Date: Sun, 3 Mar 96 23:58 WET From: kls@ohare.chicago.com To: FreeBSD-gnats-submit@freebsd.org, kls@chicago.com Subject: kern/1059: null fs panics system Message-ID: <m0ttV9x-0000FbC@ohare.chicago.com> Resent-Message-ID: <199603040800.AAA10354@freefall.freebsd.org>
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>Number: 1059 >Category: kern >Synopsis: null fs panics system >Confidential: no >Severity: critical >Priority: medium >Responsible: freebsd-bugs >State: open >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Mon Mar 4 00:00:00 PST 1996 >Last-Modified: >Originator: Karl Swartz >Organization: Karl Swartz |Home kls@chicago.com |Work kls@slac.stanford.edu |WWW http://www.chicago.com/~kls/ Moderator of sci.aeronautics.airliners -- Unix/network work pays the bills >Release: FreeBSD 2.1-STABLE i386 >Environment: Newly installed FreeBSD 2.1 system (from Walnut Creek CDROM), with selected packages installed (including bash and perl) but no other special software, running the stock kernel on the following hardware: Alaris motherboard with IBM 486SLC2-66 (no 387 installed) 8 MB memory generic IDE controller Maxtor 7420AV disk SMC Ultra Ethernet User home directories in /usr/u/<user>, which preferably would be visible as /u/<user> via a null/lofs mount. Running as nonprivileged user with bash as the default shell. >Description: The system panics as follows when trying to execute a newly created Perl script iff running from a null fs: Fatal trap 12: page fault while in kernel mode fault virtual address = 0x0 fault code = supervisor read, page not present instruction pointer = 0x8:0xf05586fc code segment = base 0x0, limit 0xfffff, type 0x1b = DPL 0, pres 1, def32 1, gran 1 processor eflags = interrupt enabled, resume, IOPL = 0 current process = 1119 (bash) interrupt mask = panic: page fault >How-To-Repeat: (login) $ echo $SHELL /usr/local/bin/bash $ echo $HOME /usr/u/user $ su Password: # mkdir /u # mount -t null /usr/u /u # exit $ cd /u/user $ mkdir panic $ cd panic $ cat >hello <<EOF #!/usr/local/bin/perl print "Hello, world!!!\n"; EOF $ chmod a+x hello $ ./hello Panic occurs at this point immediately and consistently. I'm not sure if the extra directory or creating the script via the null fs matters or not. Running the script again after rebooting will again panic the system. Doing the same with a symlink from /u to /usr/u, or running the script in /usr/u/panic, will not panic the system. I have not tried to see if the problem is specific to bash as the shell and/or perl scripts. >Fix: >Audit-Trail: >Unformatted:
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