[PATCH 3.12 023/107] ARM: mvebu: Fix kernel hang in mvebu_soc_id_init() when of_iomap failed

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Gregory CLEMENT <gregory.clement@free-electrons.com>

commit dc4910d9e93f8cc56b190dd8fc9e789135978216 upstream.

When pci_base is accessed whereas it has not been properly mapped by
of_iomap() the kernel hang. The check of this pointer made an improper
use of IS_ERR() instead of comparing to NULL. This patch fix this
issue.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reported-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Fixes: 930ab3d403ae (i2c: mv64xxx: Add I2C Transaction Generator support)
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/arm/mach-mvebu/mvebu-soc-id.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm/mach-mvebu/mvebu-soc-id.c
+++ b/arch/arm/mach-mvebu/mvebu-soc-id.c
@@ -88,7 +88,7 @@ static int __init mvebu_soc_id_init(void
 	}
 
 	pci_base = of_iomap(child, 0);
-	if (IS_ERR(pci_base)) {
+	if (pci_base == NULL) {
 		pr_err("cannot map registers\n");
 		ret = -ENOMEM;
 		goto res_ioremap;