Re: [PATCH] mm/damon/core: initialize damon_target->list in damon_new_target()

[Hyeonggon Yoo]

On Sun, Oct 02, 2022 at 07:31:30PM +0000, SeongJae Park wrote:
> 'struct damon_target' creation function, 'damon_new_target()' is not
> initializing its '->list' field, unlike other DAMON structs creator
> functions such as 'damon_new_region()'.  Normal users of
> 'damon_new_target()' initializes the field by adding the target to DAMON
> context's targets list, but some code could access the uninitialized
> field.
> 
> This commit avoids the case by initializing the field in
> 'damon_new_target()'.
> 
> Reported-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
> Fixes: f23b8eee1871 ("mm/damon/core: implement region-based sampling")
> Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
> ---
> 
>  mm/damon/core.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/mm/damon/core.c b/mm/damon/core.c
> index 1d952fa7ba3e..1e6691771a95 100644
> --- a/mm/damon/core.c
> +++ b/mm/damon/core.c
> @@ -345,6 +345,7 @@ struct damon_target *damon_new_target(void)
>  	t->pid = NULL;
>  	t->nr_regions = 0;
>  	INIT_LIST_HEAD(&t->regions_list);
> +	INIT_LIST_HEAD(&t->list);
>  
>  	return t;
>  }

I tried again with it and this fixes the bug I reported.
Tested-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>

Thank you for such a quick fix!

> -- 
> 2.25.1
> 

-- 
Thanks,
Hyeonggon