From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 98C9A79CE for ; Thu, 12 Jan 2023 14:22:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F27FAC433EF; Thu, 12 Jan 2023 14:22:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673533332; bh=o5nzefQ57P0Alntez8GQ8sqj3xfYsvHSV2a1raD9Ab0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dywtstdShVPCSKlqpwNc0KvxxFGrsUFxWDn1Boh8vXlWptUam03s4gOGxaTaCLQS0 APb45bKDA3/LJ/vVQvPh3y2yug8b8szSgwuus6VTFBGmb46yukHl6m4iq2S6SqystS z/wowrlJbmo7q+DZrsCpoZ0+OYtdMTJsRj319uYw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Emil Renner Berthing , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Thierry Reding , Sasha Levin Subject: [PATCH 5.10 445/783] pwm: sifive: Call pwm_sifive_update_clock() while mutex is held Date: Thu, 12 Jan 2023 14:52:41 +0100 Message-Id: <20230112135544.884489665@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230112135524.143670746@linuxfoundation.org> References: <20230112135524.143670746@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Uwe Kleine-König [ Upstream commit 45558b3abb87eeb2cedb8a59cb2699c120b5102a ] As was documented in commit 0f02f491b786 ("pwm: sifive: Reduce time the controller lock is held") a caller of pwm_sifive_update_clock() must hold the mutex. So fix pwm_sifive_clock_notifier() to grab the lock. While this necessity was only documented later, the race exists since the driver was introduced. Fixes: 9e37a53eb051 ("pwm: sifive: Add a driver for SiFive SoC PWM") Reported-by: Emil Renner Berthing Reviewed-by: Emil Renner Berthing Link: https://lore.kernel.org/r/20221018061656.1428111-1-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König Signed-off-by: Thierry Reding Signed-off-by: Sasha Levin --- drivers/pwm/pwm-sifive.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c index 9cc0612f0849..12e9e23272ab 100644 --- a/drivers/pwm/pwm-sifive.c +++ b/drivers/pwm/pwm-sifive.c @@ -217,8 +217,11 @@ static int pwm_sifive_clock_notifier(struct notifier_block *nb, struct pwm_sifive_ddata *ddata = container_of(nb, struct pwm_sifive_ddata, notifier); - if (event == POST_RATE_CHANGE) + if (event == POST_RATE_CHANGE) { + mutex_lock(&ddata->lock); pwm_sifive_update_clock(ddata, ndata->new_rate); + mutex_unlock(&ddata->lock); + } return NOTIFY_OK; } -- 2.35.1