linux-kernel - Re: [PATCH v2] mm/shmem, swap: fix race of truncate and swap entry split

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Message-ID: <CAMgjq7Bw9Ascd5FdTg=wf8dHtQN2n=cJPqREsatBJPoDLJVG=Q@mail.gmail.com>
Date: Mon, 19 Jan 2026 11:17:12 +0800
From: Kairui Song <ryncsn@...il.com>
To: Baolin Wang <baolin.wang@...ux.alibaba.com>
Cc: linux-mm@...ck.org, Hugh Dickins <hughd@...gle.com>, 
	Andrew Morton <akpm@...ux-foundation.org>, Kemeng Shi <shikemeng@...weicloud.com>, 
	Nhat Pham <nphamcs@...il.com>, Chris Li <chrisl@...nel.org>, Baoquan He <bhe@...hat.com>, 
	Barry Song <baohua@...nel.org>, linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH v2] mm/shmem, swap: fix race of truncate and swap entry split

On Mon, Jan 19, 2026 at 11:04 AM Baolin Wang
<baolin.wang@...ux.alibaba.com> wrote:
> On 1/19/26 12:55 AM, Kairui Song wrote:
> > From: Kairui Song <kasong@...cent.com>
> >
> >                               if (!swaps_freed) {
> > +                                     /*
> > +                                      * If found a large swap entry cross the end border,
> > +                                      * skip it as the truncate_inode_partial_folio above
> > +                                      * should have at least zerod its content once.
> > +                                      */
> > +                                     order = shmem_confirm_swap(mapping, indices[i],
> > +                                                                radix_to_swp_entry(folio));
> > +                                     if (order > 0 && indices[i] + order > end)
> > +                                             continue;
>
> The latter check shoud be 'indices[i] + 1 << order > end', right?

Yes, you are right, it should be 1 << order, thanks!