| Message ID | 334a9052264630b9157fa9bfc3d4efe945054c34.1439288881.git.viresh.kumar@linaro.org (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On Tue, Aug 11, 2015 at 04:04:34PM +0530, Viresh Kumar wrote: > _of_init_opp_table_v2() isn't freeing up resources on some errors and > the error values returned are also not correct always. > > This fixes following problems: > - Return -ENOENT, if no entries are found in the table. > - Use IS_ERR() to properly check return value of _find_device_opp(). > - Return error value with PTR_ERR() in above case. > - Free table if _find_device_opp() fails. > > Fixes: 274659029c9d ("PM / OPP: Add support to parse operating-points-v2" bindings") > Reported-by: Dan Carpenter <dan.carpenter@oracle.com> > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > drivers/base/power/opp.c | 29 +++++++++++++++-------------- > 1 file changed, 15 insertions(+), 14 deletions(-) > > diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c > index 204c6c945168..bcbd92c3b717 100644 > --- a/drivers/base/power/opp.c > +++ b/drivers/base/power/opp.c > @@ -1323,28 +1323,29 @@ static int _of_init_opp_table_v2(struct device *dev, > if (ret) { > dev_err(dev, "%s: Failed to add OPP, %d\n", __func__, > ret); > - break; > + goto free_table; > } > } > > /* There should be one of more OPP defined */ > - if (WARN_ON(!count)) > + if (WARN_ON(!count)) { > + ret = -ENOENT; > goto put_opp_np; > + } This is weird to me, because we are going backwards. What happens if we goto free_table without adding anything? I suspect it's fine, but if it's a bug then this code still has problems. What about if we only increment count when _opp_add_static_v2() succeeds, and change it back to the original where we break, check count, then check ret. That way we don't need to know the details of free_table to see that the code is correct. regards, dan carpenter -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 11-08-15, 17:43, Dan Carpenter wrote: > > @@ -1323,28 +1323,29 @@ static int _of_init_opp_table_v2(struct device *dev, > > if (ret) { > > dev_err(dev, "%s: Failed to add OPP, %d\n", __func__, > > ret); > > - break; > > + goto free_table; > > } > > } > > > > /* There should be one of more OPP defined */ > > - if (WARN_ON(!count)) > > + if (WARN_ON(!count)) { > > + ret = -ENOENT; > > goto put_opp_np; > > + } The purpose of 'count' here is to see if the dtb contained any OPP nodes or not. i.e. if we ever entered the body of for_each_available_child_of_node() or not.. Its different than, "if we were able to add any OPPs"; > This is weird to me, because we are going backwards. What happens if > we goto free_table without adding anything? It will WARN() today. > I suspect it's fine, but if > it's a bug then this code still has problems. I don't think we have a bug here, we never added anything and so don't need to free it. > What about if we only increment count when _opp_add_static_v2() > succeeds That's not what we want.
On Tue, Aug 11, 2015 at 08:29:38PM +0530, Viresh Kumar wrote: > > This is weird to me, because we are going backwards. What happens if > > we goto free_table without adding anything? > > It will WARN() today. Then the current code is buggy. > > > I suspect it's fine, but if > > it's a bug then this code still has problems. > > I don't think we have a bug here, we never added anything and so don't > need to free it. > > > What about if we only increment count when _opp_add_static_v2() > > succeeds > > That's not what we want. If the first call to _opp_add_static_v2() fails we call of_free_opp_table() and you say that triggers a WARN(). regards, dan carpenter -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 11-08-15, 20:11, Dan Carpenter wrote: > On Tue, Aug 11, 2015 at 08:29:38PM +0530, Viresh Kumar wrote: > > > This is weird to me, because we are going backwards. What happens if > > > we goto free_table without adding anything? > > > > It will WARN() today. > > Then the current code is buggy. Urg, it wouldn't WARN in this case. Sorry, didn't read it correctly earlier. > > > I suspect it's fine, but if > > > it's a bug then this code still has problems. > > > > I don't think we have a bug here, we never added anything and so don't > > need to free it. > > > > > What about if we only increment count when _opp_add_static_v2() > > > succeeds > > > > That's not what we want. > > If the first call to _opp_add_static_v2() fails we call > of_free_opp_table() and you say that triggers a WARN(). No it doesn't. So, coming back to the point you made about freeing table on !count, because there were no nodes present in the DT opp table, we have never tried to add any OPPs. And so there is no need to call of_free_opp_table() in that case. Do you still think the current code is wrong ?
On Wed, Aug 12, 2015 at 12:13:09PM +0530, Viresh Kumar wrote: > > If the first call to _opp_add_static_v2() fails we call > > of_free_opp_table() and you say that triggers a WARN(). > > No it doesn't. > > So, coming back to the point you made about freeing table on !count, > because there were no nodes present in the DT opp table, we have never > tried to add any OPPs. And so there is no need to call > of_free_opp_table() in that case. > > Do you still think the current code is wrong ? If it doesn't WARN() then it's not buggy, but it's still ugly. We should not call of_free_opp_table() because we *tried* to add an OPP, we should only call it if we *succeeded*. The way the code is written and from your emails I was afraid that if you tried to call _opp_add_static_v2() and it fails then it leaves artifacts lying around that need to be cleaned up by the caller. This would be the ugliest scenario. But I looked at _opp_add_static_v2() and looks fine. It cleans up properly on failure. We only need to clean up if it succeeds. regards, dan carpenter -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c index 204c6c945168..bcbd92c3b717 100644 --- a/drivers/base/power/opp.c +++ b/drivers/base/power/opp.c @@ -1323,28 +1323,29 @@ static int _of_init_opp_table_v2(struct device *dev, if (ret) { dev_err(dev, "%s: Failed to add OPP, %d\n", __func__, ret); - break; + goto free_table; } } /* There should be one of more OPP defined */ - if (WARN_ON(!count)) + if (WARN_ON(!count)) { + ret = -ENOENT; goto put_opp_np; + } - if (!ret) { - if (!dev_opp) { - dev_opp = _find_device_opp(dev); - if (WARN_ON(!dev_opp)) - goto put_opp_np; - } - - dev_opp->np = opp_np; - dev_opp->shared_opp = of_property_read_bool(opp_np, - "opp-shared"); - } else { - of_free_opp_table(dev); + dev_opp = _find_device_opp(dev); + if (WARN_ON(IS_ERR(dev_opp))) { + ret = PTR_ERR(dev_opp); + goto free_table; } + dev_opp->np = opp_np; + dev_opp->shared_opp = of_property_read_bool(opp_np, "opp-shared"); + + goto put_opp_np; + +free_table: + of_free_opp_table(dev); put_opp_np: of_node_put(opp_np);
_of_init_opp_table_v2() isn't freeing up resources on some errors and the error values returned are also not correct always. This fixes following problems: - Return -ENOENT, if no entries are found in the table. - Use IS_ERR() to properly check return value of _find_device_opp(). - Return error value with PTR_ERR() in above case. - Free table if _find_device_opp() fails. Fixes: 274659029c9d ("PM / OPP: Add support to parse operating-points-v2" bindings") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- drivers/base/power/opp.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-)