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smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=DuyZcDLB; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B9B56606A319 for ; Tue, 20 Oct 2026 08:18:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=DuyZcDLB Received: by smtp.kernel.org (Postfix) with ESMTPSA id 878311F000C4; Tue, 20 Oct 2026 08:18:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792484307; bh=rhd9i6MZ/tSeH3TKysGHa5PRQgjZlpMeCGZ/ilQN7u4=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=DuyZcDLBfXNWGZLzrjjSwNI0RzkczO2f3zpg9vZGZFaS9pACw8aG3t0ARdAuQvUpJ Y0yKh/MRIGouMTXjxlKTSRaT6iXqHy71ZAbQXpZ9MkolrGsHxKh/dr/OX1/4OMSeQd 8Igv/fmXqVZP1lAGUC08nLriQ983EoBLSu9HIRMP3ZScQWfvC0afHppbX81k0ZFnEr TI1vDWFtseK9Dfpk7vRuXTWYPHawurc49SNlwPBVNrosNDt+prbwGFkSHmFlmVRYgQ tux4Gr+NELTlqmf4DbsgcToRnH0obdgf52u7zp6K/OETHTxV3DpRhRN2JvX9TbaFM/ /XwIgnp+F4UPg== Message-ID: Date: Tue, 20 Oct 2026 10:18:23 +0200 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V2 1/3] mm/hugetlb: fix mremap move length truncation To: Li Zhe , muchun.song@linux.dev, osalvador@suse.de, akpm@linux-foundation.org, rppt@kernel.org, peterx@redhat.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20261019113034.97690-1-lizhe.67@bytedance.com> <20261019113034.97690-2-lizhe.67@bytedance.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/19/26 13:30, Li Zhe wrote: > move_hugetlb_page_tables() returns the number of bytes moved, but > its return type is int while the generic move_page_tables() path uses > unsigned long lengths. > > A hugetlb mremap() move length above INT_MAX can therefore be > misreported to copy_vma_and_data(). The out-of-range conversion to int > is implementation-defined; on common 64-bit builds, for example, a > 4 GiB move can be reported as zero, making the caller treat the move as > a failure and use the wrong length for rollback. Sounds like we want to CC stable here, right? > > Return unsigned long from move_hugetlb_page_tables(), matching > move_page_tables() and preserving the full byte count. > > Fixes: 550a7d60bd5e ("mm, hugepages: add mremap() support for hugepage backed vma") > Signed-off-by: Li Zhe > --- > include/linux/hugetlb.h | 18 +++++++++--------- > mm/hugetlb.c | 8 ++++---- > 2 files changed, 13 insertions(+), 13 deletions(-) > > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index 16c4c4caa126..cc12040e4032 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -121,10 +121,10 @@ void hugepage_put_subpool(struct hugepage_subpool *spool); > > void hugetlb_dup_vma_private(struct vm_area_struct *vma); > void clear_vma_resv_huge_pages(struct vm_area_struct *vma); > -int move_hugetlb_page_tables(struct vm_area_struct *vma, > - struct vm_area_struct *new_vma, > - unsigned long old_addr, unsigned long new_addr, > - unsigned long len); > +unsigned long move_hugetlb_page_tables(struct vm_area_struct *vma, > + struct vm_area_struct *new_vma, > + unsigned long old_addr, unsigned long new_addr, > + unsigned long len); While at it, can you convert all these to use double tab indent instead? Acked-by: David Hildenbrand (Arm) -- Cheers, David