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Subject[PATCH v2 2/6] of: dynamic: Refactor action prints to not use "%pOF" inside devtree_lock
While originally it was fine to format strings using "%pOF" while
holding devtree_lock, this now causes a deadlock. Lockdep reports:

of_get_parent from of_fwnode_get_parent+0x18/0x24
^^^^^^^^^^^^^
of_fwnode_get_parent from fwnode_count_parents+0xc/0x28
fwnode_count_parents from fwnode_full_name_string+0x18/0xac
fwnode_full_name_string from device_node_string+0x1a0/0x404
device_node_string from pointer+0x3c0/0x534
pointer from vsnprintf+0x248/0x36c
vsnprintf from vprintk_store+0x130/0x3b4

Fix this by moving the printing in __of_changeset_entry_apply() outside
the lock. As the only difference in the the multiple prints is the
action name, use the existing "action_names" to refactor the prints into
a single print.

Fixes: a92eb7621b9fb2c2 ("lib/vsprintf: Make use of fwnode API to obtain node names and separators")
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rob Herring <robh@kernel.org>
---
v5 (v2 in this series):
- Move majority of refactoring to separate patch and minimize the fix
to just moving the print out of the locked section.
v4:
- Add missing 'static' reported by 0-day
v3:
- Re-implement Geert's fix to move the prints rather than move the
spinlock

v1 and v2 from Geert simply moved the devtree_lock into each case
statement:

https://lore.kernel.org/all/c593d8389352c574b5be69d4ca4810da13326a50.1690533838.git.geert+renesas@glider.be/
---
drivers/of/dynamic.c | 27 +++++----------------------
1 file changed, 5 insertions(+), 22 deletions(-)

diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index e311d406b170..2f0eb0053773 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -63,15 +63,13 @@ int of_reconfig_notifier_unregister(struct notifier_block *nb)
}
EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);

-#ifdef DEBUG
-const char *action_names[] = {
+static const char *action_names[] = {
[OF_RECONFIG_ATTACH_NODE] = "ATTACH_NODE",
[OF_RECONFIG_DETACH_NODE] = "DETACH_NODE",
[OF_RECONFIG_ADD_PROPERTY] = "ADD_PROPERTY",
[OF_RECONFIG_REMOVE_PROPERTY] = "REMOVE_PROPERTY",
[OF_RECONFIG_UPDATE_PROPERTY] = "UPDATE_PROPERTY",
};
-#endif

int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
{
@@ -620,21 +618,9 @@ static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
}

ret = __of_add_property(ce->np, ce->prop);
- if (ret) {
- pr_err("changeset: add_property failed @%pOF/%s\n",
- ce->np,
- ce->prop->name);
- break;
- }
break;
case OF_RECONFIG_REMOVE_PROPERTY:
ret = __of_remove_property(ce->np, ce->prop);
- if (ret) {
- pr_err("changeset: remove_property failed @%pOF/%s\n",
- ce->np,
- ce->prop->name);
- break;
- }
break;

case OF_RECONFIG_UPDATE_PROPERTY:
@@ -648,20 +634,17 @@ static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
}

ret = __of_update_property(ce->np, ce->prop, &old_prop);
- if (ret) {
- pr_err("changeset: update_property failed @%pOF/%s\n",
- ce->np,
- ce->prop->name);
- break;
- }
break;
default:
ret = -EINVAL;
}
raw_spin_unlock_irqrestore(&devtree_lock, flags);

- if (ret)
+ if (ret) {
+ pr_err("changeset: apply failed: cset<%p> %-15s %pOF:%s\n",
+ ce, action_names[ce->action], ce->np, ce->prop->name);
return ret;
+ }

switch (ce->action) {
case OF_RECONFIG_ATTACH_NODE:
--
2.40.1

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