On Wed, Nov 21, 2012 at 03:06:29PM +0100, Michael Grzeschik wrote:
From: Marc Kleine-Budde <mkl@pengutronix.de>
This fixes a potential race condition where the ci13xxx_imx glue code
could be fast enough to call one of the usbmisc_ops before he got a
valid value on the static usbmisc pointer. To fix that we first set
usbmisc, then call usbmisc_set_ops().
usbmisc is subsys_initcall, and cil13xxx_imx is module_init. Any
potential situation that the ci13xxx_imx's probe is ran before the
usbmisc's probe is completed? Besides, there is usbmisc_ops value
check at the beginning of cil13xxx_imx's probe.
quoted hunk
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Michael Grzeschik <redacted>
---
Changes since v1:
* split previous patch into two seperate.
drivers/usb/chipidea/usbmisc_imx.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/chipidea/usbmisc_imx.c b/drivers/usb/chipidea/usbmisc_imx.c
index 552c63f..9145e04 100644
--- a/drivers/usb/chipidea/usbmisc_imx.c
+++ b/drivers/usb/chipidea/usbmisc_imx.c
@@ -116,14 +116,14 @@ static int __devinit usbmisc_imx_probe(struct platform_device *pdev)
return ret;
}
+ usbmisc = data;
ret = usbmisc_set_ops(&imx6q_usbmisc_ops);
if (ret) {
+ usbmisc = NULL;
clk_disable_unprepare(data->clk);
return ret;
}
- usbmisc = data;
-
return 0;
}
--
1.7.10.4
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Best Regards,
Peter Chen
On Fri, Nov 23, 2012 at 01:36:36PM +0800, Peter Chen wrote:
On Wed, Nov 21, 2012 at 03:06:29PM +0100, Michael Grzeschik wrote:
quoted
From: Marc Kleine-Budde <mkl@pengutronix.de>
This fixes a potential race condition where the ci13xxx_imx glue code
could be fast enough to call one of the usbmisc_ops before he got a
valid value on the static usbmisc pointer. To fix that we first set
usbmisc, then call usbmisc_set_ops().
usbmisc is subsys_initcall, and cil13xxx_imx is module_init. Any
potential situation that the ci13xxx_imx's probe is ran before the
usbmisc's probe is completed?
Not having looked at the code you are referring to at all I just want
to say that: drivers can be modules (don't know if that's true for
chipidea) and sooner or later we'll probably get devicetree overlays, so
the devicetree nodes might just appear during runtime. Depending on
initcall order is generally not a good idea.
Sascha
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Industrial Linux Solutions | http://www.pengutronix.de/ |
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On 11/23/2012 06:36 AM, Peter Chen wrote:
On Wed, Nov 21, 2012 at 03:06:29PM +0100, Michael Grzeschik wrote:
quoted
From: Marc Kleine-Budde <mkl@pengutronix.de>
This fixes a potential race condition where the ci13xxx_imx glue code
could be fast enough to call one of the usbmisc_ops before he got a
valid value on the static usbmisc pointer. To fix that we first set
usbmisc, then call usbmisc_set_ops().
usbmisc is subsys_initcall, and cil13xxx_imx is module_init. Any
potential situation that the ci13xxx_imx's probe is ran before the
usbmisc's probe is completed? Besides, there is usbmisc_ops value
check at the beginning of cil13xxx_imx's probe.
It's bad practice to rely your code on some external ordering mechanism,
even more if the correct solution is so simple. And as Sascha pointed
out everything might be build as modules and loaded individually.
Marc
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Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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