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Date: Wed, 17 Jan 2024 06:44:40 +0100
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: "Christian A. Ehrhardt" <lk@c--e.de>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>,
	linux-usb@vger.kernel.org, Dell.Client.Kernel@dell.com,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Hans de Goede <hdegoede@redhat.com>,
	Jack Pham <quic_jackp@quicinc.com>,
	Fabrice Gasnier <fabrice.gasnier@foss.st.com>,
	Samuel =?utf-8?B?xIxhdm9q?= <samuel@cavoj.net>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] usb: ucsi: Add missing ppm_lock
Message-ID: <2024011726-exhaust-writing-29d4@gregkh>
References: <20240116224041.220740-1-lk@c--e.de>
 <20240116224041.220740-2-lk@c--e.de>
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In-Reply-To: <20240116224041.220740-2-lk@c--e.de>

On Tue, Jan 16, 2024 at 11:40:39PM +0100, Christian A. Ehrhardt wrote:
> Calling ->sync_write must be done while holding the PPM lock as the
> mailbox logic does not support concurrent commands.
> 
> Thus protect the only call to ucsi_acknowledge_connector_change
> with the PPM lock as it calls ->sync_write. All other calls to
> ->sync_write already happen under the PPM lock.
> 
> Signed-off-by: Christian A. Ehrhardt <lk@c--e.de>
> ---
> NOTE: This is not a theoretical issue. I've seen problems resulting
> from the missing lock on real hardware.

What commit id does this fix?

Should it be cc: stable?

thanks,

greg k-h