On Mon, 7 Dec 2020 16:58:01 +0000 (UTC), Christophe Leroy wrote:
> Since commit c33165253492 ("powerpc: use non-set_fs based maccess
> routines"), userspace access is not granted anymore when using
> copy_from_kernel_nofault()
>
> However, kthread_probe_data() uses copy_from_kernel_nofault()
> to check validity of pointers. When the pointer is NULL,
> it points to userspace, leading to a KUAP fault and triggering
> the following big hammer warning many times when you request
> a sysrq "show task":
>
> [...]
Applied to powerpc/fixes.
[1/1] powerpc/mm: Fix KUAP warning by providing copy_from_kernel_nofault_allowed()
https://git.kernel.org/powerpc/c/5eedf9fe8db23313df104576845cec5f481b9b60
cheers
