spi: bcm2835aux: Fix use-after-free on unbind (e13ee6cc) · Commits · 戴 / test

bcm2835aux_spi_remove() accesses the driver's private data after calling spi_unregister_master() even though that function releases the last reference on the spi_master 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: ("spi: bcm2835aux: Fix controller unregister order") Signed-off-by:

Lukas Wunner <lukas@wunner.de> Cc: <stable@vger.kernel.org> # v4.4+: 123456789abc: spi: Introduce device-managed SPI controller allocation Cc: <stable@vger.kernel.org> # v4.4+: : spi: bcm2835aux: Fix controller unregister order Cc: <stable@vger.kernel.org> # v4.4+ Link: https://lore.kernel.org/r/b290b06357d0c0bdee9cecc539b840a90630f101.1605121038.git.lukas@wunner.de Signed-off-by:

Mark Brown <broonie@kernel.org>

drivers/spi/spi-bcm2835aux.c

+7 −14

Original line number	Diff line number	Diff line
		@@ -494,7 +494,7 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev)
		unsigned long clk_hz;
		int err;

		master = spi_alloc_master(&pdev->dev, sizeof(*bs));
		master = devm_spi_alloc_master(&pdev->dev, sizeof(*bs));
		if (!master)
		return -ENOMEM;

		@@ -524,29 +524,24 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev)

		/* the main area */
		bs->regs = devm_platform_ioremap_resource(pdev, 0);
		if (IS_ERR(bs->regs)) {
		err = PTR_ERR(bs->regs);
		goto out_master_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 = PTR_ERR(bs->clk);
		dev_err(&pdev->dev, "could not get clk: %d\n", err);
		goto out_master_put;
		return PTR_ERR(bs->clk);
		}

		bs->irq = platform_get_irq(pdev, 0);
		if (bs->irq <= 0) {
		err = bs->irq ? bs->irq : -ENODEV;
		goto out_master_put;
		}
		if (bs->irq <= 0)
		return bs->irq ? bs->irq : -ENODEV;

		/* this also enables the HW block */
		err = clk_prepare_enable(bs->clk);
		if (err) {
		dev_err(&pdev->dev, "could not prepare clock: %d\n", err);
		goto out_master_put;
		return err;
		}

		/* just checking if the clock returns a sane value */
		@@ -581,8 +576,6 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev)

		out_clk_disable:
		clk_disable_unprepare(bs->clk);
		out_master_put:
		spi_master_put(master);
		return err;
		}

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