On Thu, Oct 23 2014, Laurent Pinchart wrote:
> If activation of the CMA area fails its mutex won't be initialized,
> leading to an oops at allocation time when trying to lock the mutex. Fix
> this by failing allocation if the area hasn't been successfully actived,
> and detect that condition by moving the CMA bitmap allocation after page
> block reservation completion.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v3.17
Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
As a matter of fact, this is present in kernels earlier than 3.17 but in
the 3.17 the code has been moved from drivers/base/dma-contiguous.c to
mm/cma.c so this might require separate stable patch. I can track this
and prepare a patch if you want.
> ---
> mm/cma.c | 17 ++++++-----------
> 1 file changed, 6 insertions(+), 11 deletions(-)
>
> diff --git a/mm/cma.c b/mm/cma.c
> index 963bc4a..16c6650 100644
> --- a/mm/cma.c
> +++ b/mm/cma.c
> @@ -93,11 +93,6 @@ static int __init cma_activate_area(struct cma *cma)
> unsigned i = cma->count >> pageblock_order;
> struct zone *zone;
>
> - cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> -
> - if (!cma->bitmap)
> - return -ENOMEM;
> -
> WARN_ON_ONCE(!pfn_valid(pfn));
> zone = page_zone(pfn_to_page(pfn));
>
> @@ -114,17 +109,17 @@ static int __init cma_activate_area(struct cma *cma)
> * to be in the same zone.
> */
> if (page_zone(pfn_to_page(pfn)) != zone)
> - goto err;
> + return -EINVAL;
> }
> init_cma_reserved_pageblock(pfn_to_page(base_pfn));
> } while (--i);
>
> + cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> + if (!cma->bitmap)
> + return -ENOMEM;
> +
> mutex_init(&cma->lock);
> return 0;
> -
> -err:
> - kfree(cma->bitmap);
> - return -EINVAL;
> }
>
> static int __init cma_init_reserved_areas(void)
> @@ -313,7 +308,7 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
> struct page *page = NULL;
> int ret;
>
> - if (!cma || !cma->count)
> + if (!cma || !cma->count || !cma->bitmap)
> return NULL;
>
> pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
> --
> 2.0.4
>
--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michał “mina86” Nazarewicz (o o)
ooo +--<mpn@xxxxxxxxxx>--<xmpp:mina86@xxxxxxxxxx>--ooO--(_)--Ooo--
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