From: William Breathitt Gray <wbg@kernel.org>
To: William Breathitt Gray <william.gray@linaro.org>
Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH] counter: 104-quad-8: Fix race getting function mode and direction
Date: Sat, 22 Oct 2022 11:11:57 -0400 [thread overview]
Message-ID: <Y1QIPTIxjo9rDF/I@ishi> (raw)
In-Reply-To: <20221020141121.15434-1-william.gray@linaro.org>
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On Thu, Oct 20, 2022 at 10:11:21AM -0400, William Breathitt Gray wrote:
> The quad8_action_read() function checks the Count function mode and
> Count direction without first acquiring a lock. This is a race condition
> because the function mode could change by the time the direction is
> checked.
>
> Because the quad8_function_read() already acquires a lock internally,
> the quad8_function_read() is refactored to spin out the no-lock code to
> a new quad8_function_get() function.
>
> To resolve the race condition in quad8_action_read(), a lock is acquired
> before calling quad8_function_get() and quad8_direction_read() in order
> to get both function mode and direction atomically.
>
> Fixes: f1d8a071d45b ("counter: 104-quad-8: Add Generic Counter interface support")
> Cc: stable@vger.kernel.org
> Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Queued for counter-fixes.
William Breathitt Gray
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prev parent reply other threads:[~2022-10-22 15:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-20 14:11 [PATCH] counter: 104-quad-8: Fix race getting function mode and direction William Breathitt Gray
2022-10-22 15:11 ` William Breathitt Gray [this message]
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