| From | Luis Henriques <> | Subject | [PATCH 3.16.y-ckt 025/104] spi: Fix documentation of spi_alloc_master() | Date | Mon, 26 Oct 2015 13:42:07 +0000 |
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3.16.7-ckt19 -stable review patch. If anyone has any objections, please let me know.
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From: Guenter Roeck <linux@roeck-us.net>
commit a394d635193b641f2c86ead5ada5b115d57c51f8 upstream.
Actually, spi_master_put() after spi_alloc_master() must _not_ be followed by kfree(). The memory is already freed with the call to spi_master_put() through spi_master_class, which registers a release function. Calling both spi_master_put() and kfree() results in often nasty (and delayed) crashes elsewhere in the kernel, often in the networking stack.
This reverts commit eb4af0f5349235df2e4a5057a72fc8962d00308a.
Link to patch and concerns: https://lkml.org/lkml/2012/9/3/269 or http://lkml.iu.edu/hypermail/linux/kernel/1209.0/00790.html
Alexey Klimov: This revert becomes valid after 94c69f765f1b4a658d96905ec59928e3e3e07e6a when spi-imx.c has been fixed and there is no need to call kfree() so comment for spi_alloc_master() should be fixed.
Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/spi/spi.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 3950e4495093..8f2c442eb1e1 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1458,8 +1458,7 @@ static struct class spi_master_class = { * * The caller is responsible for assigning the bus number and initializing * the master's methods before calling spi_register_master(); and (after errors - * adding the device) calling spi_master_put() and kfree() to prevent a memory - * leak. + * adding the device) calling spi_master_put() to prevent a memory leak. */ struct spi_master *spi_alloc_master(struct device *dev, unsigned size) {
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