On 15/07/17 09:42, Julia Lawall wrote: > Device node iterators perform an of_node_put on each iteration, so putting > an of_node_put before a continue results in a double put. > > The semantic match that finds this problem is as follows > (http://coccinelle.lip6.fr): > > // <smpl> > @@ > expression e1; > local idexpression child; > iterator name for_each_child_of_node; > @@ > > for_each_child_of_node(e1,child) { > ... when != of_node_get(child) > * of_node_put(child); > ... > * continue; > } > // </smpl> > > Furthermore, the call to thermal_of_cooling_device_register immediately > calls __thermal_cooling_device_register with the same arguments. The > latter function stores the device node argument, which is the second > argument of for_each_child_of_node, in the returned thermal_cooling_device > structure. This returned structure is then stored in the cdev field of > stc. Thus it seems that the second argument of for_each_child_of_node > escapes the scope of the for_each_child_of_node, so an explicit of_node_get > on success of thermal_of_cooling_device_register is also needed. > > Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxx> > > --- > drivers/thermal/tegra/soctherm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/thermal/tegra/soctherm.c b/drivers/thermal/tegra/soctherm.c > index 7d2db23..10f4fdd 100644 > --- a/drivers/thermal/tegra/soctherm.c > +++ b/drivers/thermal/tegra/soctherm.c > @@ -1014,7 +1014,6 @@ static void soctherm_init_hw_throt_cdev(struct platform_device *pdev) > tcd = thermal_of_cooling_device_register(np_stcc, > (char *)name, ts, > &throt_cooling_ops); > - of_node_put(np_stcc); > if (IS_ERR_OR_NULL(tcd)) { > dev_err(dev, > "throttle-cfg: %s: failed to register cooling device\n", > @@ -1022,6 +1021,7 @@ static void soctherm_init_hw_throt_cdev(struct platform_device *pdev) > continue; > } > > + of_node_get(np_stcc); > stc->cdev = tcd; > stc->init = true; > } Thanks for fixing this. However, I am wondering if it is better for the 'of_node_get' to be placed within the thermal_of_cooling_device_register() function as it seems a bit odd if the caller needs to know that this is being stored for later use. Also, taking a quick look, I see a couple other drivers calling thermal_of_cooling_device_register() and they are also not calling of_node_get on success. So it maybe easier to fix placing it in the thermal_of_cooling_device_register() function. Cheers Jon -- nvpublic -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
