Re: [PATCH v2] fs/proc/task_mmu: add VM_SHADOW_STACK for arm64 when support GCS

[David Hildenbrand <david@redhat.com>]

On 07.06.25 15:15, wangfushuai wrote:
> The recent commit adding VM_SHADOW_STACK for arm64 GCS did not update
> the /proc/[pid]/smaps display logic to show the "ss" flag for GCS pages.
> This patch adds the necessary condition to display "ss" flag.
> 
> Fixes: ae80e1629aea ("mm: Define VM_SHADOW_STACK for arm64 when we support GCS")
> Signed-off-by: wangfushuai <wangfushuai@baidu.com>
> ---
>   fs/proc/task_mmu.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> index 27972c0749e7..2c2ee893a797 100644
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -994,6 +994,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
>   #ifdef CONFIG_ARCH_HAS_USER_SHADOW_STACK
>   		[ilog2(VM_SHADOW_STACK)] = "ss",
>   #endif
> +#if defined(CONFIG_ARM64_GCS)
> +		[ilog2(VM_SHADOW_STACK)] = "ss",
> +#endif

Which makes me wonder why we don't select 
CONFIG_ARCH_HAS_USER_SHADOW_STACK for CONFIG_ARM64_GCS?

>   #if defined(CONFIG_64BIT) || defined(CONFIG_PPC32)
>   		[ilog2(VM_DROPPABLE)] = "dp",
>   #endif


-- 
Cheers,

David / dhildenb