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 <guro@xxxxxx>
> Signed-off-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
Acked-by: Roman Gushchin <guro@xxxxxx>
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
>
>
>
