arm32 insecure W+X mapping

[Russell King (Oracle)]

On Thu, Aug 19, 2021 at 10:19:46AM -0700, Tim Harvey wrote:
> Greetings,
> 
> Since commit a8e53c151fe7 "(ARM: 8737/1: mm: dump: add checking for
> writable and executable)" I've been seeing the following appear on my
> arm32 kernel:
> 
> arm/mm: Found insecure W+X mapping at address 0xf087d000
> ...
> Checked W+X mappings: FAILED, 1 W+X pages found
> 
> As I haven't seen others report this I assume it's something unique to
> my kernel configuration. How do I debug what is causing the insecure
> page?

If you check /proc/vmallocinfo, it should tell you the physical
address that was mapped there, and the function that created the
mapping. That should give enough clues to track it down.

Thanks.

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