extcon: Fix missing locking when [un]registering notifiers

PATCH New Hans de Goede 2 participants 2 messages Mar 21, 2015 – Mar 23, 2015 External connector subsystem (extcon)

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Hans de Goede

author

2015-03-21 16:26 UTC #0 lore raw

PATCH 1/1 extcon: Fix missing locking when [un]registering notifiers

Since extcon-class.c is using raw_notifiers it must protect the notifier list itself when [un]registering notifiers to avoid the list changing while extcon_update_state is walking the list (through raw_notifier_call_chain).

Signed-off-by Hans de Goede <[email protected]>

---
 drivers/extcon/extcon-class.c | 35 +++++++++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 4 deletions(-)

drivers/extcon/extcon-class.c +31 -4

index 8319f25..b079c41 100644
@@ -444,6 +444,9 @@ int extcon_register_interest(struct extcon_specific_cable_nb *obj,
 			     const char *extcon_name, const char *cable_name,
 			     struct notifier_block *nb)
 {
+	unsigned long flags;
+	int ret;
+
 	if (!obj || !cable_name || !nb)
 		return -EINVAL;

@@ -461,8 +464,11 @@ int extcon_register_interest(struct extcon_specific_cable_nb *obj,
 
 		obj->internal_nb.notifier_call = _call_per_cable;
 
-		return raw_notifier_chain_register(&obj->edev->nh,
+		spin_lock_irqsave(&obj->edev->lock, flags);
+		ret = raw_notifier_chain_register(&obj->edev->nh,
 						  &obj->internal_nb);
+		spin_unlock_irqrestore(&obj->edev->lock, flags);
+		return ret;
 	} else {
 		struct class_dev_iter iter;
 		struct extcon_dev *extd;

@@ -495,10 +501,17 @@ EXPORT_SYMBOL_GPL(extcon_register_interest);
  */
 int extcon_unregister_interest(struct extcon_specific_cable_nb *obj)
 {
+	unsigned long flags;
+	int ret;
+
 	if (!obj)
 		return -EINVAL;
 
-	return raw_notifier_chain_unregister(&obj->edev->nh, &obj->internal_nb);
+	spin_lock_irqsave(&obj->edev->lock, flags);
+	ret = raw_notifier_chain_unregister(&obj->edev->nh, &obj->internal_nb);
+	spin_unlock_irqrestore(&obj->edev->lock, flags);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(extcon_unregister_interest);

@@ -515,7 +528,14 @@ EXPORT_SYMBOL_GPL(extcon_unregister_interest);
 int extcon_register_notifier(struct extcon_dev *edev,
 			struct notifier_block *nb)
 {
-	return raw_notifier_chain_register(&edev->nh, nb);
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&edev->lock, flags);
+	ret = raw_notifier_chain_register(&edev->nh, nb);
+	spin_unlock_irqrestore(&edev->lock, flags);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(extcon_register_notifier);

@@ -527,7 +547,14 @@ EXPORT_SYMBOL_GPL(extcon_register_notifier);
 int extcon_unregister_notifier(struct extcon_dev *edev,
 			struct notifier_block *nb)
 {
-	return raw_notifier_chain_unregister(&edev->nh, nb);
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&edev->lock, flags);
+	ret = raw_notifier_chain_unregister(&edev->nh, nb);
+	spin_unlock_irqrestore(&edev->lock, flags);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(extcon_unregister_notifier);

Signature · 1 line

2.3.3

Chanwoo Choi

maintainer

2015-03-23 03:00 UTC #1 lore raw

PATCH 1/1 extcon: Fix missing locking when [un]registering notifiers

Hi Hans,

Looks good to me of this patch.

But,
I have some comment. You have to send extcon patch to linux-kernel at vger.kerne.org mailing list but you missed it. Also if you fixes extcon driver, you should develop them on extcon git repository because extcon-class.c was renamed to extcon.c. I added the extcon git repository and branch name.
- git repo : http://git.kernel.org/cgit/linux/kernel/git/chanwoo/extcon.git/
- branch : extcon-next

After I modified this patch without apply conflict personally, I applied it on extcon-next branch.

Thanks,
Chanwoo Choi

Quoted 88 lines · Hans de Goede

Signed-off-by Hans de Goede <[email protected]>

---
 drivers/extcon/extcon-class.c | 35 +++++++++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 4 deletions(-)

drivers/extcon/extcon-class.c +31 -4

index 8319f25..b079c41 100644
@@ -444,6 +444,9 @@ int extcon_register_interest(struct extcon_specific_cable_nb *obj,
 			     const char *extcon_name, const char *cable_name,
 			     struct notifier_block *nb)
 {
+	unsigned long flags;
+	int ret;
+
 	if (!obj || !cable_name || !nb)
 		return -EINVAL;

@@ -461,8 +464,11 @@ int extcon_register_interest(struct extcon_specific_cable_nb *obj,
 
 		obj->internal_nb.notifier_call = _call_per_cable;
 
-		return raw_notifier_chain_register(&obj->edev->nh,
+		spin_lock_irqsave(&obj->edev->lock, flags);
+		ret = raw_notifier_chain_register(&obj->edev->nh,
 						  &obj->internal_nb);
+		spin_unlock_irqrestore(&obj->edev->lock, flags);
+		return ret;
 	} else {
 		struct class_dev_iter iter;
 		struct extcon_dev *extd;

@@ -495,10 +501,17 @@ EXPORT_SYMBOL_GPL(extcon_register_interest);
  */
 int extcon_unregister_interest(struct extcon_specific_cable_nb *obj)
 {
+	unsigned long flags;
+	int ret;
+
 	if (!obj)
 		return -EINVAL;
 
-	return raw_notifier_chain_unregister(&obj->edev->nh, &obj->internal_nb);
+	spin_lock_irqsave(&obj->edev->lock, flags);
+	ret = raw_notifier_chain_unregister(&obj->edev->nh, &obj->internal_nb);
+	spin_unlock_irqrestore(&obj->edev->lock, flags);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(extcon_unregister_interest);

@@ -515,7 +528,14 @@ EXPORT_SYMBOL_GPL(extcon_unregister_interest);
 int extcon_register_notifier(struct extcon_dev *edev,
 			struct notifier_block *nb)
 {
-	return raw_notifier_chain_register(&edev->nh, nb);
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&edev->lock, flags);
+	ret = raw_notifier_chain_register(&edev->nh, nb);
+	spin_unlock_irqrestore(&edev->lock, flags);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(extcon_register_notifier);

@@ -527,7 +547,14 @@ EXPORT_SYMBOL_GPL(extcon_register_notifier);
 int extcon_unregister_notifier(struct extcon_dev *edev,
 			struct notifier_block *nb)
 {
-	return raw_notifier_chain_unregister(&edev->nh, nb);
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&edev->lock, flags);
+	ret = raw_notifier_chain_unregister(&edev->nh, nb);
+	spin_unlock_irqrestore(&edev->lock, flags);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(extcon_unregister_notifier);