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From: Markus Elfring <Markus.Elfring@web.de>
To: Lee Jones <lee@kernel.org>,
	linux-input@vger.kernel.org,
	Benjamin Tissoires <bentiss@kernel.org>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Jason Gerecke <jason.gerecke@wacom.com>,
	Jiri Kosina <jikos@kernel.org>,
	Peter Hutterer <peter.hutterer@who-t.net>,
	Ping Cheng <ping.cheng@wacom.com>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/2] HID: wacom: Fix Use-After-Free in wacom_intuos_pad
Date: Mon, 1 Jun 2026 16:48:10 +0200	[thread overview]
Message-ID: <94726c18-71d0-4cae-89e7-eeece38283da@web.de> (raw)
In-Reply-To: <20260601140845.1237227-1-lee@kernel.org>

…
> +++ b/drivers/hid/wacom_sys.c
> @@ -877,10 +877,16 @@ static void wacom_remove_shared_data(void *res)
>  		data = container_of(wacom_wac->shared, struct wacom_hdev_data,
>  				    shared);
>  
> -		if (wacom_wac->shared->touch == wacom->hdev)
> +		mutex_lock(&wacom_udev_list_lock);
> +		if (wacom_wac->shared->touch == wacom->hdev) {
>  			wacom_wac->shared->touch = NULL;
> +		}
> +		mutex_unlock(&wacom_udev_list_lock);
> +
> +		synchronize_rcu();
>  
>  		kref_put(&data->kref, wacom_release_shared_data);
…

Under which circumstances would you dare to apply another lock guard?
https://elixir.bootlin.com/linux/v7.1-rc5/source/include/linux/mutex.h#L253

Regards,
Markus

      parent reply	other threads:[~2026-06-01 14:48 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-01 14:08 Lee Jones
2026-06-01 14:08 ` [PATCH v2 2/2] HID: wacom: Redesign shared sibling data lifecycle Lee Jones
2026-06-01 14:48 ` Markus Elfring [this message]

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