From: Dave Jones <davej@redhat.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Hugh Dickins <hughd@google.com>,
Sasha Levin <sasha.levin@oracle.com>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
Sasha Levin <levinsasha928@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.cz>,
linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org,
florianSchandinat@gmx.de
Subject: Re: tty, vt: lockdep warnings
Date: Tue, 06 Nov 2012 16:42:15 +0000 [thread overview]
Message-ID: <20121106164214.GA18246@redhat.com> (raw)
In-Reply-To: <20121106161100.216c6d79@pyramind.ukuu.org.uk>
On Tue, Nov 06, 2012 at 04:11:00PM +0000, Alan Cox wrote:
> > But a deadlock we have lived with for years. Without reverting,
> > we're prevented from discovering all the new deadlocks we're adding.
>
> We lived with it locking boxes up on users but not knowing why.
Circa 3.5 we got a lot more reports of this happening too for some reason.
Turns out that races are awfully resistant to bisecting too.
> The root
> cause is loading two different framebuffers with one taking over from
> another - that should be an obscure corner case and once the fuzz testing
> can avoid.
>
> I had a semi-informed poke at this and came up with a possible patch (not very tested)
If this fixes the real problems we've been seeing, I'll dance a jig.
Dave
WARNING: multiple messages have this Message-ID (diff)
From: Dave Jones <davej@redhat.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Hugh Dickins <hughd@google.com>,
Sasha Levin <sasha.levin@oracle.com>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
Sasha Levin <levinsasha928@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.cz>,
linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org,
florianSchandinat@gmx.de
Subject: Re: tty, vt: lockdep warnings
Date: Tue, 6 Nov 2012 11:42:15 -0500 [thread overview]
Message-ID: <20121106164214.GA18246@redhat.com> (raw)
In-Reply-To: <20121106161100.216c6d79@pyramind.ukuu.org.uk>
On Tue, Nov 06, 2012 at 04:11:00PM +0000, Alan Cox wrote:
> > But a deadlock we have lived with for years. Without reverting,
> > we're prevented from discovering all the new deadlocks we're adding.
>
> We lived with it locking boxes up on users but not knowing why.
Circa 3.5 we got a lot more reports of this happening too for some reason.
Turns out that races are awfully resistant to bisecting too.
> The root
> cause is loading two different framebuffers with one taking over from
> another - that should be an obscure corner case and once the fuzz testing
> can avoid.
>
> I had a semi-informed poke at this and came up with a possible patch (not very tested)
If this fixes the real problems we've been seeing, I'll dance a jig.
Dave
next prev parent reply other threads:[~2012-11-06 16:42 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-25 19:37 tty, vt: lockdep warnings Sasha Levin
2012-10-26 13:37 ` Alan Cox
2012-10-26 13:37 ` Alan Cox
2012-11-05 17:26 ` Sasha Levin
2012-11-05 17:26 ` Sasha Levin
2012-11-05 17:59 ` Alan Cox
2012-11-05 17:59 ` Alan Cox
2012-11-05 18:00 ` Sasha Levin
2012-11-05 18:00 ` Sasha Levin
2012-11-05 19:17 ` Hugh Dickins
2012-11-05 19:17 ` Hugh Dickins
2012-11-05 20:15 ` Alan Cox
2012-11-05 20:15 ` Alan Cox
2012-11-05 20:34 ` Hugh Dickins
2012-11-05 20:34 ` Hugh Dickins
2012-11-06 16:11 ` Alan Cox
2012-11-06 16:11 ` Alan Cox
2012-11-06 16:42 ` Dave Jones [this message]
2012-11-06 16:42 ` Dave Jones
2012-11-06 17:38 ` Alan Cox
2012-11-06 17:38 ` Alan Cox
2012-11-07 13:47 ` Sasha Levin
2012-11-07 13:47 ` Sasha Levin
2012-11-07 15:57 ` Alan Cox
2012-11-07 16:02 ` Alan Cox
2012-11-07 16:15 ` Bjørn Mork
2012-11-07 16:15 ` Bjørn Mork
2012-11-07 16:56 ` Alan Cox
2012-11-07 17:01 ` Alan Cox
2012-11-08 14:34 ` tty, vt: lockdep warnings (Patch v3) Alan Cox
2012-11-08 14:34 ` Alan Cox
2012-11-09 19:34 ` Hugh Dickins
2012-11-09 19:34 ` Hugh Dickins
2012-11-09 19:42 ` Sasha Levin
2012-11-09 19:42 ` Sasha Levin
2012-11-13 16:24 ` Sasha Levin
2012-11-13 16:24 ` Sasha Levin
2012-11-07 4:29 ` tty, vt: lockdep warnings Hugh Dickins
2012-11-07 4:29 ` Hugh Dickins
2012-11-07 6:26 ` Hugh Dickins
2012-11-07 6:26 ` Hugh Dickins
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