Re: [PATCH 2/3] drm/scheduler: Fix UAF in drm_sched_fence_get_timeline_name

From: Lucas Stach
Date: Thu Nov 02 2023 - 07:20:03 EST


Am Donnerstag, dem 02.11.2023 um 11:48 +0100 schrieb Christian König:
[...]
> I was considering to change the dma_fence semantics so that
> dma_fence_signal() could only be called from the interrupt contexts of
> devices and then put a big fat WARN_ON(!in_interrupt()) in there.
>
> It's a sledgehammer, but as far as I can see the only thing which might
> help. Opinions?

That's not going to fly. As soon as you are dealing with device drivers
that use IRQ threads, either voluntarily or even involuntarily on RT
kernels, the dma_fence_signal will be from process context.

Regards,
Lucas