Messages in this thread | | | Subject | Re: [PATCH] spi: bcm2835: Fix buffer overflow with CS able to go beyond limit. | From | Florian Fainelli <> | Date | Thu, 22 Apr 2021 09:50:47 -0700 |
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On 4/20/2021 1:34 AM, Joe Burmeister wrote: > It was previoulsy possible to have a device tree with more chips than > the driver supports and go off the end of CS arrays.
Do you mind walking me through the code how that could have happened? We have spi_register_controller() call of_spi_get_gpio_numbers() which has the following:
ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
such that what the controller has is the maximum between the number of 'cs-gpios' properties parsed and what was already populated in ctrl->num_chipselect during bcm2835_spi_probe(), which for this driver is BCM2835_SPI_NUM_CS (3).
> > This patches inforces CS limit but sets that limit to the max of the > default limit and what is in the device tree when driver is loaded. > > Signed-off-by: Joe Burmeister <joe.burmeister@devtank.co.uk>
You have changed many more things that just enforcing a limit on BCM2835_SPI_NUM_CS you have now made all chip-select related data structuresd dynamically allocated and you have changed a number of prints to use the shorthand "dev" instead of &pdev->dev. -- Florian
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