nfc: fdp: fix NULL pointer dereference

commit b6355fb3f5f40bbce165847d277e64896cab8f95 upstream.

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@codethink.co.uk>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nfc/fdp/i2c.c b/drivers/nfc/fdp/i2c.c
index 532db28145c7dafee6350fb44ca52ca4052644e4..a5d7332dfce51a12571f3fb96d87e419be5d4b98 100644 (file)
--- 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)