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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 commits8b797490b4
("spi: gpio: Make sure spi_master_put() is called in every error path") and79567c1a32
("spi: gpio: Use devm_spi_register_master()"), which sought to plug leaks introduced by9b00bc7b90
("spi: spi-gpio: Rewrite to use GPIO descriptors") but missed this remaining leak. The situation was later aggravated by commitd3b0ffa1d7
("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:9b00bc7b90
("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+:5e844cc37a
: spi: Introduce device-managed SPI controller allocation Cc: <stable@vger.kernel.org> # v5.1-:8b797490b4
: spi: gpio: Make sure spi_master_put() is called in every error path Cc: <stable@vger.kernel.org> # v5.1-:45beec3519
: spi: bitbang: Introduce spi_bitbang_init() Cc: <stable@vger.kernel.org> # v5.1-:79567c1a32
: spi: gpio: Use devm_spi_register_master() Cc: <stable@vger.kernel.org> # v5.4-:d3b0ffa1d7
: 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>
This commit is contained in:
parent
0f4ad8d59f
commit
7174dc655e
@ -350,11 +350,6 @@ static int spi_gpio_probe_pdata(struct platform_device *pdev,
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return 0;
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}
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static void spi_gpio_put(void *data)
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{
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spi_master_put(data);
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}
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static int spi_gpio_probe(struct platform_device *pdev)
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{
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int status;
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@ -363,16 +358,10 @@ static int spi_gpio_probe(struct platform_device *pdev)
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struct device *dev = &pdev->dev;
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struct spi_bitbang *bb;
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master = spi_alloc_master(dev, sizeof(*spi_gpio));
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master = devm_spi_alloc_master(dev, sizeof(*spi_gpio));
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if (!master)
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return -ENOMEM;
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status = devm_add_action_or_reset(&pdev->dev, spi_gpio_put, master);
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if (status) {
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spi_master_put(master);
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return status;
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}
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if (pdev->dev.of_node)
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status = spi_gpio_probe_dt(pdev, master);
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else
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@ -432,7 +421,7 @@ static int spi_gpio_probe(struct platform_device *pdev)
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if (status)
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return status;
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return devm_spi_register_master(&pdev->dev, spi_master_get(master));
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return devm_spi_register_master(&pdev->dev, master);
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}
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MODULE_ALIAS("platform:" DRIVER_NAME);
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