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To: Bruce Evans <bde@zeta.org.au>
cc: freebsd-bugs@freebsd.org, Shimon@i-Connect.Net
Subject: Re: Mystery of the X11 Panic... 
In-reply-to: Your message of "Mon, 21 Apr 1997 18:52:09 +1000."
             <199704210852.SAA27852@godzilla.zeta.org.au> 
From: David Greenman <dg@root.com>
Reply-To: dg@root.com
Date: Mon, 21 Apr 1997 03:31:50 -0700
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>[cc list trimmed to remove -hackers]
>
>>Fatal trap 12 - Page fault while in kernel mode. in virtual address
>>0xf71e0014.  Tracing back shows that bash (?!) was the culprit, causing it
>>after calling _Xsyscall -> _syscall -> _vm_open -> _spec_open.
>>
>>Things go south at _spec_open + 0x6e, complaining about cmpl $0,0(%eax).
>
>This means that cdevsw[maj]->d_open is bad (probably null) although
>cdevsw[maj] != NULL.  This might be caused by a buggy or stale LKM.
>Driver LKM's tend to cause this problem if they are unloaded.  Bash
>may trigger the problem because it does an opendir() on device files
>(but I thought I fixed this by not opening device files in opendir()).
>I wouldn't use LKMs for anything important.

   ...or it could be caused by the bug in kern_exec.c, which could have
mangled adjacent buffers or possibly random kernel memory. It seems
to involve bash and the kern_exec.c bug was triggered when running small
shell scripts.

-DG

David Greenman
Core-team/Principal Architect, The FreeBSD Project