Re: kextunload problem
Re: kextunload problem
- Subject: Re: kextunload problem
- From: "Mark Stow" <email@hidden>
- Date: Tue, 27 Jun 2006 15:24:44 +0000
thanks again - sorry - I've not posted anything before!
my free() calls super::free(). In an effort to find out why it's not
unloading, all the life cycle functions just call super (and IOLog for some
diags).
any ideas why logging out and back in again would cure this kextunload fail
issue?
From: "Herb Petschauer" <email@hidden>
To: "Mark Stow" <email@hidden>
CC: email@hidden
Subject: Re: kextunload problem
Date: Tue, 27 Jun 2006 07:37:40 -0700
Ok, top posting it is... :-)
Look at the OSObject.cpp code, I think the retain count is set to "1" in
the
constructor, so I would expect the release() calls to go one beyond the
retain() calls.
A simple solution, does your free() method call super::free()? That's my
mistake 9 times of out 10.
See also this thread: <
http://lists.apple.com/archives/darwin-drivers/2006/May/msg00091.html>
hth,
-H.
On 27/06/06, Mark Stow <email@hidden> wrote:
Herb, thanks. I have some more info -
The system log tells me there is one instance of my class which is why it
can't unload. It doesn't make any difference if the firewire device is
plugged in or not.
I tried overriding retain() and release(), and in both cases when
kextunload
fails or succeeds, release() seems to be called once more than retain().
I also noticed that if I delete the driver from system/library/extensions
and reboot, so it's not loaded on boot, and then copy it back and kextload
it, kextunload will succeed.
If someone is over-retaining (and it seems to need to happen on bootup)
wouldn't I see a difference in the retain() release() counts when unload
fails?
>From: "Herb Petschauer" < email@hidden>
>To: "Mark Stow" <email@hidden>
>CC: email@hidden
>Subject: Re: kextunload problem
>Date: Mon, 26 Jun 2006 09:18:45 -0700
>
>On 26/06/06, Mark Stow <email@hidden > wrote:
>>
>>Hi - I'm having some difficulties with kextunload.
>>I am working on a firewire device driver which derives from IOService.
>>The
>>problem seems to be that free() never gets called. However, if I log
out,
>>then log back in again, everything works fine - ie free() is called,
and
>>the
>>driver unloads correctly.
>>I have stripped the code down to a bare minimum of just the life cycle
>>functions, which in turn just call into IOService. I see init(),
attach()
>>and start() being called, and then on unload stop() detach() but not
>>free().
>> Any help/ideas would be appreciated!
>>
>>
>>
>
>Check your system.log, there's probably a message telling you why your
kext
>won't unload (e.g. Couldn't unload kext (name) because there are x
>instances
>of <some class>). free() doesn't get called until the last release()
>(retain/release must balance) so I suspect someone is
over-retaining(). Is
>your Firewire drive unplugged when you try and unload the kext? The
>/dev/disk nodes are usually left created until you unplug the
device. Just
>a thought...
>
>-H.
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