[PATCH] mailbox: xgene-slimpro: Fix potential NULL pointer dereference

["Gustavo A. R. Silva" <gustavo@embeddedor.com>]

There is a potential execution path in which function
platform_get_resource() returns NULL. If this happens,
we will end up having a NULL pointer dereference.

Fix this by adding a sanity check in order to avoid a
NULL pointer dereference.

This code was detected with the help of Coccinelle.

Cc: stable@vger.kernel.org
Fixes: f700e84f417b ("mailbox: Add support for APM X-Gene platform mailbox driver")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/mailbox/mailbox-xgene-slimpro.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mailbox/mailbox-xgene-slimpro.c b/drivers/mailbox/mailbox-xgene-slimpro.c
index a704016..d2c02b7 100644
--- a/drivers/mailbox/mailbox-xgene-slimpro.c
+++ b/drivers/mailbox/mailbox-xgene-slimpro.c
@@ -195,6 +195,9 @@ static int slimpro_mbox_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, ctx);
 
 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!regs)
+		return -EINVAL;
+
 	mb_base = devm_ioremap(&pdev->dev, regs->start, resource_size(regs));
 	if (!mb_base)
 		return -ENOMEM;
-- 
2.7.4