Re: tty, vt: lockdep warnings

From: Dave Jones
Date: Tue Nov 06 2012 - 11:42:37 EST


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

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