[PATCH] [RESEND] devres: Fix possible use after free

[Maxin B John <maxin.john@gmail.com>]

A freed pointer is passed as an argument to the function "devres_destroy()" in
"kernel/irq/devres.c" and "lib/devres.c". This patch fixes the possible use 
after free.

It's notabug at this time, but the code is dangerous.

Signed-off-by: Maxin B. John <maxin.john@gmail.com>
Reviewed-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Acked-by: Tejun Heo <tj@kernel.org>
---
diff --git a/kernel/irq/devres.c b/kernel/irq/devres.c
index 1ef4ffc..bd8e788 100644
--- a/kernel/irq/devres.c
+++ b/kernel/irq/devres.c
@@ -87,8 +87,8 @@ void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id)
 {
 	struct irq_devres match_data = { irq, dev_id };
 
-	free_irq(irq, dev_id);
 	WARN_ON(devres_destroy(dev, devm_irq_release, devm_irq_match,
 			       &match_data));
+	free_irq(irq, dev_id);
 }
 EXPORT_SYMBOL(devm_free_irq);
diff --git a/lib/devres.c b/lib/devres.c
index 6efddf5..7c0e953 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -79,9 +79,9 @@ EXPORT_SYMBOL(devm_ioremap_nocache);
  */
 void devm_iounmap(struct device *dev, void __iomem *addr)
 {
-	iounmap(addr);
 	WARN_ON(devres_destroy(dev, devm_ioremap_release, devm_ioremap_match,
 			       (void *)addr));
+	iounmap(addr);
 }
 EXPORT_SYMBOL(devm_iounmap);