Re: [PATCH] Revert "MIPS: make userspace mapping young by default"

[Andrew Morton]

On Wed, 26 May 2021 11:43:35 +0200 Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> wrote:

> This reverts commit f685a533a7fab35c5d069dcd663f59c8e4171a75.
> 
> MIPS cache flush logic needs to know whether the mapping was already
> established to decide how to flush caches. This is done by checking the
> valid bit in the PTE. The commit above breaks this logic by setting
> the valid in the PTE in new mappings, which causes kernel crashes.

Thanks.  I added

Fixes: f685a533a7f ("MIPS: make userspace mapping young by default")
Cc: <stable@xxxxxxxxxxxxxxx>