Re: [PATCH] mm: correct type for vmalloc vm_flags fields

[Vlastimil Babka <vbabka@suse.cz>]

On 7/29/25 13:49, Lorenzo Stoakes wrote:
> Several functions refer to the unfortunately named 'vm_flags' field when
> referencing vmalloc flags, which happens to be the precise same name used
> for VMA flags.
> 
> As a result these were erroneously changed to use the vm_flags_t type
> (which currently is a typedef equivalent to unsigned long).
> 
> Currently this has no impact, but in future when vm_flags_t changes this
> will result in issues, so change the type to unsigned long to account for
> this.
> 
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Reported-by: Harry Yoo <harry.yoo@oracle.com>
> Closes: https://lore.kernel.org/all/aIgSpAnU8EaIcqd9@hyeyoo/

Acked-by: Vlastimil Babka <vbabka@suse.cz>

also for "mm: fixup very disguised vmalloc flags parameter" later in this thread

> ---
>  mm/execmem.c  | 8 ++++----
>  mm/internal.h | 2 +-
>  mm/nommu.c    | 2 +-
>  3 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/mm/execmem.c b/mm/execmem.c
> index 627e6cf64f4f..2b683e7d864d 100644
> --- a/mm/execmem.c
> +++ b/mm/execmem.c
> @@ -26,7 +26,7 @@ static struct execmem_info default_execmem_info __ro_after_init;
> 
>  #ifdef CONFIG_MMU
>  static void *execmem_vmalloc(struct execmem_range *range, size_t size,
> -			     pgprot_t pgprot, vm_flags_t vm_flags)
> +			     pgprot_t pgprot, unsigned long vm_flags)
>  {
>  	bool kasan = range->flags & EXECMEM_KASAN_SHADOW;
>  	gfp_t gfp_flags = GFP_KERNEL | __GFP_NOWARN;
> @@ -82,7 +82,7 @@ struct vm_struct *execmem_vmap(size_t size)
>  }
>  #else
>  static void *execmem_vmalloc(struct execmem_range *range, size_t size,
> -			     pgprot_t pgprot, vm_flags_t vm_flags)
> +			     pgprot_t pgprot, unsigned long vm_flags)
>  {
>  	return vmalloc(size);
>  }
> @@ -256,7 +256,7 @@ static void *__execmem_cache_alloc(struct execmem_range *range, size_t size)
> 
>  static int execmem_cache_populate(struct execmem_range *range, size_t size)
>  {
> -	vm_flags_t vm_flags = VM_ALLOW_HUGE_VMAP;
> +	unsigned long vm_flags = VM_ALLOW_HUGE_VMAP;
>  	struct vm_struct *vm;
>  	size_t alloc_size;
>  	int err = -ENOMEM;
> @@ -373,7 +373,7 @@ void *execmem_alloc(enum execmem_type type, size_t size)
>  {
>  	struct execmem_range *range = &execmem_info->ranges[type];
>  	bool use_cache = range->flags & EXECMEM_ROX_CACHE;
> -	vm_flags_t vm_flags = VM_FLUSH_RESET_PERMS;
> +	unsigned long vm_flags = VM_FLUSH_RESET_PERMS;
>  	pgprot_t pgprot = range->pgprot;
>  	void *p;
> 
> diff --git a/mm/internal.h b/mm/internal.h
> index 28d2d5b051df..142d9302c2ae 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -1391,7 +1391,7 @@ int migrate_device_coherent_folio(struct folio *folio);
> 
>  struct vm_struct *__get_vm_area_node(unsigned long size,
>  				     unsigned long align, unsigned long shift,
> -				     vm_flags_t vm_flags, unsigned long start,
> +				     unsigned long vm_flags, unsigned long start,
>  				     unsigned long end, int node, gfp_t gfp_mask,
>  				     const void *caller);
> 
> diff --git a/mm/nommu.c b/mm/nommu.c
> index 87e1acab0d64..07504d666d6a 100644
> --- a/mm/nommu.c
> +++ b/mm/nommu.c
> @@ -126,7 +126,7 @@ void *vrealloc_noprof(const void *p, size_t size, gfp_t flags)
> 
>  void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
>  		unsigned long start, unsigned long end, gfp_t gfp_mask,
> -		pgprot_t prot, vm_flags_t vm_flags, int node,
> +		pgprot_t prot, unsigned long vm_flags, int node,
>  		const void *caller)
>  {
>  	return __vmalloc_noprof(size, gfp_mask);
> --
> 2.50.1