Re: [PATCH] mm/vmalloc: Fix incorrect size reporting on allocation failure

[Mikulas Patocka <mpatocka@redhat.com>]

On Mon, 2 Mar 2026, Uladzislau Rezki (Sony) wrote:

> When __vmalloc_area_node() fails to allocate pages, the failure
> message may report an incorrect allocation size, for example:
> 
>   vmalloc error: size 0, failed to allocate pages, ...
> 
> This happens because the warning prints area->nr_pages * PAGE_SIZE.
> At this point, area->nr_pages may be zero or partly populated thus
> it is not valid.
> 
> Report the originally requested allocation size instead by using
> nr_small_pages * PAGE_SIZE, which reflects the actual number of
> pages being requested by user.
> 
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> ---
>  mm/vmalloc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 61caa55a4402..a06f4b3ea367 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -3901,7 +3901,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
>  		if (!fatal_signal_pending(current) && page_order == 0)
>  			warn_alloc(gfp_mask, NULL,
>  				"vmalloc error: size %lu, failed to allocate pages",
> -				area->nr_pages * PAGE_SIZE);
> +				nr_small_pages * PAGE_SIZE);
>  		goto fail;
>  	}
>  
> -- 
> 2.47.3

Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>

Mikulas