Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758711Ab1E0DxK (ORCPT ); Thu, 26 May 2011 23:53:10 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:36765 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753627Ab1E0DxI (ORCPT ); Thu, 26 May 2011 23:53:08 -0400 Subject: Re: [PATCH] SCSI IOCTL: Check for device deletion [was Re: __elv_add_request OOPS] From: James Bottomley To: Parag Warudkar Cc: Linus Torvalds , Jens Axboe , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , Linux SCSI List In-Reply-To: <1306356735.1641.61.camel@mulgrave.site> References: <4DDB8BF6.2000304@fusionio.com> <4DDCB1C8.7040708@fusionio.com> <4DDD5240.2060308@fusionio.com> <4DDD55D6.1080909@fusionio.com> <1306356735.1641.61.camel@mulgrave.site> Content-Type: text/plain; charset="UTF-8" Date: Thu, 26 May 2011 22:53:04 -0500 Message-ID: <1306468385.4048.73.camel@mulgrave.site> Mime-Version: 1.0 X-Mailer: Evolution 2.32.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1466 Lines: 41 On Wed, 2011-05-25 at 15:52 -0500, James Bottomley wrote: > On Wed, 2011-05-25 at 16:42 -0400, Parag Warudkar wrote: > > Yeah - that makes sense. By that logic, looks like we can only disallow > > for SDEV_DEL (if we decide to do that check here). > > I don't think this is the root cause. I think q is non-NULL but has > already been released, so we're just getting a NULL deref on the actual > list head. > > Does this fix it? It adds the refcounting at approximately the correct > places. Of course, we'll now be trying elevator operations on an extant > queue but one whose elevator functions have been destroyed, so there are > probably additional state guards to place. > > James > > --- > > diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c > index 58584dc..44e8ca3 100644 > --- a/drivers/scsi/scsi_scan.c > +++ b/drivers/scsi/scsi_scan.c > @@ -297,7 +297,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget, > kfree(sdev); > goto out; > } > - > + blk_get_queue(sdev->request_queue); Apparently we can't do this because blk_[put|get]_queue aren't exported for use in modules (and SCSI can be modular), so this caused a build failure in linux-next. James -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/