On Mon, Nov 16, 2015 at 12:33:14PM +0100, Julia Lawall wrote: > for_each_available_child_of_node performs an of_node_get on each iteration, > so a return from the middle of the loop requires an of_node_put. > > A simplified version of the semantic patch that finds this problem is as > follows (http://coccinelle.lip6.fr): > > // <smpl> > @@ > expression root,e; > local idexpression child; > @@ > > for_each_available_child_of_node(root, child) { > ... when != of_node_put(child) > when != e = child > ( > return child; > | > * return ...; > ) > ... > } > // </smpl> > > Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxx> > > --- For this patch: Acked-by: Brian Norris <computersforpeace@xxxxxxxxx> > drivers/phy/phy-brcmstb-sata.c | 17 ++++++++++++----- > 1 file changed, 12 insertions(+), 5 deletions(-) [snip patch, which fixes of_node_put() handling for for_each_available_child_of_node() loop, which creates PHY devices with devm_phy_create()] This reminds me of a potential problem I'm looking at in other subsystems: from code reading (I haven't seen any issues in practice, probably because I don't use OF_DYNAMIC) it looks like device-creating infrastructure like the PHY subsystem should be acquiring a reference to the device_node when they stash it away. But drivers/phy/phy-core.c does not do this, AFAICT. See phy_create(), which does phy->dev.of_node = node ?: dev->of_node; and later might reuse this of_node pointer, even though it never called of_node_get() on this node. Potential patch to fix this (not tested). Signed-off-by: Brian Norris <computersforpeace@xxxxxxxxx> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c index fc48fac003a6..8df29caeeef9 100644 --- a/drivers/phy/phy-core.c +++ b/drivers/phy/phy-core.c @@ -697,6 +697,7 @@ struct phy *phy_create(struct device *dev, struct device_node *node, phy->dev.class = phy_class; phy->dev.parent = dev; phy->dev.of_node = node ?: dev->of_node; + of_node_get(phy->dev.of_node); phy->id = id; phy->ops = ops; @@ -726,6 +727,7 @@ struct phy *phy_create(struct device *dev, struct device_node *node, return phy; put_dev: + of_node_put(phy->dev.of_node); put_device(&phy->dev); /* calls phy_release() which frees resources */ return ERR_PTR(ret); @@ -775,6 +777,7 @@ EXPORT_SYMBOL_GPL(devm_phy_create); */ void phy_destroy(struct phy *phy) { + of_node_put(phy->dev.of_node); pm_runtime_disable(&phy->dev); device_unregister(&phy->dev); } -- 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
