On Wed, Jun 03, 2020 at 08:40:24PM +1200, Barry Song wrote:
> if users give a name saved in stack, the current code will generate magic
> pointer.
> if users don't give a name(NULL), kasprintf() will always return NULL as
> we are at the early stage. that means cma_init_reserved_mem() will return
> -ENOMEM if users set name parameter as NULL.
> 
> Cc: Roman Gushchin <[email protected]>
> Signed-off-by: Barry Song <[email protected]>

Acked-by: Roman Gushchin <[email protected]>

Thanks!

> ---
>  mm/cma.c | 13 ++++++-------
>  mm/cma.h |  4 +++-
>  2 files changed, 9 insertions(+), 8 deletions(-)
> 
> diff --git a/mm/cma.c b/mm/cma.c
> index 0463ad2ce06b..b24151fa2101 100644
> --- a/mm/cma.c
> +++ b/mm/cma.c
> @@ -202,13 +202,12 @@ int __init cma_init_reserved_mem(phys_addr_t base, 
> phys_addr_t size,
>        * subsystems (like slab allocator) are available.
>        */
>       cma = &cma_areas[cma_area_count];
> -     if (name) {
> -             cma->name = name;
> -     } else {
> -             cma->name = kasprintf(GFP_KERNEL, "cma%d\n", cma_area_count);
> -             if (!cma->name)
> -                     return -ENOMEM;
> -     }
> +
> +     if (name)
> +             snprintf(cma->name, CMA_MAX_NAME, name);
> +     else
> +             snprintf(cma->name, CMA_MAX_NAME,  "cma%d\n", cma_area_count);
> +
>       cma->base_pfn = PFN_DOWN(base);
>       cma->count = size >> PAGE_SHIFT;
>       cma->order_per_bit = order_per_bit;
> diff --git a/mm/cma.h b/mm/cma.h
> index 33c0b517733c..27d3f0e9f68f 100644
> --- a/mm/cma.h
> +++ b/mm/cma.h
> @@ -2,6 +2,8 @@
>  #ifndef __MM_CMA_H__
>  #define __MM_CMA_H__
>  
> +#define CMA_MAX_NAME 64
> +
>  struct cma {
>       unsigned long   base_pfn;
>       unsigned long   count;
> @@ -12,7 +14,7 @@ struct cma {
>       struct hlist_head mem_head;
>       spinlock_t mem_head_lock;
>  #endif
> -     const char *name;
> +     char name[CMA_MAX_NAME];
>  };
>  
>  extern struct cma cma_areas[MAX_CMA_AREAS];
> -- 
> 2.23.0
> 
> 
> 

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