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SubjectRe: fix a hyperv W^X violation and remove vmalloc_exec
On Thu, Jun 18, 2020 at 08:43:04AM +0200, Christoph Hellwig wrote:
> Hi all,
>
> Dexuan reported a W^X violation due to the fact that the hyper hypercall
> page due switching it to be allocated using vmalloc_exec. The problem
> is that PAGE_KERNEL_EXEC as used by vmalloc_exec actually sets writable
> permissions in the pte. This series fixes the issue by switching to the
> low-level __vmalloc_node_range interface that allows specifing more
> detailed permissions instead. It then also open codes the other two
> callers and removes the somewhat confusing vmalloc_exec interface.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

> Peter noted that the hyper hypercall page allocation also has another
> long standing issue in that it shouldn't use the full vmalloc but just
> the module space. This issue is so far theoretical as the allocation is
> done early in the boot process. I plan to fix it with another bigger
> series for 5.9.

Thanks!

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