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Message-Id: <20230728231950.1619073-1-robh@kernel.org>
Date: Fri, 28 Jul 2023 17:19:50 -0600
From: Rob Herring <robh@...nel.org>
To: Frank Rowand <frowand.list@...il.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
Petr Mladek <pmladek@...e.com>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc: Geert Uytterhoeven <geert+renesas@...der.be>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v3] 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
To fix this, move the printing in __of_changeset_entry_apply() outside the
lock. As there's already similar printing of the same changeset actions,
refactor all of them to use a common action print function. This has the
side benefit of getting rid of some ifdefs.
Fixes: a92eb7621b9fb2c2 ("lib/vsprintf: Make use of fwnode API to obtain node names and separators")
Reported-by: Geert Uytterhoeven <geert+renesas@...der.be>
Signed-off-by: Rob Herring <robh@...nel.org>
---
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 | 79 ++++++++++----------------------------------
1 file changed, 17 insertions(+), 62 deletions(-)
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index e311d406b170..6edb084e928a 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -63,37 +63,30 @@ 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
+
+void of_changeset_action_print(unsigned long action, struct device_node *np, const char *prop_name)
+{
+ if (prop_name)
+ pr_cont("%-15s %pOF:%s\n", action_names[action], np, prop_name);
+ else
+ pr_cont("%-15s %pOF\n", action_names[action], np);
+}
int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
{
int rc;
-#ifdef DEBUG
struct of_reconfig_data *pr = p;
- switch (action) {
- case OF_RECONFIG_ATTACH_NODE:
- case OF_RECONFIG_DETACH_NODE:
- pr_debug("notify %-15s %pOF\n", action_names[action],
- pr->dn);
- break;
- case OF_RECONFIG_ADD_PROPERTY:
- case OF_RECONFIG_REMOVE_PROPERTY:
- case OF_RECONFIG_UPDATE_PROPERTY:
- pr_debug("notify %-15s %pOF:%s\n", action_names[action],
- pr->dn, pr->prop->name);
- break;
+ if (pr_debug("notify "))
+ of_changeset_action_print(action, pr->dn, pr->prop ? pr->prop->name : NULL);
- }
-#endif
rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
return notifier_to_errno(rc);
}
@@ -504,30 +497,6 @@ static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
kfree(ce);
}
-#ifdef DEBUG
-static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
-{
- switch (ce->action) {
- case OF_RECONFIG_ADD_PROPERTY:
- case OF_RECONFIG_REMOVE_PROPERTY:
- case OF_RECONFIG_UPDATE_PROPERTY:
- pr_debug("cset<%p> %-15s %pOF/%s\n", ce, action_names[ce->action],
- ce->np, ce->prop->name);
- break;
- case OF_RECONFIG_ATTACH_NODE:
- case OF_RECONFIG_DETACH_NODE:
- pr_debug("cset<%p> %-15s %pOF\n", ce, action_names[ce->action],
- ce->np);
- break;
- }
-}
-#else
-static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
-{
- /* empty */
-}
-#endif
-
static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
struct of_changeset_entry *rce)
{
@@ -599,7 +568,8 @@ static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
unsigned long flags;
int ret = 0;
- __of_changeset_entry_dump(ce);
+ if (pr_debug("changeset: applying: cset<%p> ", ce))
+ of_changeset_action_print(ce->action, ce->np, ce->prop ? ce->prop->name : NULL);
raw_spin_lock_irqsave(&devtree_lock, flags);
switch (ce->action) {
@@ -620,21 +590,9 @@ 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 +606,17 @@ 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> ", ce);
+ of_changeset_action_print(ce->action, ce->np, ce->prop ? ce->prop->name : NULL);
return ret;
+ }
switch (ce->action) {
case OF_RECONFIG_ATTACH_NODE:
--
2.40.1
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