linux-kernel - Re: [PATCH v1 1/5] f2fs: Zero f2fs_folio

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: <CAGsJ_4yrspqjbEK8vj8Fd9FCDAasQ7mp5nBsE0Zg9XX265PXgA@mail.gmail.com>
Date: Tue, 6 Jan 2026 11:38:49 +0800
From: Barry Song <21cnbao@...il.com>
To: Nanzhe Zhao <nzzhao@....com>
Cc: Kim Jaegeuk <jaegeuk@...nel.org>, Chao Yu <chao@...nel.org>, 
	linux-f2fs-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 1/5] f2fs: Zero f2fs_folio_state on allocation

On Tue, Jan 6, 2026 at 12:12 AM Nanzhe Zhao <nzzhao@....com> wrote:
>
> f2fs_folio_state is attached to folio->private and is expected to start
> with read_pages_pending == 0.  However, the structure was allocated from
> ffs_entry_slab without being fully initialized, which can leave
> read_pages_pending with stale values.
>
> Allocate the object with __GFP_ZERO so all fields are reliably zeroed at
> creation time.
>
> Signed-off-by: Nanzhe Zhao <nzzhao@....com>


We already have GFP_F2FS_ZERO, but it includes GFP_IO. Should we
introduce another variant, such as GFP_F2FS_NOIO_ZERO (or similar)?
Overall, LGTM.

Reviewed-by: Barry Song <baohua@...nel.org>

> ---
>  fs/f2fs/data.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 471e52c6c1e0..ab091b294fa7 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -2389,7 +2389,7 @@ static struct f2fs_folio_state *ffs_find_or_alloc(struct folio *folio)
>         if (ffs)
>                 return ffs;
>
> -       ffs = f2fs_kmem_cache_alloc(ffs_entry_slab, GFP_NOIO, true, NULL);
> +       ffs = f2fs_kmem_cache_alloc(ffs_entry_slab, GFP_NOIO | __GFP_ZERO, true, NULL);
>
>         spin_lock_init(&ffs->state_lock);
>         folio_attach_private(folio, ffs);
> --
> 2.34.1

Thanks
Barry