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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,
        Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>,
        Jamie Iles <jamie@jamieiles.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.8 105/633] crypto: picoxcell - Fix potential race condition bug
Date:   Tue, 27 Oct 2020 14:47:28 +0100
Message-Id: <20201027135527.606837533@linuxfoundation.org>
In-Reply-To: <20201027135522.655719020@linuxfoundation.org>
References: <20201027135522.655719020@linuxfoundation.org>
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From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

[ Upstream commit 64f4a62e3b17f1e473f971127c2924cae42afc82 ]

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).

Fixes: ce92136843cb ("crypto: picoxcell - add support for the...")
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Acked-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 7384e91c8b32b..0d32b641a7f9d 100644
--- a/drivers/crypto/picoxcell_crypto.c
+++ b/drivers/crypto/picoxcell_crypto.c
@@ -1666,11 +1666,6 @@ 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
@@ -1678,6 +1673,10 @@ 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
-- 
2.25.1