dtrace discuss - Apr 2008 - Can''t unload module - helper script

Hi,

Lately I was chasing some bug with module unloading, and I forged some
dtrace to give me clues why does not that work. Hope it helps someone.

============================ Sample output ============================Go on

Filename: drv/x25
Modname: x25
Primary module: 0
Reference count: 0 (600024a784c)
Probes enabled: 0
Installed: 1
Loaded: 1
Reqs: 60004ec2d50
Deps: 0

   req: Filename: strmod/x25timer
   req: Modname: x25timer
   req: Primary module: 0
   req: Reference count: 1 (600024a77ac)
   req: Probes enabled: 0
   req: Installed: 1
   req: Loaded: 1
   req: Reqs: 0
   req: Deps: 0

   req: Filename: strmod/s_dlpi
   req: Modname: s_dlpi
   req: Primary module: 0
   req: Reference count: 1 (600024a734c)
   req: Probes enabled: 0
   req: Installed: 1
   req: Loaded: 1
   req: Reqs: 0
   req: Deps: 0

   req: Filename: strmod/x25secu
   req: Modname: x25secu
   req: Primary module: 0
   req: Reference count: 1 (600024a720c)
   req: Probes enabled: 0
   req: Installed: 1
   req: Loaded: 1
   req: Reqs: 0
   req: Deps: 0

detach_driver returns 0
mod_removestrmod returns: 1883769656
mod_name_to_major returns 281
Device reference count 1 (70480aec)
mod_dprintf: Cannot unload device driver <%s>, refcnt %d
mod_removedrv returns: 16
mod_remove returns: 16
moduninstall returns: 16
=======================================================================
-- 
	Vlad
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#!/usr/bin/sh

set -u

PRINT_MODCTL=''
	printf ("%sFilename: %s\n", desc, stringof(mp->mod_filename));
	printf ("%sModname: %s\n", desc, stringof(mp->mod_modname));
	printf ("%sPrimary module: %d\n", desc, mp->mod_prim);
	printf ("%sReference count: %d (%p)\n", desc, mp->mod_ref,
&mp->mod_ref);
	printf ("%sProbes enabled: %d\n", desc, mp->mod_nenabled);
	printf ("%sInstalled: %d\n", desc, mp->mod_installed);
	printf ("%sLoaded: %d\n", desc, mp->mod_loaded);
	printf ("%sReqs: %p\n", desc, mp->mod_requisites);
	printf ("%sDeps: %p\n", desc, mp->mod_dependents);
	printf ("\n");
'';

PRINT_REQ=''
fbt:genunix:moduninstall:entry
/self->reqs/
{
	desc = "   req: ";
	mp =  self->reqs->modl_modp;
	''"$PRINT_MODCTL"''
	self->reqs = self->reqs->modl_next;
}
'';

PRINT_DEP=''
fbt:genunix:moduninstall:entry
/self->deps/
{
	desc = "   dep: ";
	mp =  self->deps->modl_modp;
	''"$PRINT_MODCTL"''
	self->deps = self->deps->modl_next;
}
'';

/usr/sbin/dtrace -n ''

#pragma D option quiet
#pragma D option destructive

BEGIN
{
	printf ("Go on\n\n");
}

fbt:genunix:moduninstall:entry
{
	mp = (struct modctl *)arg0;
	desc = "";
	''"$PRINT_MODCTL"''
	self->reqs = mp->mod_requisites;
	self->deps = mp->mod_dependents;
}

''"$PRINT_REQ"''
''"$PRINT_REQ"''
''"$PRINT_REQ"''

fbt:genunix:moduninstall:entry
/self->reqs/
{
	printf ("   ... and other reqs\n\n");
}

''"$PRINT_DEP"''
''"$PRINT_DEP"''
''"$PRINT_DEP"''

fbt:genunix:moduninstall:entry
/self->deps/
{
	printf ("   ... and other deps\n\n");
}

fbt:genunix:moduninstall:entry
{
	self->reqs = 0;
	self->deps = 0;
	self->go = 1;
}

fbt:genunix:moduninstall:return
{
	self->go = 0; printf ("moduninstall returns: %d\n\n", arg1);
}


fbt:genunix:detach_driver:return
/self->go/
{
	printf ("detach_driver returns %d\n", arg1);
}

mod_remove:entry
/self->go/
{
	self->wild=1;
}

fbt:genunix:mod_remove*:return
/self->go/
{
	printf ("%s returns: %d\n", stringof(probefunc), arg1);
	self->wild=0;
}

fbt:genunix:mod_dprintf:entry
{
	printf ("mod_dprintf: %s", stringof(arg1));
}

fbt:genunix:mod_removedrv:entry
/self->go/
{
	self->mod_removedrv=1;
}

fbt:genunix:mod_name_to_major:return
/self->mod_removedrv/
{
	printf("mod_name_to_major returns %d\n", arg1);
	dp=`devopsp[arg1];
	printf ("Device reference count %d (%p)\n", dp->devo_refcnt,
&(dp->devo_refcnt));
}

fbt:genunix:mod_removedrv:return
/self->go/
{
	self->mod_removedrv=0;
}

''
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