linux-kernel - Re: kobject ->k

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Message-ID: <20071203204716.GA9734@suse.de>
Date:	Mon, 3 Dec 2007 12:47:16 -0800
From:	Greg KH <gregkh@...e.de>
To:	Alexey Dobriyan <adobriyan@...ru>
Cc:	akpm@...l.org, linux-kernel@...r.kernel.org, kay.sievers@...y.org
Subject: Re: kobject ->k_name memory leak

On Mon, Dec 03, 2007 at 12:26:07PM +0300, Alexey Dobriyan wrote:
> Hi, Greg!
> 
> Commit ce2c9cb0259acd2aed184499ebe41ab00da13b25 aka
> "kobject: remove the static array for the name" introduced memory leak
> of a module name after modprobe/rmmod. Apparently for modules ->release
> callback is NULL.
> 
> kobject_cleanup: ->release = 00000000, name = 'foo_sysctl'
> Pid: 1927, comm: rmmod Not tainted 2.6.24-rc3-e1cca7e8d484390169777b423a7fe46c7021fec1 #5
>  [<c10d4a58>] kobject_cleanup+0xb8/0xc0
>  [<c10d4a60>] kobject_release+0x0/0x10
>  [<c10d587b>] kref_put+0x2b/0xa0
>  [<c11dbe85>] _spin_unlock+0x25/0x40
>  [<c1045b78>] free_module+0x78/0xd0
>  [<c104773f>] sys_delete_module+0x12f/0x1a0

Hm, _which_ kobject associated with a module, there are 3 of them I
think :)

They should all have a release function, and if they do not, we think
it's a "static" kobject and it is not safe to free that name.

I've been working on cleaning this up a lot in the -mm tree with over 80
patches for the kset/kobject apis and interfaces.

But if we have a dynamic kobject, and we aren't freeing it properly,
please let me know which one it is and I'll work to fix it for 2.6.24.

thanks,

greg k-h
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