Unverified Commit 236924ee authored by Lukas Wunner's avatar Lukas Wunner Committed by Mark Brown
Browse files

spi: ar934x: Don't leak SPI master in probe error path 



If the call to devm_spi_register_controller() fails on probe of the
Qualcomm Atheros AR934x/QCA95xx SPI driver, the spi_controller struct is
erroneously not freed.  Fix by switching over to the new
devm_spi_alloc_master() helper.

Moreover, the controller's clock is enabled on probe but not disabled if
any of the subsequent probe steps fail.

Finally, there's an ordering issue in ar934x_spi_remove() wherein the
clock is disabled even though the controller is not yet unregistered.
It is unregistered after ar934x_spi_remove() by the devres framework.
As long as it is not unregistered, SPI transfers may still be ongoing
and disabling the clock may break them.  It is not possible to use
devm_spi_register_controller() in this case, so move to the non-devm
variant.

All of these bugs have existed since the driver was first introduced,
so it seems fair to fix them together in a single commit.

Fixes: 047980c5 ("spi: add driver for ar934x spi controller")
Signed-off-by: default avatarLukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v5.7+: 5e844cc3: spi: Introduce device-managed SPI controller allocation
Cc: <stable@vger.kernel.org> # v5.7+
Cc: Chuanhong Guo <gch981213@gmail.com>
Link: https://lore.kernel.org/r/1d58367d74d55741e0c2730a51a2b65012c8ab33.1607286887.git.lukas@wunner.de


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 46b5c4fb

drivers/spi/spi-ar934x.c

+11 −3
Original line number Diff line number Diff line
@@ -176,10 +176,11 @@ static int ar934x_spi_probe(struct platform_device *pdev) 
	if (ret)

		return ret;



	ctlr = spi_alloc_master(&pdev->dev, sizeof(*sp));

	ctlr = devm_spi_alloc_master(&pdev->dev, sizeof(*sp));

	if (!ctlr) {

		dev_info(&pdev->dev, "failed to allocate spi controller\n");

		return -ENOMEM;

		ret = -ENOMEM;

		goto err_clk_disable;

	}



	/* disable flash mapping and expose spi controller registers */
@@ -202,7 +203,13 @@ static int ar934x_spi_probe(struct platform_device *pdev) 
	sp->clk_freq = clk_get_rate(clk);

	sp->ctlr = ctlr;



	return devm_spi_register_controller(&pdev->dev, ctlr);

	ret = spi_register_controller(ctlr);

	if (!ret)

		return 0;



err_clk_disable:

	clk_disable_unprepare(clk);

	return ret;

}



static int ar934x_spi_remove(struct platform_device *pdev)
@@ -213,6 +220,7 @@ static int ar934x_spi_remove(struct platform_device *pdev) 
	ctlr = dev_get_drvdata(&pdev->dev);

	sp = spi_controller_get_devdata(ctlr);



	spi_unregister_controller(ctlr);

	clk_disable_unprepare(sp->clk);



	return 0;