From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 17 Sep 2001 00:58:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 17 Sep 2001 00:57:57 -0400 Received: from gear.torque.net ([204.138.244.1]:40463 "EHLO gear.torque.net") by vger.kernel.org with ESMTP id ; Mon, 17 Sep 2001 00:57:44 -0400 Message-ID: <3BA5759B.B5743C6D@torque.net> Date: Mon, 17 Sep 2001 00:01:31 -0400 From: Douglas Gilbert X-Mailer: Mozilla 4.77 [en] (X11; U; Linux 2.4.10-pre9 i586) X-Accept-Language: en MIME-Version: 1.0 To: Jens Axboe CC: lkml@krimedawg.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org Subject: Re: OOPS in scsi generic stuff 2.4.10-pre6 In-Reply-To: <3BA4CB70.50B4A3AB@torque.net> <20010916182208.B9006@suse.de> <20010916185522.D9006@suse.de> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jens Axboe wrote: > > On Sun, Sep 16 2001, Jens Axboe wrote: > > It looks like a race in that sg_cmd_done_bh can be completed before > > generic_unplug_device is called (and thus on a free'd scsi request). We > > then pass an invalid queue to generic_unplug_device. > > (corrected version, scsi_allocate_request can of course fail) Jens, Prior to this patch (actually the first one you posted today) sg_dd would frequently crash in generic_unplug_device when tested against the scsi_debug adapter driver. [I have hacked up that driver to simulate a large number of (ram) disks to test Richard Gooch's 2000+ scsi disk patch.] The way scsi_debug handles all its commands, the bottom half handler in sg will be called before scsi_do_req() completes. With this patch the problem goes away. Doug Gilbert