From: Lukas Wunner <lukas@wunner.de> commit 7174dc655ef0578877b0b4598e69619d2be28b4d upstream. 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/86eaed27431c3d709e3748eb76ceecbfc790dd37.160728688... Signed-off-by: Mark Brown <broonie@kernel.org> [lukas: backport to v4.19.192] Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/spi/spi-gpio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c index 19687da237740..9defc0618e55b 100644 --- a/drivers/spi/spi-gpio.c +++ b/drivers/spi/spi-gpio.c @@ -387,7 +387,7 @@ static int spi_gpio_probe(struct platform_device *pdev) return -ENODEV; #endif - master = spi_alloc_master(&pdev->dev, sizeof(*spi_gpio)); + master = devm_spi_alloc_master(&pdev->dev, sizeof(*spi_gpio)); if (!master) return -ENOMEM; -- 2.25.1