[BUG] completely bonkers use of set_need_resched + VM_FAULT_NOPAGE

Daniel Vetter daniel.vetter at ffwll.ch
Thu Sep 12 13:23:02 PDT 2013

On Thu, Sep 12, 2013 at 10:20 PM, Thomas Gleixner <tglx at linutronix.de> 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.
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

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