Date: Tue, 7 Mar 2006 17:27:44 -0800
From: Greg KH <greg@kroah.com>
To: Dmitry Torokhov <dtor_core@ameritech.net>
Cc: Linus Torvalds <torvalds@osdl.org>,
       Chuck Ebbert <76306.1226@compuserve.com>, Andrew Morton <akpm@osdl.org>,
       Ingo Molnar <mingo@elte.hu>,
       linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Fw: Re: oops in choose_configuration()
Message-ID: <20060308012744.GA24739@kroah.com>
References: <200603071657_MC3-1-BA0F-6372@compuserve.com> <Pine.LNX.4.64.0603071648430.32577@g5.osdl.org> <200603072013.29227.dtor_core@ameritech.net>
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On Tue, Mar 07, 2006 at 08:13:28PM -0500, Dmitry Torokhov wrote:
> On Tuesday 07 March 2006 19:57, Linus Torvalds wrote:
> > 
> > On Tue, 7 Mar 2006, Chuck Ebbert wrote:
> > > 
> > > At least one susbsystem rolls its own method of adding env vars to the
> > > uevent buffer, and it's so broken it triggers the WARN_ON() in
> > > lib/vsprintf.c::vsnprintf() by passing a negative length to that function.
> > 
> > Well, snprintf() should be safe, though. It will warn if the caller is 
> > lazy, but these days, the thing does
> > 
> > 	max(buf_size - len, 0)
> > 
> > which should mean that the input layer passes in 0 instead of a negative 
> > number. And snprintf() will then _not_ print anything. 
> > 
> > So I think input_add_uevent_bm_var() is safe, even if it's not pretty.
> > 
> > However, input_devices_read() doesn't do any sanity checking at all, and 
> > if that ever ends up printing more than a page, that would be bad. I 
> > didn't look very closely, but it looks worrisome.
> > 
> > Dmitry?
> 
> I had all this code converted to seq_file, but it depends on converting
> input handlers to class interfaces and it is not possible nowadays
> because with latest Greg's changes to class code we would try to
> register class devices while registering class devices/interfaces
> (psmouse creates input_dev which binds to mousedev interface which in
> turn tries to create mouseX which is also belongs to input class) and
> deadlocking. Greg promised current implementation is only a temporary
> solution.
> 
> I suppose I could separate those changes...

That would probably be a good idea :)

Oh, and I have been working on makeing the correct fix, you can see the
initial try of it at:
	http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/device-class.patch
if you are really brave :)

thanks,

greg k-h
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