linux-kernel - Re: [PATCH 2/4] mm: ksm: refer to special VMAs via VM_SPECIAL in ksm

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ab20e420-dd11-4b39-97b9-bf8041ab62fc@linux.dev>
Date: Tue, 20 May 2025 11:15:55 +0800
From: Chengming Zhou <chengming.zhou@...ux.dev>
To: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
 Andrew Morton <akpm@...ux-foundation.org>
Cc: Alexander Viro <viro@...iv.linux.org.uk>,
 Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
 "Liam R . Howlett" <Liam.Howlett@...cle.com>,
 Vlastimil Babka <vbabka@...e.cz>, Jann Horn <jannh@...gle.com>,
 Pedro Falcato <pfalcato@...e.de>, David Hildenbrand <david@...hat.com>,
 Xu Xin <xu.xin16@....com.cn>, linux-mm@...ck.org,
 linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH 2/4] mm: ksm: refer to special VMAs via VM_SPECIAL in
 ksm_compatible()

On 2025/5/19 16:51, Lorenzo Stoakes wrote:
> There's no need to spell out all the special cases, also doing it this way
> makes it absolutely clear that we preclude unmergeable VMAs in general, and
> puts the other excluded flags in stark and clear contrast.
> 
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>

Nice.

Reviewed-by: Chengming Zhou <chengming.zhou@...ux.dev>

Thanks!

> ---
>   mm/ksm.c | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/ksm.c b/mm/ksm.c
> index 08d486f188ff..d0c763abd499 100644
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -679,9 +679,8 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr, bool lock_v
>   
>   static bool ksm_compatible(const struct file *file, vm_flags_t vm_flags)
>   {
> -	if (vm_flags & (VM_SHARED   | VM_MAYSHARE   | VM_PFNMAP  |
> -			VM_IO       | VM_DONTEXPAND | VM_HUGETLB |
> -			VM_MIXEDMAP | VM_DROPPABLE))
> +	if (vm_flags & (VM_SHARED  | VM_MAYSHARE | VM_SPECIAL |
> +			VM_HUGETLB | VM_DROPPABLE))
>   		return false;		/* just ignore the advice */
>   
>   	if (file_is_dax(file))