From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guenter Roeck , Alexey Klimov , Mark Brown Subject: [PATCH 4.2 081/258] spi: Fix documentation of spi_alloc_master() Date: Sat, 17 Oct 2015 18:56:34 -0700 Message-Id: <20151018014734.070428002@linuxfoundation.org> In-Reply-To: <20151018014729.976101177@linuxfoundation.org> References: <20151018014729.976101177@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Guenter Roeck 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 Signed-off-by: Alexey Klimov Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman --- drivers/spi/spi.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1437,8 +1437,7 @@ 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) {