linux-kernel - Re: [PATCH] [v2] alloc_tag: hide execmem

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Message-ID: <CAJuCfpFqTBnY10HUzBf3Xbqg0iAe2-=GegU4RSpysBgXX9+H9w@mail.gmail.com>
Date: Mon, 28 Oct 2024 11:53:38 -0700
From: Suren Baghdasaryan <surenb@...gle.com>
To: Arnd Bergmann <arnd@...nel.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>, Pasha Tatashin <pasha.tatashin@...een.com>, 
	Arnd Bergmann <arnd@...db.de>, Mike Rapoport <rppt@...nel.org>, Luis Chamberlain <mcgrof@...nel.org>, 
	Song Liu <song@...nel.org>, "Masami Hiramatsu (Google)" <mhiramat@...nel.org>, linux-mm@...ck.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [v2] alloc_tag: hide execmem_vmap() on !MMU

On Mon, Oct 28, 2024 at 8:04 AM Arnd Bergmann <arnd@...nel.org> wrote:
>
> From: Arnd Bergmann <arnd@...db.de>
>
> The newly added function fails to link on nommu kernels, but is also
> not needed there:
>
> ld.lld-20: error: undefined symbol: __get_vm_area_node
> >>> referenced by execmem.c
> >>>               mm/execmem.o:(execmem_vmap) in archive vmlinux.a
> >>> referenced by execmem.c
> >>>               mm/execmem.o:(execmem_vmap) in archive vmlinux.a
>
> Move it into the #ifdef block along with execmem_vmalloc().
>
> Fixes: 57bc3834fb6f ("alloc_tag: populate memory for module tags as needed")
> Acked-by: Mike Rapoport (Microsoft) <rppt@...nel.org>
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

Sorry, replied to your older version. Copying here:

Thanks for the fix but execmem_vmap() is used if
CONFIG_MEM_ALLOC_PROFILING=y. Please give me an hour to post a fix
dealing with that.

> ---
>  mm/execmem.c | 32 ++++++++++++++++----------------
>  1 file changed, 16 insertions(+), 16 deletions(-)
>
> diff --git a/mm/execmem.c b/mm/execmem.c
> index 5c0f9f2d6f83..317b6a8d35be 100644
> --- a/mm/execmem.c
> +++ b/mm/execmem.c
> @@ -64,6 +64,22 @@ static void *execmem_vmalloc(struct execmem_range *range, size_t size,
>
>         return p;
>  }
> +
> +struct vm_struct *execmem_vmap(size_t size)
> +{
> +       struct execmem_range *range = &execmem_info->ranges[EXECMEM_MODULE_DATA];
> +       struct vm_struct *area;
> +
> +       area = __get_vm_area_node(size, range->alignment, PAGE_SHIFT, VM_ALLOC,
> +                                 range->start, range->end, NUMA_NO_NODE,
> +                                 GFP_KERNEL, __builtin_return_address(0));
> +       if (!area && range->fallback_start)
> +               area = __get_vm_area_node(size, range->alignment, PAGE_SHIFT, VM_ALLOC,
> +                                         range->fallback_start, range->fallback_end,
> +                                         NUMA_NO_NODE, GFP_KERNEL, __builtin_return_address(0));
> +
> +       return area;
> +}
>  #else
>  static void *execmem_vmalloc(struct execmem_range *range, size_t size,
>                              pgprot_t pgprot, unsigned long vm_flags)
> @@ -368,22 +384,6 @@ void execmem_free(void *ptr)
>                 vfree(ptr);
>  }
>
> -struct vm_struct *execmem_vmap(size_t size)
> -{
> -       struct execmem_range *range = &execmem_info->ranges[EXECMEM_MODULE_DATA];
> -       struct vm_struct *area;
> -
> -       area = __get_vm_area_node(size, range->alignment, PAGE_SHIFT, VM_ALLOC,
> -                                 range->start, range->end, NUMA_NO_NODE,
> -                                 GFP_KERNEL, __builtin_return_address(0));
> -       if (!area && range->fallback_start)
> -               area = __get_vm_area_node(size, range->alignment, PAGE_SHIFT, VM_ALLOC,
> -                                         range->fallback_start, range->fallback_end,
> -                                         NUMA_NO_NODE, GFP_KERNEL, __builtin_return_address(0));
> -
> -       return area;
> -}
> -
>  void *execmem_update_copy(void *dst, const void *src, size_t size)
>  {
>         return text_poke_copy(dst, src, size);
> --
> 2.39.5
>