[PATCH] drivers: crypto: picoxcell_crypto: Fix potential race condition bug

From: madhuparnabhowmik10@gmail.com
To: jamie@jamieiles.com, herbert@gondor.apana.org.au, davem@davemloft.net
Cc: linux-arm-kernel@lists.infradead.org,
	linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
	andrianov@ispras.ru, ldv-project@linuxtesting.org,
	Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Subject: [PATCH] drivers: crypto: picoxcell_crypto: Fix potential race condition bug
Date: Tue, 11 Aug 2020 18:00:24 +0530	[thread overview]
Message-ID: <20200811123024.14501-1-madhuparnabhowmik10@gmail.com> (raw)

From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

engine->stat_irq_thresh was initialized after device_create_file() in
the probe function, the initialization may race with call to
spacc_stat_irq_thresh_store() which updates engine->stat_irq_thresh,
therefore initialize it before creating the file in probe function.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
---
 drivers/crypto/picoxcell_crypto.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/crypto/picoxcell_crypto.c b/drivers/crypto/picoxcell_crypto.c
index dac6eb37fff9..fb34bf92861d 100644
--- a/drivers/crypto/picoxcell_crypto.c
+++ b/drivers/crypto/picoxcell_crypto.c
@@ -1685,11 +1685,6 @@ static int spacc_probe(struct platform_device *pdev)
 		goto err_clk_put;
 	}
 
-	ret = device_create_file(&pdev->dev, &dev_attr_stat_irq_thresh);
-	if (ret)
-		goto err_clk_disable;
-
-
 	/*
 	 * Use an IRQ threshold of 50% as a default. This seems to be a
 	 * reasonable trade off of latency against throughput but can be
@@ -1697,6 +1692,10 @@ static int spacc_probe(struct platform_device *pdev)
 	 */
 	engine->stat_irq_thresh = (engine->fifo_sz / 2);
 
+	ret = device_create_file(&pdev->dev, &dev_attr_stat_irq_thresh);
+	if (ret)
+		goto err_clk_disable;
+
 	/*
 	 * Configure the interrupts. We only use the STAT_CNT interrupt as we
 	 * only submit a new packet for processing when we complete another in
-- 
2.17.1

