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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,
        Kshitiz Varshney <kshitiz.varshney@nxp.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.0 630/862] hwrng: imx-rngc - Moving IRQ handler registering after imx_rngc_irq_mask_clear()
Date:   Wed, 19 Oct 2022 10:31:57 +0200
Message-Id: <20221019083317.756212832@linuxfoundation.org>
In-Reply-To: <20221019083249.951566199@linuxfoundation.org>
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From: Kshitiz Varshney <kshitiz.varshney@nxp.com>

[ Upstream commit 10a2199caf437e893d9027d97700b3c6010048b7 ]

Issue:
While servicing interrupt, if the IRQ happens to be because of a SEED_DONE
due to a previous boot stage, you end up completing the completion
prematurely, hence causing kernel to crash while booting.

Fix:
Moving IRQ handler registering after imx_rngc_irq_mask_clear()

Fixes: 1d5449445bd0 (hwrng: mx-rngc - add a driver for Freescale RNGC)
Signed-off-by: Kshitiz Varshney <kshitiz.varshney@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/char/hw_random/imx-rngc.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c
index e32c52c10d4d..1d7ce7443586 100644
--- a/drivers/char/hw_random/imx-rngc.c
+++ b/drivers/char/hw_random/imx-rngc.c
@@ -264,13 +264,6 @@ static int imx_rngc_probe(struct platform_device *pdev)
 	if (rng_type != RNGC_TYPE_RNGC && rng_type != RNGC_TYPE_RNGB)
 		return -ENODEV;
 
-	ret = devm_request_irq(&pdev->dev,
-			irq, imx_rngc_irq, 0, pdev->name, (void *)rngc);
-	if (ret) {
-		dev_err(rngc->dev, "Can't get interrupt working.\n");
-		return ret;
-	}
-
 	init_completion(&rngc->rng_op_done);
 
 	rngc->rng.name = pdev->name;
@@ -284,6 +277,13 @@ static int imx_rngc_probe(struct platform_device *pdev)
 
 	imx_rngc_irq_mask_clear(rngc);
 
+	ret = devm_request_irq(&pdev->dev,
+			irq, imx_rngc_irq, 0, pdev->name, (void *)rngc);
+	if (ret) {
+		dev_err(rngc->dev, "Can't get interrupt working.\n");
+		return ret;
+	}
+
 	if (self_test) {
 		ret = imx_rngc_self_test(rngc);
 		if (ret) {
-- 
2.35.1