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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        =?UTF-8?q?Timo=20Schl=C3=BC=C3=9Fler?= <schluessler@krause.de>,
        Marc Kleine-Budde <mkl@pengutronix.de>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 035/321] can: mcp251x: mcp251x_restart_work_handler(): Fix potential force_quit race condition
Date:   Tue,  3 Dec 2019 23:31:41 +0100
Message-Id: <20191203223428.940510843@linuxfoundation.org>
In-Reply-To: <20191203223427.103571230@linuxfoundation.org>
References: <20191203223427.103571230@linuxfoundation.org>
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From: Timo Schlüßler <schluessler@krause.de>

[ Upstream commit 27a0e54bae09d2dd023a01254db506d61cc50ba1 ]

In mcp251x_restart_work_handler() the variable to stop the interrupt
handler (priv->force_quit) is reset after the chip is restarted and thus
a interrupt might occur.

This patch fixes the potential race condition by resetting force_quit
before enabling interrupts.

Signed-off-by: Timo Schlüßler <schluessler@krause.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/can/spi/mcp251x.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
index de8d9dceb1236..0b0dd3f096dc6 100644
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -773,6 +773,7 @@ static void mcp251x_restart_work_handler(struct work_struct *ws)
 	if (priv->after_suspend) {
 		mcp251x_hw_reset(spi);
 		mcp251x_setup(net, spi);
+		priv->force_quit = 0;
 		if (priv->after_suspend & AFTER_SUSPEND_RESTART) {
 			mcp251x_set_normal_mode(spi);
 		} else if (priv->after_suspend & AFTER_SUSPEND_UP) {
@@ -784,7 +785,6 @@ static void mcp251x_restart_work_handler(struct work_struct *ws)
 			mcp251x_hw_sleep(spi);
 		}
 		priv->after_suspend = 0;
-		priv->force_quit = 0;
 	}
 
 	if (priv->restart_tx) {
-- 
2.20.1