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FAILED: patch "[PATCH] spi: bcm2835: Fix use-after-free on unbind" failed to apply to 4.9-stable tree

PATCH [email protected] 1 participant 1 message Nov 23, 2020

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Stable branch SPI Broadcom BCM2711/BCM2835 Arm architecture Broadcom BCM281XX/BCM11XXX/BCM216XX Arm architecture
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The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e1483ac030fb4c57734289742f1c1d38dca61e22 Mon Sep 17 00:00:00 2001
From: Lukas Wunner <[email protected]>
Date: Wed, 11 Nov 2020 20:07:20 +0100
Subject: [PATCH] spi: bcm2835: Fix use-after-free on unbind

bcm2835_spi_remove() accesses the driver's private data after calling spi_unregister_controller() even though that function releases the last reference on the spi_controller and thereby frees the private data.

Fix by switching over to the new devm_spi_alloc_master() helper which keeps the private data accessible until the driver has unbound.

Fixes f8043872e796 ("spi: add driver for BCM2835")
Reported-by Sascha Hauer <[email protected]>
Reported-by Florian Fainelli <[email protected]>
Signed-off-by Lukas Wunner <[email protected]>
Cc <[email protected]> # v3.10+: 123456789abc: spi: Introduce device-managed SPI controller allocation
Cc <[email protected]> # v3.10+
Cc Vladimir Oltean <[email protected]>
Tested-by Florian Fainelli <[email protected]>
Acked-by Florian Fainelli <[email protected]>
Link https://lore.kernel.org/r/ad66e0a0ad96feb848814842ecf5b6a4539ef35c.1605121038.git.lukas@wunner.de open here
Signed-off-by Mark Brown <[email protected]>
drivers/spi/spi-bcm2835.c +8 -16
index 7104cf17b848..197485f2c2b2 100644
@@ -1278,7 +1278,7 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
 	struct bcm2835_spi *bs;
 	int err;
 
-	ctlr = spi_alloc_master(&pdev->dev, ALIGN(sizeof(*bs),
+	ctlr = devm_spi_alloc_master(&pdev->dev, ALIGN(sizeof(*bs),
 						  dma_get_cache_alignment()));
 	if (!ctlr)
 		return -ENOMEM;

@@ -1299,23 +1299,17 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
 	bs->ctlr = ctlr;
 
 	bs->regs = devm_platform_ioremap_resource(pdev, 0);
-	if (IS_ERR(bs->regs)) {
-		err = PTR_ERR(bs->regs);
-		goto out_controller_put;
-	}
+	if (IS_ERR(bs->regs))
+		return PTR_ERR(bs->regs);
 
 	bs->clk = devm_clk_get(&pdev->dev, NULL);
-	if (IS_ERR(bs->clk)) {
-		err = dev_err_probe(&pdev->dev, PTR_ERR(bs->clk),
-				    "could not get clk\n");
-		goto out_controller_put;
-	}
+	if (IS_ERR(bs->clk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(bs->clk),
+				     "could not get clk\n");
 
 	bs->irq = platform_get_irq(pdev, 0);
-	if (bs->irq <= 0) {
-		err = bs->irq ? bs->irq : -ENODEV;
-		goto out_controller_put;
-	}
+	if (bs->irq <= 0)
+		return bs->irq ? bs->irq : -ENODEV;
 
 	clk_prepare_enable(bs->clk);
 

@@ -1349,8 +1343,6 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
 	bcm2835_dma_release(ctlr, bs);
 out_clk_disable:
 	clk_disable_unprepare(bs->clk);
-out_controller_put:
-	spi_controller_put(ctlr);
 	return err;
 }