From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Guenter Roeck <linux@roeck-us.net>
Cc: spi-devel-general@lists.sourceforge.net,
linux-kernel@vger.kernel.org,
Grant Likely <grant.likely@secretlab.ca>,
Mark Brown <broonie@opensource.wolfsonmicro.com>,
kernel@pengutronix.de
Subject: Re: [PATCH] Revert "spi/doc: spi_master_put must be followed up by kfree"
Date: Tue, 4 Sep 2012 09:25:23 +0200 [thread overview]
Message-ID: <20120904072523.GB28643@pengutronix.de> (raw)
In-Reply-To: <1346703986-7849-1-git-send-email-linux@roeck-us.net>
On Mon, Sep 03, 2012 at 01:26:26PM -0700, Guenter Roeck wrote:
> 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.
>
> Cc: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
I didn't check the callback, but I introduced
eb4af0f5349235df2e4a5057a72fc8962d00308a because I saw the kfree in
drivers/spi/spi-imx.c. So I guess this needs fixing, too?!
Best regards
Uwe
> ---
> 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 2d9b5bb..6470750 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -1082,8 +1082,7 @@ 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)
> {
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
next prev parent reply other threads:[~2012-09-04 7:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-03 20:26 [PATCH] Revert "spi/doc: spi_master_put must be followed up by kfree" Guenter Roeck
2012-09-04 7:25 ` Uwe Kleine-König [this message]
2012-09-04 11:57 ` Guenter Roeck
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