[PATCH 5.10 645/717] spi: ar934x: Dont leak SPI master in probe error path

Greg Kroah-Hartman
2020-12-28T14:38:01Z

From: Lukas Wunner <lukas@wunner.de>

commit 236924ee531d6251c8d10e9177b7742a60534ed5 upstream.

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: 047980c582af ("spi: add driver for ar934x spi controller")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v5.7+: 5e844cc37a5c: 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: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/spi/spi-ar934x.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)

--- a/drivers/spi/spi-ar934x.c
+++ b/drivers/spi/spi-ar934x.c
@@ -176,10 +176,11 @@ static int ar934x_spi_probe(struct platf
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 platf
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 plat
ctlr = dev_get_drvdata(&pdev->dev);
sp = spi_controller_get_devdata(ctlr);

+ spi_unregister_controller(ctlr);
clk_disable_unprepare(sp->clk);

return 0;