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From:   SeongJae Park <sj@kernel.org>
To:     Jianglei Nie <niejianglei2021@163.com>
Cc:     sj@kernel.org, akpm@linux-foundation.org, damon@lists.linux.dev,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org
Subject: Re: [PATCH] mm/damon/reclaim: fix potential memory leak in damon_reclaim_init()
Date:   Thu, 14 Jul 2022 16:44:27 +0000
Message-Id: <20220714164427.157184-1-sj@kernel.org>
In-Reply-To: <20220714063746.2343549-1-niejianglei2021@163.com>
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Hello Jianglei,

On Thu, 14 Jul 2022 14:37:46 +0800 Jianglei Nie <niejianglei2021@163.com> wrote:

> damon_reclaim_init() allocates a memory chunk for ctx with
> damon_new_ctx(). When damon_select_ops() fails, ctx is not released, which
> will lead to a memory leak.
> 
> We should release the ctx with damon_destroy_ctx() when damon_select_ops()
> fails to fix the memory leak.

Thank you for this patch!

I think below tags would be better to be added.

Fixes: 4d69c3457821 ("mm/damon/reclaim: use damon_select_ops() instead of damon_{v,p}a_set_operations()")
Cc: <stable@vger.kernel.org> # 5.18.x

> 
> Signed-off-by: Jianglei Nie <niejianglei2021@163.com>

Reviewed-by: SeongJae Park <sj@kernel.org>


Thanks,
SJ

> ---
>  mm/damon/reclaim.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/damon/reclaim.c b/mm/damon/reclaim.c
> index 4b07c29effe9..0b3c7396cb90 100644
> --- a/mm/damon/reclaim.c
> +++ b/mm/damon/reclaim.c
> @@ -441,8 +441,10 @@ static int __init damon_reclaim_init(void)
>  	if (!ctx)
>  		return -ENOMEM;
>  
> -	if (damon_select_ops(ctx, DAMON_OPS_PADDR))
> +	if (damon_select_ops(ctx, DAMON_OPS_PADDR)) {
> +		damon_destroy_ctx(ctx);
>  		return -EINVAL;
> +	}
>  
>  	ctx->callback.after_wmarks_check = damon_reclaim_after_wmarks_check;
>  	ctx->callback.after_aggregation = damon_reclaim_after_aggregation;
> -- 
> 2.25.1