linux-kernel - Re: [PATCH v1 1/2] mm/ksm: support fork/exec for prctl

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Message-ID: <a86b8604-befe-23d9-3f7b-34dbaf399adf@redhat.com>
Date:   Wed, 20 Sep 2023 15:11:21 +0200
From:   David Hildenbrand <david@...hat.com>
To:     Stefan Roesch <shr@...kernel.io>, kernel-team@...com
Cc:     akpm@...ux-foundation.org, hannes@...xchg.org, riel@...riel.com,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Carl Klemm <carl@...s.xyz>
Subject: Re: [PATCH v1 1/2] mm/ksm: support fork/exec for prctl

On 19.09.23 22:51, Stefan Roesch wrote:
> A process can enable KSM with the prctl system call. When the process is
> forked the KSM flag is inherited by the child process. However if the
> process is executing an exec system call directly after the fork, the
> KSM setting is cleared. This patch addresses this problem.
> 
> Signed-off-by: Stefan Roesch <shr@...kernel.io>
> Reported-by: Carl Klemm <carl@...s.xyz>
> ---
>   include/linux/sched/coredump.h | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/sched/coredump.h b/include/linux/sched/coredump.h
> index 0ee96ea7a0e9..205aa9917394 100644
> --- a/include/linux/sched/coredump.h
> +++ b/include/linux/sched/coredump.h
> @@ -87,8 +87,11 @@ static inline int get_dumpable(struct mm_struct *mm)
>   
>   #define MMF_DISABLE_THP_MASK	(1 << MMF_DISABLE_THP)
>   
> +#define MMF_VM_MERGE_ANY	29
> +#define MMF_VM_MERGE_ANY_MASK	(1 << MMF_VM_MERGE_ANY)
> +
>   #define MMF_INIT_MASK		(MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK |\
> -				 MMF_DISABLE_THP_MASK | MMF_HAS_MDWE_MASK)
> +				 MMF_DISABLE_THP_MASK | MMF_HAS_MDWE_MASK |\
> +				 MMF_VM_MERGE_ANY_MASK)
>   
> -#define MMF_VM_MERGE_ANY	29
>   #endif /* _LINUX_SCHED_COREDUMP_H */

Fixes: tag?

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

-- 
Cheers,

David / dhildenb