From owner-freebsd-bugs  Thu Mar 21 05:44:34 1996
Return-Path: owner-bugs
Received: (from root@localhost)
          by freefall.freebsd.org (8.7.3/8.7.3) id FAA26881
          for bugs-outgoing; Thu, 21 Mar 1996 05:44:34 -0800 (PST)
Received: from frig.mt.cs.keio.ac.jp (frig.mt.cs.keio.ac.jp [131.113.32.7])
          by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id FAA26860
          Thu, 21 Mar 1996 05:44:29 -0800 (PST)
Received: (from hosokawa@localhost) by frig.mt.cs.keio.ac.jp (8.6.12+2.4W/3.4Wbeta3) id WAA08147; Thu, 21 Mar 1996 22:44:16 +0900
Date: Thu, 21 Mar 1996 22:44:16 +0900
Message-Id: <199603211344.WAA08147@frig.mt.cs.keio.ac.jp>
To: pst@shockwave.com
Cc: bde@freebsd.org, hackers@freebsd.org, bugs@freebsd.org, jmz@freebsd.org,
        hosokawa@mt.cs.keio.ac.jp
Subject: dev_attach after boot (Re: modloaded block/char device drivers)
In-Reply-To: Your message of Thu, 21 Mar 1996 00:37:51 -0800.
	<199603210837.AAA00354@precipice.shockwave.com>
From: hosokawa@mt.cs.keio.ac.jp (HOSOKAWA Tatsumi)
X-Mailer: mnews [version 1.18PL3] 1994-08/01(Mon)
Sender: owner-bugs@freebsd.org
X-Loop: FreeBSD.org
Precedence: bulk

Hi.

I'm working on PC-card driver package of FreeBSD.

In article <199603210837.AAA00354@precipice.shockwave.com>
pst@shockwave.com writes:

>> (a) calling dev_attach() from a modloaded device panics the system.
>>     I have not even attempted to mess with this yet,  but it can be
>>     trivially reproduced by removing the #ifndef ACTUALL_LKM_NOT_KERNEL
>>     wrappers around the call in qcam.c.  It panics with a kernel page
>>     fault, but the current calling chain did /not/ include any of the
>>     qcam routines in the stack frame.  I just found this by scratching
>>     my head and looking to see what I did that the joystick routine
>>     didn't do.

I'm facing the same problem with pccard drivers on 2.2.

When I try to enable (hotplug) Flash ATA (wdc and wd) driver or SCSI
devices (cd, sd, etc.), the kernel panic()'s by kernel page fault.

I found it never panics when I commented out the calls of dev_attach()
in those drivers.

I think that dev_attach() of 2.2 has serious bug in dynamic
reconfiguration of devices (dev_attach() of 2.1 has no problem in
these operations).

--
	HOSOKAWA, Tatsumi              E-mail: hosokawa@mt.cs.keio.ac.jp
	  WWW homepage: http://www.mt.cs.keio.ac.jp/person/hosokawa.html
	Department of Computer Science, Keio University, Yokohama, Japan