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author | Lukas Wunner <lukas@wunner.de> | 2020-12-07 09:17:09 +0100 |
---|---|---|
committer | Mark Brown <broonie@kernel.org> | 2020-12-07 14:18:54 +0000 |
commit | 7174dc655ef0578877b0b4598e69619d2be28b4d (patch) | |
tree | 82c3c37f534d2d27694ec1fea0af916d498bb99c /drivers/spi | |
parent | 0f4ad8d59f33b24dd86739f3be23e6af1a86f5a9 (diff) | |
download | linux-7174dc655ef0578877b0b4598e69619d2be28b4d.tar.gz linux-7174dc655ef0578877b0b4598e69619d2be28b4d.tar.bz2 linux-7174dc655ef0578877b0b4598e69619d2be28b4d.zip |
spi: gpio: Don't leak SPI master in probe error path
If the call to devm_spi_register_master() fails on probe of the GPIO SPI
driver, the spi_master struct is erroneously not freed:
After allocating the spi_master, its reference count is 1. The driver
unconditionally decrements the reference count on unbind using a devm
action. Before calling devm_spi_register_master(), the driver
unconditionally increments the reference count because on success,
that function will decrement the reference count on unbind. However on
failure, devm_spi_register_master() does *not* decrement the reference
count, so the spi_master is leaked.
The issue was introduced by commits 8b797490b4db ("spi: gpio: Make sure
spi_master_put() is called in every error path") and 79567c1a321e ("spi:
gpio: Use devm_spi_register_master()"), which sought to plug leaks
introduced by 9b00bc7b901f ("spi: spi-gpio: Rewrite to use GPIO
descriptors") but missed this remaining leak.
The situation was later aggravated by commit d3b0ffa1d75d ("spi: gpio:
prevent memory leak in spi_gpio_probe"), which introduced a
use-after-free because it releases a reference on the spi_master if
devm_add_action_or_reset() fails even though the function already
does that.
Fix by switching over to the new devm_spi_alloc_master() helper.
Fixes: 9b00bc7b901f ("spi: spi-gpio: Rewrite to use GPIO descriptors")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: <stable@vger.kernel.org> # v4.17+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation
Cc: <stable@vger.kernel.org> # v5.1-: 8b797490b4db: spi: gpio: Make sure spi_master_put() is called in every error path
Cc: <stable@vger.kernel.org> # v5.1-: 45beec351998: spi: bitbang: Introduce spi_bitbang_init()
Cc: <stable@vger.kernel.org> # v5.1-: 79567c1a321e: spi: gpio: Use devm_spi_register_master()
Cc: <stable@vger.kernel.org> # v5.4-: d3b0ffa1d75d: spi: gpio: prevent memory leak in spi_gpio_probe
Cc: <stable@vger.kernel.org> # v4.17+
Cc: Navid Emamdoost <navid.emamdoost@gmail.com>
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Link: https://lore.kernel.org/r/86eaed27431c3d709e3748eb76ceecbfc790dd37.1607286887.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r-- | drivers/spi/spi-gpio.c | 15 |
1 files changed, 2 insertions, 13 deletions
diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c index 7ceb0ba27b75..0584f4d2fde2 100644 --- a/drivers/spi/spi-gpio.c +++ b/drivers/spi/spi-gpio.c @@ -350,11 +350,6 @@ static int spi_gpio_probe_pdata(struct platform_device *pdev, return 0; } -static void spi_gpio_put(void *data) -{ - spi_master_put(data); -} - static int spi_gpio_probe(struct platform_device *pdev) { int status; @@ -363,16 +358,10 @@ static int spi_gpio_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; struct spi_bitbang *bb; - master = spi_alloc_master(dev, sizeof(*spi_gpio)); + master = devm_spi_alloc_master(dev, sizeof(*spi_gpio)); if (!master) return -ENOMEM; - status = devm_add_action_or_reset(&pdev->dev, spi_gpio_put, master); - if (status) { - spi_master_put(master); - return status; - } - if (pdev->dev.of_node) status = spi_gpio_probe_dt(pdev, master); else @@ -432,7 +421,7 @@ static int spi_gpio_probe(struct platform_device *pdev) if (status) return status; - return devm_spi_register_master(&pdev->dev, spi_master_get(master)); + return devm_spi_register_master(&pdev->dev, master); } MODULE_ALIAS("platform:" DRIVER_NAME); |