linux-kernel - [PATCH 4.9 001/177] mfd: fsl-imx25: Clean up irq settings during removal

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Date:   Mon, 18 Dec 2017 16:47:04 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Martin Kaiser <martin@...ser.cx>,
        Lucas Stach <l.stach@...gutronix.de>,
        Lee Jones <lee.jones@...aro.org>
Subject: [PATCH 4.9 001/177] mfd: fsl-imx25: Clean up irq settings during removal

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Martin Kaiser <martin@...ser.cx>

commit 18f77393796848e68909e65d692c1d1436f06e06 upstream.

When fsl-imx25-tsadc is compiled as a module, loading, unloading and
reloading the module will lead to a crash.

Unable to handle kernel paging request at virtual address bf005430
[<c004df6c>] (irq_find_matching_fwspec)
   from [<c028d5ec>] (of_irq_get+0x58/0x74)
[<c028d594>] (of_irq_get)
   from [<c01ff970>] (platform_get_irq+0x48/0xc8)
[<c01ff928>] (platform_get_irq)
   from [<bf00e33c>] (mx25_tsadc_probe+0x220/0x2f4 [fsl_imx25_tsadc])

irq_find_matching_fwspec() loops over all registered irq domains. The
irq domain is still registered from last time the module was loaded but
the pointer to its operations is invalid after the module was unloaded.

Add a removal function which clears the irq handler and removes the irq
domain. With this cleanup in place, it's possible to unload and reload
the module.

Signed-off-by: Martin Kaiser <martin@...ser.cx>
Reviewed-by: Lucas Stach <l.stach@...gutronix.de>
Signed-off-by: Lee Jones <lee.jones@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/mfd/fsl-imx25-tsadc.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

--- a/drivers/mfd/fsl-imx25-tsadc.c
+++ b/drivers/mfd/fsl-imx25-tsadc.c
@@ -183,6 +183,19 @@ static int mx25_tsadc_probe(struct platf
 	return 0;
 }
 
+static int mx25_tsadc_remove(struct platform_device *pdev)
+{
+	struct mx25_tsadc *tsadc = platform_get_drvdata(pdev);
+	int irq = platform_get_irq(pdev, 0);
+
+	if (irq) {
+		irq_set_chained_handler_and_data(irq, NULL, NULL);
+		irq_domain_remove(tsadc->domain);
+	}
+
+	return 0;
+}
+
 static const struct of_device_id mx25_tsadc_ids[] = {
 	{ .compatible = "fsl,imx25-tsadc" },
 	{ /* Sentinel */ }
@@ -194,6 +207,7 @@ static struct platform_driver mx25_tsadc
 		.of_match_table = of_match_ptr(mx25_tsadc_ids),
 	},
 	.probe = mx25_tsadc_probe,
+	.remove = mx25_tsadc_remove,
 };
 module_platform_driver(mx25_tsadc_driver);