From: Fabio Erculiani <lxnay@sabayon.org>
To: "Bruno Prémont" <bonbons@linux-vserver.org>
Cc: linux-fbdev@vger.kernel.org, lethal@linux-sh.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] fbmem: fix race condition between register_framebuffer()
Date: Wed, 25 May 2011 19:16:31 +0000 [thread overview]
Message-ID: <BANLkTikYXtYYV+stQMdgnKhg4MpxZBvgnA@mail.gmail.com> (raw)
In-Reply-To: <20110525211253.4985ee79@neptune.home>
On Wed, May 25, 2011 at 9:12 PM, Bruno Prémont
<bonbons@linux-vserver.org> wrote:
> On Wed, 25 May 2011 Fabio Erculiani <lxnay@sabayon.org> wrote:
>> On Wed, May 25, 2011 at 8:57 PM, Bruno Prémont wrote:
>> > On Wed, 25 May 2011 Fabio Erculiani <lxnay@sabayon.org> wrote:
>> >> On Wed, May 25, 2011 at 8:46 PM, Bruno Prémont wrote:
>> >> > On Wed, 25 May 2011 Fabio Erculiani <lxnay@sabayon.org> wrote:
>> >> >> I'm not a fbdev expert. So I leave the real fix to real men ( ;-) ).
>> >> >> It is causing deadlock during boot, so I would consider it quite critical.
>> >> >> Users using any fb driver will get into troubles.
>> >> >> The workaround is to boot with vga=normal.
>> >> >
>> >> > What is your system doing during boot? I've never seen it here but maybe
>> >> > my boot sequence is too simple.
>> >>
>> >> I'm using vesafb and vgay1. It is quite simple to reproduce.
>> >> Also see: http://bugs.gentoo.org/show_bug.cgi?id68109
>> >
>> > Looks like gentoo kernel, might be splash is related to the hang
>>
>> Then, if you say so, it must be the fbsplash patch for sure, I keep
>> forgetting of that :-/
>
> I've had a look at the bug report which points at fbcon_decore
> patch.
>
> Looking into that patch confirms my impression:
> fbcon_decor calls a userspace helper at the time fbcon takes over
> console and that userspace helper then tries to open fb device
> with the aim of calling some IOCTLs.
>
> Probably changing fbcon_decor to just call the userspace helper in
> non-blocking mode (or having userspace helper "fork and detach") would
> avoid the deadlock as well.
> Though fbcon_decor seems to rely on helper's return code...
>
> What is the matching piece on userspace side so I can look at it as well?
I guess you're talking about this:
http://fbsplash.berlios.de/wiki/doku.php
the package is named splashutils, and contains userspace helpers.
>
> Bruno
>
--
Fabio Erculiani
prev parent reply other threads:[~2011-05-25 19:16 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-24 19:54 [PATCH] fbmem: fix race condition between register_framebuffer() and fb_open() Fabio Erculiani
2011-05-24 20:45 ` [PATCH] fbmem: fix race condition between Bruno Prémont
2011-05-25 16:19 ` Bruno Prémont
2011-05-25 18:17 ` [PATCH] fbmem: fix race condition between register_framebuffer() Fabio Erculiani
2011-05-25 18:41 ` Anca Emanuel
2011-05-25 18:48 ` Fabio Erculiani
2011-05-25 18:51 ` [PATCH] fbmem: fix race condition between Bruno Prémont
2011-05-25 18:53 ` [PATCH] fbmem: fix race condition between register_framebuffer() Fabio Erculiani
2011-05-25 18:46 ` [PATCH] fbmem: fix race condition between Bruno Prémont
2011-05-25 18:52 ` [PATCH] fbmem: fix race condition between register_framebuffer() Fabio Erculiani
2011-05-25 18:57 ` [PATCH] fbmem: fix race condition between Bruno Prémont
2011-05-25 19:04 ` [PATCH] fbmem: fix race condition between register_framebuffer() Fabio Erculiani
2011-05-25 19:12 ` [PATCH] fbmem: fix race condition between Bruno Prémont
2011-05-25 19:16 ` Fabio Erculiani [this message]
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