Am 30.11.21 um 13:31 schrieb Thomas Hellström:

[SNIP]

...

Other than that, I didn't investigate the nesting fails enough to say I can accurately review this. :)

Basically the problem is that within enable_signaling() which is called with the dma_fence lock held, we take the dma_fence lock of another fence. If that other fence is a dma_fence_array, or a dma_fence_chain which in turn tries to lock a dma_fence_array we hit a splat.

Yeah, I already thought that you constructed something like that.

You get the splat because what you do here is illegal, you can't mix dma_fence_array and dma_fence_chain like this or you can end up in a stack corruption.

Regards, Christian.

But I'll update the commit message with a typical splat.

/Thomas