From: "Danilo Krummrich" <dakr@kernel.org>
To: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>
Cc: <driver-core@lists.linux.dev>, <linux-kernel@vger.kernel.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
"NeilBrown" <neil@brown.name>, "Tejun Heo" <tj@kernel.org>
Subject: Re: [PATCH] sysfs: clamp show() return value in sysfs_kf_read()
Date: Wed, 20 May 2026 16:43:42 +0200 [thread overview]
Message-ID: <DINL18ZHVV2F.390OXFCNKGDA2@kernel.org> (raw)
In-Reply-To: <2026052000-drove-unicycle-d61b@gregkh>
On Wed May 20, 2026 at 3:07 PM CEST, Greg Kroah-Hartman wrote:
> sysfs_kf_seq_show() defends against buggy show() callbacks that return
> larger than PAGE_SIZE by clamping the value and printing a warning.
> sysfs_kf_read(), the prealloc variant, has no such defense.
>
> The only current in-tree user of __ATTR_PREALLOC is drivers/md/md.c,
> whose show() callbacks are well-behaved, so this is hardening against
> future drivers doing foolish things and out-of-tree code doing even more
> foolish things.
>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Danilo Krummrich <dakr@kernel.org>
> Cc: NeilBrown <neil@brown.name>
> Cc: Tejun Heo <tj@kernel.org>
> Fixes: 2b75869bba67 ("sysfs/kernfs: allow attributes to request write buffer be pre-allocated.")
> Assisted-by: gregkh_clanker_t1000
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
next prev parent reply other threads:[~2026-05-20 14:43 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-20 13:07 [PATCH] sysfs: clamp show() return value in sysfs_kf_read() Greg Kroah-Hartman
2026-05-20 13:36 ` Rafael J. Wysocki
2026-05-20 14:43 ` Danilo Krummrich [this message]
2026-05-20 18:19 ` Tejun Heo
2026-05-21 6:18 ` Greg Kroah-Hartman
2026-05-21 10:04 ` David Laight
2026-05-21 16:18 ` Tejun Heo
2026-05-21 21:42 ` David Laight
2026-05-20 22:11 ` David Laight
2026-05-21 6:19 ` Greg Kroah-Hartman
2026-05-21 9:17 ` David Laight
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