Re: linux-next: manual merge of the uml tree with the mm tree

[Lorenzo Stoakes (ARM)]

On Fri, Sep 25, 2026 at 12:54:35PM +0100, Mark Brown wrote:
> Hi all,
>
> Today's linux-next merge of the uml tree got a conflict in:
>
>   arch/um/Kconfig
>
> between commit:
>
>   f56266a653013 ("mm: make userland page table freeing RCU-safe")
>
> from the mm tree and commit:
>
>   626ff2b34dbb7 ("um: allow deselecting CONFIG_MMU")

Oh nice, nommu UML coming then :)

>
> from the uml tree.
>
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging.  You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
>
> diff --cc arch/um/Kconfig
> index 94b8ff70f578b,59d62c74fc41f..0000000000000
> --- a/arch/um/Kconfig
> +++ b/arch/um/Kconfig
> @@@ -44,10 -45,16 +45,15 @@@ config UM
>   	select HAVE_SYSCALL_TRACEPOINTS
>   	select THREAD_INFO_IN_TASK
>   	select SPARSE_IRQ
>  -	select MMU_GATHER_RCU_TABLE_FREE if MMU
> + 	select UACCESS_MEMCPY if !MMU
> + 	select GENERIC_STRNLEN_USER if !MMU
> + 	select GENERIC_STRNCPY_FROM_USER if !MMU
>
>   config MMU
> - 	bool
> + 	bool "MMU support"
>   	default y
> + 	help
> + 	  Turning this off allows a nommu build, say Y.
>
>   config UML_DMA_EMULATION
>   	bool

LGTM thanks!

--
Cheers, Lorenzo