From: Lance Yang <lance.yang@linux.dev>
To: Ye Liu <ye.liu@linux.dev>
Cc: Ye Liu <liuye@kylinos.cn>, Zi Yan <ziy@nvidia.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
"Liam R. Howlett" <liam@infradead.org>,
Nico Pache <npache@redhat.com>, Xin Hao <xhao@linux.alibaba.com>,
Lorenzo Stoakes <ljs@kernel.org>,
David Hildenbrand <david@kernel.org>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Barry Song <baohua@kernel.org>,
Andrew Morton <akpm@linux-foudation.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] mm/khugepaged: fix inconsistent MMF_VM_HUGEPAGE flag due to allocation failure order
Date: Mon, 11 May 2026 11:11:16 +0800 [thread overview]
Message-ID: <49787989-f05f-4e2c-bbad-bd8fa0e19dff@linux.dev> (raw)
In-Reply-To: <20260511025408.54035-1-ye.liu@linux.dev>
On 2026/5/11 10:54, Ye Liu wrote:
> From: Ye Liu <liuye@kylinos.cn>
>
> __khugepaged_enter() sets MMF_VM_HUGEPAGE before allocating the
> corresponding mm_slot. If mm_slot_alloc() fails, the function
> returns with the flag set but without inserting the mm into the
> khugepaged tracking structures, leaving the mm in an inconsistent
> state where future registration attempts are skipped.
>
> Fix this by reordering: allocate the mm_slot first, then check and
> set the flag. If the flag is already set, free the allocated slot
> and return. This ensures the flag is only set when the mm is
> successfully registered in the khugepaged tracking structures.
>
> Fixes: 16618670276a ("mm: khugepaged: avoid pointless allocation for "struct mm_slot"")
> Suggested-by: David Hildenbrand <david@kernel.org>
> Signed-off-by: Ye Liu <liuye@kylinos.cn>
> ---
LGTM, thanks.
Reviewed-by: Lance Yang <lance.yang@linux.dev>
next prev parent reply other threads:[~2026-05-11 3:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-11 2:54 [PATCH v3] mm/khugepaged: fix inconsistent MMF_VM_HUGEPAGE flag due to allocation failure order Ye Liu
2026-05-11 3:11 ` Lance Yang [this message]
2026-05-11 5:41 ` David Hildenbrand (Arm)
2026-05-11 5:45 ` Dev Jain
2026-05-11 14:20 ` Lorenzo Stoakes
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