linux-kernel - [PATCH v2] PM: Fix dev_pm_put_subsys_data() to not call kfree() while holding device power lock

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Date:	Mon, 6 May 2013 19:04:53 +0000
From:	Shuah Khan <shuah.kh@...sung.com>
To:	"len.brown@...el.com" <len.brown@...el.com>,
	"rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>,
	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
CC:	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"shuahkhan@...il.com" <shuahkhan@...il.com>,
	Shuah Khan <shuah.kh@...sung.com>
Subject: [PATCH v2] PM: Fix dev_pm_put_subsys_data() to not call kfree()
 while holding device power lock

dev_pm_put_subsys_data() calls kfree() while holding device power lock, when
the reference count is 0. Fix it to call kfree() after releasing the lock.

Signed-off-by: Shuah Khan <shuah.kh@...sung.com>
Reviewed-by: Pavel Machek <pavel@....cz>
Reviewed-by: Rafael Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/base/power/common.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c
index 39c3252..e5b99f7 100644
--- a/drivers/base/power/common.c
+++ b/drivers/base/power/common.c
@@ -61,24 +61,26 @@ EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data);
 int dev_pm_put_subsys_data(struct device *dev)
 {
 	struct pm_subsys_data *psd;
-	int ret = 0;
+	int ret = 1;
 
 	spin_lock_irq(&dev->power.lock);
 
 	psd = dev_to_psd(dev);
 	if (!psd) {
-		ret = -EINVAL;
 		goto out;
 	}
 
 	if (--psd->refcount == 0) {
 		dev->power.subsys_data = NULL;
-		kfree(psd);
 		ret = 1;
+	} else {
+		psd = NULL;
+		ret = 0;
 	}
 
  out:
 	spin_unlock_irq(&dev->power.lock);
+	kfree(psd);
 
 	return ret;
 }
-- 
1.7.10.4