Date: Wed, 2 Feb 2005 13:02:14 -0500 (EST) From: Mikhail Teterin <mi@aldan.algebra.com> To: FreeBSD-gnats-submit@FreeBSD.org Subject: kern/77026: umount-ing non-existent device panics system Message-ID: <200502021802.j12I2EdM092941@aldan.algebra.com> Resent-Message-ID: <200502021810.j12IAMWj006502@freefall.freebsd.org>
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>Number: 77026 >Category: kern >Synopsis: umount-ing non-existent device panics system >Confidential: no >Severity: serious >Priority: high >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Wed Feb 02 18:10:21 GMT 2005 >Closed-Date: >Last-Modified: >Originator: Mikhail Teterin >Release: FreeBSD 5.3-STABLE i386 >Organization: Virtual Estates, Inc. >Environment: >Description: Every once in a while, a user forgets to umount the file system on a USB "flash-drive" before pulling the device out. The umass-device duly disappears upont the pull-out, but the mount-entry does not. Trying to umount such "fantom" devices results in "device not configured" errors. umount-ing with the `-f' switch crashes the system. I doubt, this is a USB-specific problem -- it is just the easiest way to reproduce the problem. CD-ROMs have hardware protection against this, but disconnecting a hard disk and rescanning the bus will, most probably, lead to the same situation. Note, that this happens even when no writes await and no files are open on the removed devices. `mount -oro -u', for example, succeds. >How-To-Repeat: See description. >Fix: Remember to umount. Still, panic is hardly a reasonable reaction. >Release-Note: >Audit-Trail: >Unformatted:
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