From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Reed Subject: panic in sg_add when class_device_create() fails Date: Mon, 14 Jan 2008 14:11:36 -0800 Message-ID: <478BDE18.2010600@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from relay2.sgi.com ([192.48.171.30]:37040 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750739AbYANWLj (ORCPT ); Mon, 14 Jan 2008 17:11:39 -0500 Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: linux-scsi , dougg@torque.net Cc: Jeremy Higdon We're seeing an occasional panic in sg_add() when class_device_create() fails. It's obvious in the code that it uses the pointer to sg_class_member even though it's invalid. We do see the "class_device_create failed" message. class_set_devdata(cl_dev, sdp); error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1); if (error) goto cdev_add_err; if (sg_sysfs_valid) { struct class_device * sg_class_member; sg_class_member = class_device_create(sg_sysfs_class, NULL, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), cl_dev->dev, "%s", disk->disk_name); if (IS_ERR(sg_class_member)) printk(KERN_WARNING "sg_add: " "class_device_create failed\n"); class_set_devdata(sg_class_member, sdp); ^^^^^^^^^^^^^^^^ error = sysfs_create_link(&scsidp->sdev_gendev.kobj, &sg_class_member->kobj, "generic"); if (error) printk(KERN_ERR "sg_add: unable to make symlink " "'generic' back to sg%d\n", sdp->index); } else printk(KERN_WARNING "sg_add: sg_sys Invalid\n"); I'm uncertain of the correct fix. Perhaps it involves a call to cdev_unmap()? I don't have a good way to test a fix as this problem is not easily reproduced. Mike