Date: Wed, 13 Sep 2006 23:02:36 GMT From: Martin <nakal@web.de> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/103245: mount -o rw, umount may panic system Message-ID: <200609132302.k8DN2aWC044529@www.freebsd.org> Resent-Message-ID: <200609132310.k8DNAIHb043622@freefall.freebsd.org>
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>Number: 103245 >Category: kern >Synopsis: mount -o rw, umount may panic system >Confidential: no >Severity: non-critical >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Wed Sep 13 23:10:17 GMT 2006 >Closed-Date: >Last-Modified: >Originator: Martin >Release: FreeBSD 6.1R >Organization: >Environment: FreeBSD 6.1-RELEASE FreeBSD 6.1-RELEASE #0: Sat May 13 00:26:37 CEST 2006 >Description: Under certain circumstances, it is possible to cause a panic while remounting and unmounting an originally read-only mounted UFS file system. >How-To-Repeat: fstab which I'm using contains entries to my old FreeBSD installation: [...] /dev/ad0s3a /freebsd-old ufs ro 0 0 /dev/ad0s3f /freebsd-old/var ufs ro 0 0 /dev/ad0s3d /freebsd-old/usr ufs ro 0 0 /dev/ad0s3e /freebsd-old/usr/home ufs ro 0 0 Everything is read-only and mounted after boot. Now, try to remount: # mount -o rw /freebsd-old/usr/home # mount [...] /dev/ad0s3a on /freebsd-old (ufs, local, read-only) /dev/ad0s3f on /freebsd-old/var (ufs, local, read-only) /dev/ad0s3d on /freebsd-old/usr (ufs, local, read-only) /dev/ad0s3e on /freebsd-old/usr/home (ufs, local, read-only) /dev/ad0s3e on /freebsd-old/usr/home (ufs, local, read-only) You see two entries of /dev/ad0s3e, both of them read-only. From here on, try a few more "mount -o rw /freebsd-old/usr/home" and "umount /freebsd-old/usr/home". This will result in a panic. (Note: # mount -o rw /dev/ad0s3e /freebsd-old/usr/home mount: /dev/ad0s3e: Operation not permitted Please reproduce it, exactly with the steps above. ) >Fix: >Release-Note: >Audit-Trail: >Unformatted:
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