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

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Message-Id: <20201228125051.838378190@linuxfoundation.org>
Date:   Mon, 28 Dec 2020 13:50:43 +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, Lukas Wunner <lukas@...ner.de>,
        Chuanhong Guo <gch981213@...il.com>,
        Mark Brown <broonie@...nel.org>
Subject: [PATCH 5.10 645/717] spi: ar934x: Dont leak SPI master in probe error path

From: Lukas Wunner <lukas@...ner.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@...ner.de>
Cc: <stable@...r.kernel.org> # v5.7+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation
Cc: <stable@...r.kernel.org> # v5.7+
Cc: Chuanhong Guo <gch981213@...il.com>
Link: https://lore.kernel.org/r/1d58367d74d55741e0c2730a51a2b65012c8ab33.1607286887.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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;