Messages in this thread Patch in this message | | | Date | Fri, 26 Aug 2022 16:14:01 -0500 | From | Bjorn Helgaas <> | Subject | Re: [PATCH -next 1/3] PCI: fix double put_device() in error case in pci_create_root_bus() |
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[+cc Rob]
On Thu, Aug 25, 2022 at 08:27:51PM +0800, Yang Yingliang wrote: > If device_add() fails in pci_register_host_bridge(), the brigde device will > be put once, and it will be put again in error path of pci_create_root_bus(). > Move the put_device() from pci_create_root_bus() to pci_register_host_bridge() > to fix this problem. And use device_unregister() instead of del_device() and > put_device().
s/brigde/bridge/
> Fixes: 9885440b16b8 ("PCI: Fix pci_host_bridge struct device release/free handling")
If you're fixing a commit from somebody else, please always cc: the author because the author can help review the change.
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> > --- > drivers/pci/probe.c | 8 ++------ > 1 file changed, 2 insertions(+), 6 deletions(-) > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index c5286b027f00..e500eb9d6468 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -1027,7 +1027,7 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge) > > unregister: > put_device(&bridge->dev); > - device_del(&bridge->dev); > + device_unregister(&bridge->dev);
I don't understand this part. device_unregister() looks like this:
void device_unregister(struct device *dev) { device_del(dev); put_device(dev); }
So this calls put_device(&bridge->dev) twice, doesn't it?
The "unregister" label looks poorly named. We only get there if device_register() *failed*. We shouldn't need to unregister anything in that case.
> free: > kfree(bus); > @@ -3037,13 +3037,9 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus, > > error = pci_register_host_bridge(bridge); > if (error < 0) > - goto err_out; > + return NULL; > > return bridge->bus; > - > -err_out: > - put_device(&bridge->dev); > - return NULL;
This part looks right to me. The get_device() is in pci_register_host_bridge(), and if pci_register_host_bridge() returns failure, I think it should first do the corresponding put_device().
> } > EXPORT_SYMBOL_GPL(pci_create_root_bus); > > -- > 2.25.1 >
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