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From:   Arnd Bergmann <arnd@arndb.de>
To:     Thomas Gleixner <tglx@linutronix.de>,
        Jason Cooper <jason@lakedaemon.net>,
        Marc Zyngier <marc.zyngier@arm.com>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Lucas Stach <l.stach@pengutronix.de>,
        Aisheng Dong <aisheng.dong@nxp.com>,
        Fugang Duan <fugang.duan@nxp.com>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH] irqchip/imx-irqsteer: fix of_property_read_u32() error handling
Date:   Mon,  4 Mar 2019 21:02:18 +0100
Message-Id: <20190304200245.1196001-1-arnd@arndb.de>
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Sender: linux-kernel-owner@vger.kernel.org
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gcc points out that irqs_num is not initialized when of_property_read_u32()
is an empty stub function:

                 Included from drivers/irqchip/irq-imx-irqsteer.c:7:
drivers/irqchip/irq-imx-irqsteer.c: In function 'imx_irqsteer_probe':
include/uapi/linux/kernel.h:13:49: error: 'irqs_num' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The same can actually happen with CONFIG_OF=y as well, though we don't
get a warning then.

Add error checking here that lets the code deal with missing or
invalid properties as well as avoid the warning.

Fixes: 28528fca4908 ("irqchip/imx-irqsteer: Add multi output interrupts support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/irqchip/irq-imx-irqsteer.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-imx-irqsteer.c b/drivers/irqchip/irq-imx-irqsteer.c
index d1098f4da6a4..88df3d00052c 100644
--- a/drivers/irqchip/irq-imx-irqsteer.c
+++ b/drivers/irqchip/irq-imx-irqsteer.c
@@ -169,8 +169,12 @@ static int imx_irqsteer_probe(struct platform_device *pdev)
 
 	raw_spin_lock_init(&data->lock);
 
-	of_property_read_u32(np, "fsl,num-irqs", &irqs_num);
-	of_property_read_u32(np, "fsl,channel", &data->channel);
+	ret = of_property_read_u32(np, "fsl,num-irqs", &irqs_num);
+	if (ret)
+		return ret;
+	ret = of_property_read_u32(np, "fsl,channel", &data->channel);
+	if (ret)
+		return ret;
 
 	/*
 	 * There is one output irq for each group of 64 inputs.
-- 
2.20.0