From owner-freebsd-current Mon Feb 11 19:46: 8 2002 Delivered-To: freebsd-current@freebsd.org Received: from newman2.bestweb.net (newman2.bestweb.net [209.94.102.67]) by hub.freebsd.org (Postfix) with ESMTP id 9657737B62E; Mon, 11 Feb 2002 18:18:53 -0800 (PST) Received: from okeeffe.bestweb.net (okeefe.bestweb.net [209.94.100.110]) by newman2.bestweb.net (Postfix) with ESMTP id 305602322E; Mon, 11 Feb 2002 21:17:53 -0500 (EST) Received: by okeeffe.bestweb.net (Postfix, from userid 0) id C21C89F394; Mon, 11 Feb 2002 21:12:36 -0500 (EST) Date: Sun, 10 Feb 2002 05:08:37 -0500 (EST) From: Mikhail Teterin Subject: Re: panic: bdwrite: buffer is not busy To: bde@zeta.org.au Cc: jhb@FreeBSD.ORG, current@FreeBSD.ORG Message-Id: <20020212021236.C21C89F394@okeeffe.bestweb.net> Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On 10 Feb, Bruce Evans wrote: > On Sat, 9 Feb 2002, John Baldwin wrote: > >> On 09-Feb-02 Mikhail Teterin wrote: >> > While attempting to ``fdisk fd0.1440''. Or ``fdisk fd0''. Or >> > ``newfs_msdos fd0.1440'' with or without the floppy inside :-\ With >> > todays or Jan 3rd kernel (my previous upgrade). >> >> Only use fdisk on hard disks. Still it shouldn't panic. The bdwrite >> is just extra garbage, the real panic is due to a NULL pointer >> dereference: > > This is a well known bug in the device layer. I reported it on > 2001/12/26 and fixed it locally a little later. See the thread in > -current about "panic during fdisk'ing a md(4) device" for patches. Fdisk I don't really need, but attempting to newfs the floppy caused the same panic :-\ And mounting the already formatted floppy leads to "invalid argument". Could we have this fixed soon, please? The inability to access a floppy is a great setback for my local FreeBSD advocacy efforts :-) -mi >> I'm guessing that devsw() is returning NULL here. You could add a >> KASSERT() to this macro just before the call to d_strategy() along >> the lines of >> >> KASSERT(devsw((bp)->bio_dev) != NULL, ("no devsw for bio")); \ > > Right. From my original bug report: > > ! "fdisk /dev/fd0" now causes a null pointer panic in readdisklabel(). > ! This is because fdioctl() attempts to construct a (slightly > ! wrong) device using dkmodpart(), but dkmodpart() only constructs a > ! half-baked device since it only calls makedev(). The device is > ! missing a devsw so DEV_STRATEGY() in readdisklabel() panics on it. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message