Re: [PATCH v2] mm/gup: Fix memory leak in __gup_benchmark_ioctl

David Hildenbrand
2019-12-16T12:18:55Z

On 13.12.19 23:37, Navid Emamdoost wrote:
> In the implementation of __gup_benchmark_ioctl() the allocated pages
> should be released before returning in case of an invalid cmd. Release
> pages via kvfree() by goto done.
>
> Fixes: 714a3a1ebafe ("mm/gup_benchmark.c: add additional pinning methods")
> Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
> ---
> Changes in v2:
> -- added goto and ret value instead of return -1.
> ---
> mm/gup_benchmark.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c
> index b160638f647e..b773b2568544 100644
> --- a/mm/gup_benchmark.c
> +++ b/mm/gup_benchmark.c
> @@ -24,7 +24,7 @@ static int __gup_benchmark_ioctl(unsigned int cmd,
> {
> ktime_t start_time, end_time;
> unsigned long i, nr_pages, addr, next;
> - int nr;
> + int nr, ret = 0;
> struct page **pages;
>
> if (gup->size > ULONG_MAX)
> @@ -63,8 +63,8 @@ static int __gup_benchmark_ioctl(unsigned int cmd,
> NULL);
> break;
> default:
> - kvfree(pages);
> - return -1;
> + ret = -EINVAL;
> + goto done;
> }
>
> if (nr <= 0)
> @@ -85,8 +85,9 @@ static int __gup_benchmark_ioctl(unsigned int cmd,
> end_time = ktime_get();
> gup->put_delta_usec = ktime_us_delta(end_time, start_time);
>
> +done:
> kvfree(pages);
> - return 0;
> + return ret;
> }
>
> static long gup_benchmark_ioctl(struct file *filep, unsigned int cmd,
>

You should really CC people that give review feedback in previous
iterations (IOW me :) ) and properly tag versions/mention code change
since the last version.

(v1 was already <20191122224117.2372-1-navid.emamdoost@gmail.com>, this
here would be v3)

Also, this patch here is not a standalone patch, it is an addon on top
of <20191211174653.4102-1-navid.emamdoost@gmail.com>

Enough rambling :) This squashed into
<20191211174653.4102-1-navid.emamdoost@gmail.com>:

Reviewed-by: David Hildenbrand <david@redhat.com>

I agree that the label could have a better name (e.g., out_free)

--
Thanks,

David / dhildenb