Re: [BUG] completely bonkers use of set_need_resched +VM_FAULT_NOPAGE

From: Thomas Gleixner
Date: Thu Sep 12 2013 - 16:39:41 EST


On Thu, 12 Sep 2013, Daniel Vetter wrote:

> On Thu, Sep 12, 2013 at 10:20 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> >> I think for ttm drivers it's just execbuf being exploitable. But on
> >> drm/i915 we've
> >> had the same issue with the pwrite/pread ioctls, so a simple
> >> glBufferData(glMap) kind of recursion from gl clients blew the kernel
> >> to pieces ...
> >
> > And the only answer you folks came up with is set_need_resched() and
> > yield()? Oh well....
>
> The yield was for a different lifelock, and that one is also fixed by
> now. The fault handler deadlock was fixed in the usual "drop locks and
> jump into slowpath" fasion, at least in drm/i915.

So we can remove that whole yield/set_need_resched() mess completely ?

Thanks,

tglx
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