it calls user event. Details: 5.1 kobject_cleanup calls kobject_uevent at ./lib/kobject.c:555 5.2 kobject_uevent calls kobject_uevent_env at ./lib/kobject_uevent.c:282 5.3 kobject_uevent_env calls call_usermodehelper_exec at include/linux/kmod.h:83 5.4 call_usermodehelper_exec calls wait_for_completion at ./kernel/kmod.c:481 5.5 wait_for_completion calls wait_for_common at ./kernel/sched.c:5710 5.6 wait_for_common calls might_sleep at ./kernels/sched.c:5692 Found by: Linux Driver Verification