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Subject[PATCH 5.9 004/152] spi: bcm2835: Fix use-after-free on unbind
Date
From: Lukas Wunner <lukas@wunner.de>

commit e1483ac030fb4c57734289742f1c1d38dca61e22 upstream

bcm2835_spi_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: f8043872e796 ("spi: add driver for BCM2835")
Reported-by: Sascha Hauer <s.hauer@pengutronix.de>
Reported-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v3.10+: 123456789abc: spi: Introduce device-managed SPI controller allocation
Cc: <stable@vger.kernel.org> # v3.10+
Cc: Vladimir Oltean <olteanv@gmail.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/ad66e0a0ad96feb848814842ecf5b6a4539ef35c.1605121038.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/spi/spi-bcm2835.c | 27 ++++++++-------------------
1 file changed, 8 insertions(+), 19 deletions(-)

--- a/drivers/spi/spi-bcm2835.c
+++ b/drivers/spi/spi-bcm2835.c
@@ -1278,7 +1278,7 @@ static int bcm2835_spi_probe(struct plat
struct bcm2835_spi *bs;
int err;

- ctlr = spi_alloc_master(&pdev->dev, ALIGN(sizeof(*bs),
+ ctlr = devm_spi_alloc_master(&pdev->dev, ALIGN(sizeof(*bs),
dma_get_cache_alignment()));
if (!ctlr)
return -ENOMEM;
@@ -1299,26 +1299,17 @@ static int bcm2835_spi_probe(struct plat
bs->ctlr = ctlr;

bs->regs = devm_platform_ioremap_resource(pdev, 0);
- if (IS_ERR(bs->regs)) {
- err = PTR_ERR(bs->regs);
- goto out_controller_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);
- if (err == -EPROBE_DEFER)
- dev_dbg(&pdev->dev, "could not get clk: %d\n", err);
- else
- dev_err(&pdev->dev, "could not get clk: %d\n", err);
- goto out_controller_put;
- }
+ if (IS_ERR(bs->clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(bs->clk),
+ "could not get clk\n");

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

clk_prepare_enable(bs->clk);

@@ -1352,8 +1343,6 @@ out_dma_release:
bcm2835_dma_release(ctlr, bs);
out_clk_disable:
clk_disable_unprepare(bs->clk);
-out_controller_put:
- spi_controller_put(ctlr);
return err;
}


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