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authorLukas Wunner <lukas@wunner.de>2020-12-07 09:17:09 +0100
committerMark Brown <broonie@kernel.org>2020-12-07 14:18:54 +0000
commit7174dc655ef0578877b0b4598e69619d2be28b4d (patch)
tree82c3c37f534d2d27694ec1fea0af916d498bb99c /drivers/spi
parent0f4ad8d59f33b24dd86739f3be23e6af1a86f5a9 (diff)
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.c15
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);