hwrng: imx-rngc - Moving IRQ handler registering after imx_rngc_irq_m…

…ask_clear()

[ Upstream commit 10a2199 ]

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: 1d54494 (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

@@ -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) {