Re: [tip: x86/urgent] x86/mm/pat: Fix effective RW computation in lookup_address_in_pgd_attr()

[Dave Hansen]

On 9/4/26 21:42, Nathan Chancellor wrote:
> I just bisected the following warning on a couple of my test machines to
> commit 453e78594434 ("x86/mm/pat: Fix effective RW computation in
> lookup_address_in_pgd_attr()") in next-20260904.
...
> If there is any information I can provide to help debug this, I am happy
> to provide it.

Well, the thing you bisected to is the patch that fixes the warning. The
actual issue comes from:

        if (pages == &its_pages)
                set_memory_x((unsigned long)page, 1);

which its_alloc() does on an execmem allocation. Any chance you could
get the output of:

	/sys/kernel/debug/page_tables/current_kernel

for the page that page that it's complaining about? I'm curious if this
is temporary or permanent. its_pages_protect() should be fixing this up
at the end of things, so there would be no permanent harm just a
temporary violation of CONFIG_STRICT_MODULE_RWX.

Peter, shouldn't we be using the text poking mm for things like this?