From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Anderson Subject: Re: Linux-2.6.0-test4: Kernel Panic in scsi_host_dev_release Date: Mon, 25 Aug 2003 16:42:32 -0700 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20030825234232.GA2470@beaverton.ibm.com> References: <1061844849.486.12.camel@felicia> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from e31.co.us.ibm.com ([32.97.110.129]:53997 "EHLO e31.co.us.ibm.com") by vger.kernel.org with ESMTP id S261705AbTHYXig (ORCPT ); Mon, 25 Aug 2003 19:38:36 -0400 Content-Disposition: inline In-Reply-To: <1061844849.486.12.camel@felicia> List-Id: linux-scsi@vger.kernel.org To: "Dr. Ernst Molitor" Cc: James.Bottomley@SteelEye.com, linux-scsi@vger.kernel.org Dr. Ernst Molitor [molitor@uni-bonn.de] wrote: > Dear James E.J. Bottomley, > > while Linux-2.6.0-test3 runs like a charm on my (testbed) box, I ran > into a kernel panic with Linux-2.6.0-test4 (and 2.6.0-test4-bk4). > > The call trace is: > > scsi_host_dev_release > device_releases > kobject_cleanup > aha1542_detect > init_this_scsi_driver > do_initcalls > init_workqueues > init > init > kernel_thread_helper I believe the problem you are hitting is a bug in the code I added for a doing a put on the parent in the release function. If a driver calls scsi_register, but then has a problem in there detect where they need to call scsi_unregister the parent pointer of the struct device may never be set. I you have time could you please try the patch below. I have compiled it only. I will try to run it with a modified driver that will fail in detect shortly. > The last line of both functions is identical: kfree is called with the > pointer shost. From a very superficial analysis, I would feel that > freeing *dev rather than *shost would be logical, but I might very well > be way off the real source of the panic I have seen. > We need to kfree the shost as the struct device is contained inside the scsi_host structure. -andmike -- Michael Anderson andmike@us.ibm.com drivers/scsi/hosts.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletion(-) diff -puN drivers/scsi/hosts.c~scsi_host_dev_release-parent-fix drivers/scsi/hosts.c --- qla-bleed-2.5/drivers/scsi/hosts.c~scsi_host_dev_release-parent-fix Mon Aug 25 15:42:53 2003 +++ qla-bleed-2.5-andmike/drivers/scsi/hosts.c Mon Aug 25 15:43:19 2003 @@ -158,7 +158,8 @@ static void scsi_host_dev_release(struct scsi_proc_hostdir_rm(shost->hostt); scsi_destroy_command_freelist(shost); - put_device(parent); + if (parent) + put_device(parent); kfree(shost); } _