Re: [PATCH v2] PCI: Fix crash during pci_dev hot-unplug on pseries KVM guest

[Lizhi Hou]

On 7/26/24 10:52, Rob Herring wrote:
> On Thu, Jul 25, 2024 at 6:06 PM Lizhi Hou <lizhi.hou@xxxxxxx> wrote:
> > Hi Amit,
> >
> >
> > I try to follow the option which add a OF flag. If Rob is ok with this,
> > I would suggest to use it instead of V1 patch
> >
> > diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
> > index dda6092e6d3a..a401ed0463d9 100644
> > --- a/drivers/of/dynamic.c
> > +++ b/drivers/of/dynamic.c
> > @@ -382,6 +382,11 @@ void of_node_release(struct kobject *kobj)
> >                                  __func__, node);
> >           }
> >
> > +       if (of_node_check_flag(node, OF_CREATED_WITH_CSET)) {
> > +               of_changeset_revert(node->data);
> > +               of_changeset_destroy(node->data);
> > +       }
> What happens if multiple nodes are created in the changeset?
Ok. multiple nodes will not work.
> > +
> >           if (node->child)
> >                   pr_err("ERROR: %s() unexpected children for %pOF/%s\n",
> >                           __func__, node->parent, node->full_name);
> > @@ -507,6 +512,7 @@ struct device_node *of_changeset_create_node(struct
> > of_changeset *ocs,
> >           np = __of_node_dup(NULL, full_name);
> >           if (!np)
> >                   return NULL;
> > +       of_node_set_flag(np, OF_CREATED_WITH_CSET);
> This should be set where the data ptr is set.

Ok. It sounds the fix could be simplified to 3 lines change.


diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 51e3dd0ea5ab..0b3ba1e1b18c 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -613,7 +613,7 @@ void of_pci_remove_node(struct pci_dev *pdev)
        struct device_node *np;

        np = pci_device_to_OF_node(pdev);
-       if (!np || !of_node_check_flag(np, OF_DYNAMIC))
+       if (!np || !of_node_check_flag(np, OF_CREATED_WITH_CSET))
                return;
        pdev->dev.of_node = NULL;

@@ -672,6 +672,7 @@ void of_pci_make_dev_node(struct pci_dev *pdev)
        if (ret)
                goto out_free_node;

+       of_node_set_flag(np, OF_CREATED_WITH_CSET);
        np->data = cset;
        pdev->dev.of_node = np;
        kfree(name);
diff --git a/include/linux/of.h b/include/linux/of.h
index a0bedd038a05..a46317f6626e 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -153,6 +153,7 @@ extern struct device_node *of_stdout;
 #define OF_POPULATED_BUS       4 /* platform bus created for children */
 #define OF_OVERLAY             5 /* allocated for an overlay */
 #define OF_OVERLAY_FREE_CSET   6 /* in overlay cset being freed */
+#define OF_CREATED_WITH_CSET    7 /* created by of_changeset_create_node */

 #define OF_BAD_ADDR    ((u64)-1)


Lizhi

> Rob