[PATCH 5.10 643/717] spi: atmel-quadspi: Fix use-after-free on unbind

Greg Kroah-Hartman
2020-12-28T14:31:43Z

From: Lukas Wunner <lukas@wunner.de>

commit c7b884561cb5b641f3dbba950094110794119a6d upstream.

atmel_qspi_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: 2d30ac5ed633 ("mtd: spi-nor: atmel-quadspi: Use spi-mem interface for atmel-quadspi driver")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v5.0+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation
Cc: <stable@vger.kernel.org> # v5.0+
Cc: Piotr Bugalski <bugalski.piotr@gmail.com>
Link: https://lore.kernel.org/r/4b05c65cf6f1ea3251484fe9a00b4c65478a1ae3.1607286887.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/spi/atmel-quadspi.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)

--- a/drivers/spi/atmel-quadspi.c
+++ b/drivers/spi/atmel-quadspi.c
@@ -535,7 +535,7 @@ static int atmel_qspi_probe(struct platf
struct resource *res;
int irq, err = 0;

- ctrl = spi_alloc_master(&pdev->dev, sizeof(*aq));
+ ctrl = devm_spi_alloc_master(&pdev->dev, sizeof(*aq));
if (!ctrl)
return -ENOMEM;

@@ -557,8 +557,7 @@ static int atmel_qspi_probe(struct platf
aq->regs = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(aq->regs)) {
dev_err(&pdev->dev, "missing registers\n");
- err = PTR_ERR(aq->regs);
- goto exit;
+ return PTR_ERR(aq->regs);
}

/* Map the AHB memory */
@@ -566,8 +565,7 @@ static int atmel_qspi_probe(struct platf
aq->mem = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(aq->mem)) {
dev_err(&pdev->dev, "missing AHB memory\n");
- err = PTR_ERR(aq->mem);
- goto exit;
+ return PTR_ERR(aq->mem);
}

aq->mmap_size = resource_size(res);
@@ -579,15 +577,14 @@ static int atmel_qspi_probe(struct platf

if (IS_ERR(aq->pclk)) {
dev_err(&pdev->dev, "missing peripheral clock\n");
- err = PTR_ERR(aq->pclk);
- goto exit;
+ return PTR_ERR(aq->pclk);
}

/* Enable the peripheral clock */
err = clk_prepare_enable(aq->pclk);
if (err) {
dev_err(&pdev->dev, "failed to enable the peripheral clock\n");
- goto exit;
+ return err;
}

aq->caps = of_device_get_match_data(&pdev->dev);
@@ -638,8 +635,6 @@ disable_qspick:
clk_disable_unprepare(aq->qspick);
disable_pclk:
clk_disable_unprepare(aq->pclk);
-exit:
- spi_controller_put(ctrl);

return err;
}