Bug 19572

Summary:	executing command cd ../cdrom after mount-unmount-mount causes trap 12 and kernel panic.
Product:	Base System	Reporter:	ahampi <ahampi>
Component:	kern	Assignee:	Alfred Perlstein <alfred>
Status:	Closed FIXED
Severity:	Affects Only Me
Priority:	Normal
Version:	Unspecified
Hardware:	Any
OS:	Any

Description ahampi 2000-06-29 06:00:00 UTC

Executing cd ../cdrom from /cdrom directory after cycle of mount-umount-
mount cycle causes trap 12 (page fault while in kernel mode) and hence
causes kernel panic.

Fix: 

No idea.
How-To-Repeat: chdir to /cdrom (which) is default mount point for cdrom as per fstab.
mount /cdrom and do ls
now umount -f /cdrom (force as we will be /cdrom)
doing ls will give error( . not a directory)
do mount /cdrom to mount the cdrom once again (we are still in /cdrom dir)
now do ls will give error once again
now do cd ../ (tab in case of bash or esc in case of csh) to do file
completion.
This will result in trap 12 (page fault in kernel mode) and thus
results in kernel panic.

Comment 1 Joseph Koshy freebsd_committer

2000-11-02 09:27:37 UTC

I have been able to reproduce this panic on a 4.1.1-STABLE system and a
5-CURRENT system of Sep 5 2000 vintage.

Regards,
Koshy
<jkoshy@freebsd.org>

Comment 2 Alfred Perlstein freebsd_committer

2000-11-30 20:43:26 UTC

Responsible Changed
From-To: freebsd-bugs->alfred

Applied patch in PR/23191 will close if the patch resolves the issue.

Comment 3 iedowse freebsd_committer

2001-05-20 13:12:21 UTC

State Changed
From-To: open->closed


Fixed in -current and -stable (vfs_lookup.c rev 1.41 and 1.38.2.2 
respectively). Thanks for the bug report!