Re: [PATCH] mm/vmalloc: Fix return value check for vb_alloc

[Barry Song <21cnbao@xxxxxxxxx>]

On Wed, Feb 28, 2024 at 9:51 PM 刘海龙(LaoLiu) <liuhailong@xxxxxxxx> wrote:
>
> If vm_map_ram(page, 0, 0) would cause panic by vmap_pages_range_noflush, so
> change IS_ERR to IS_ERR_OR_NULL to fix this.
>
> Signed-off-by: Hailong.Liu <liuhailong@xxxxxxxx>
> ---
>  mm/vmalloc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index d12a17fc0c17..109732006cf7 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2387,7 +2387,7 @@ void *vm_map_ram(struct page **pages, unsigned int
> count, int node)
>
>         if (likely(count <= VMAP_MAX_ALLOC)) {
>                 mem = vb_alloc(size, GFP_KERNEL);
> -               if (IS_ERR(mem))
> +               if (IS_ERR_OR_NULL(mem))

it seems the only case for vb_alloc to return NULL is size = 0, isn't
it a bug of
caller?

>                         return NULL;
>                 addr = (unsigned long)mem;
>         } else {
> --
> 2.34.1

Thanks
Barry