[PATCH] nfc: fdp: fix NULL pointer dereference

From: Sudip Mukherjee
Date: Tue Dec 20 2016 - 16:09:18 EST


We are checking phy after dereferencing it. We can print the debug
information after checking it. If phy is NULL then we will get a good
stack trace to tell us that we are in this irq handler.

Signed-off-by: Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxxxxxxx>
---
drivers/nfc/fdp/i2c.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/nfc/fdp/i2c.c b/drivers/nfc/fdp/i2c.c
index 5e797d5..712936f 100644
--- a/drivers/nfc/fdp/i2c.c
+++ b/drivers/nfc/fdp/i2c.c
@@ -210,14 +210,14 @@ static irqreturn_t fdp_nci_i2c_irq_thread_fn(int irq, void *phy_id)
struct sk_buff *skb;
int r;

- client = phy->i2c_dev;
- dev_dbg(&client->dev, "%s\n", __func__);
-
if (!phy || irq != phy->i2c_dev->irq) {
WARN_ON_ONCE(1);
return IRQ_NONE;
}

+ client = phy->i2c_dev;
+ dev_dbg(&client->dev, "%s\n", __func__);
+
r = fdp_nci_i2c_read(phy, &skb);

if (r == -EREMOTEIO)
--
1.9.1