[igt-dev] [PATCH 2/2] i915/perf: Add tests for mapped OA buffer

[Chris Wilson]

Quoting Umesh Nerlige Ramappa (2020-07-30 01:46:03)
> +static void map_oa_buffer_unprivilege_access(void)
> +{
> +       void *vaddr;
> +       uint32_t size;
> +
> +       vaddr = map_oa_buffer(&size);
> +
> +       igt_fork(child, 1) {
> +               igt_drop_root();
> +               try_invalid_access(vaddr);
> +       }
> +       igt_waitchildren();
> +
> +       unmap_oa_buffer(vaddr, size);
> +}

You've also defined the ABI to disallow mmapped access after forking,
even for the privileged user. One more trivial variant to ensure that
holds.
-Chris
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