2022-07-24 07:00:12

by Jianglei Nie

Subject: [PATCH] mm/damon/reclaim: fix potential memory leak in damon_reclaim_init()

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.

Fixes: 4d69c3457821 ("mm/damon/reclaim: use damon_select_ops() instead of damon_{v,p}a_set_operations()")
Signed-off-by: Jianglei Nie <[email protected]>
---
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

2022-07-24 07:23:15

by Greg Kroah-Hartman

Subject: Re: [PATCH] mm/damon/reclaim: fix potential memory leak in damon_reclaim_init()

On Sun, Jul 24, 2022 at 02:52:24PM +0800, Jianglei Nie 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.
>
> Fixes: 4d69c3457821 ("mm/damon/reclaim: use damon_select_ops() instead of damon_{v,p}a_set_operations()")
> Signed-off-by: Jianglei Nie <[email protected]>
> ---
> 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
>

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree. Please read:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>

2022-07-24 10:17:03

by SeongJae Park

Subject: Re: [PATCH] mm/damon/reclaim: fix potential memory leak in damon_reclaim_init()

Hi Jianglei and Greg,

On Sun, 24 Jul 2022 09:18:52 +0200 Greg KH <[email protected]> wrote:

> On Sun, Jul 24, 2022 at 02:52:24PM +0800, Jianglei Nie 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.
> >
> > Fixes: 4d69c3457821 ("mm/damon/reclaim: use damon_select_ops() instead of damon_{v,p}a_set_operations()")
> > Signed-off-by: Jianglei Nie <[email protected]>
> > ---
> > 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
> >
>
> <formletter>
>
> This is not the correct way to submit patches for inclusion in the
> stable kernel tree. Please read:
> https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> for how to do this properly.
>
> </formletter>

Thank you for the notice, Greg. Jianglei, please read that great document.

And Andrew already added the 'Fixes:' and 'Cc: stable@' tags in the patch when
he added[1] it in the mm tree. Hence I think this would be merged in the
appropriate stable series once it gets merged in the mainline.

[1] https://lore.kernel.org/mm-commits/[email protected]/


Thanks,
SJ