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Date: Sun, 25 Feb 1996 01:46:47 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199602241446.BAA07462@godzilla.zeta.org.au>
To: freebsd-hackers@FreeBSD.ORG, j@uriah.heep.sax.de
Subject: Re: Whither ddb
Sender: owner-hackers@FreeBSD.ORG
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>Debugger("serial console break")
>Stopped at      _Debugger+0x2b: movb    $0,_in_Debugger.110
>db> x curproc
>_curproc:               f0434200
>db> c
>clearing /tmp
>recording kernel -c changes
>starting system daemons: syslogd.
>starting network daemons: named portmap inetd.
>load: 0.76  cmd: dev_mkdb 76 [biowait] 0.16u 0.16s 0% 420k
>standard daemons: cron printer sendmail.
>setting ldconfig path: /usr/lib /usr/X11R6/lib /usr/local/lib
>Debugger("

>Fatal trap 9: general protection fault while in kernel mode
>instruction pointer     = 0x8:0xf0102ce5
>code segment            = base 0x0, limit 0xfffff, type 0x1b
>                        = DPL 0, pres 1, def32 1, gran 1
>processor eflags        = resume, IOPL = 0
>current process         = 93 (ldconfig)
>interrupt mask          = 
>kernel: type 9 trap, code=0
>Stopped at      _db_printf_guts+0x335:  repne scasb     (%esi)

>*** arrgh.  what you see here looks like a kernel bug :-(( ***

>Does anybody know offhand why dp_printf_guts() might cause a general
>protection fault?  (#GP -- sounds like winglows, eh! :)

Probably a bad pointer.  Entering ddb with the serial console break
is apparently unsafe.  ddb needs to run with interrupts disabled since
its caller needs them disabled , but this isn't guaranteed.

Bruce