4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx> 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@xxxxxxxxxxxxxxx> Signed-off-by: Samuel Ortiz <sameo@xxxxxxxxxxxxxxx> Signed-off-by: Amit Pundir <amit.pundir@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/nfc/fdp/i2c.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/nfc/fdp/i2c.c +++ b/drivers/nfc/fdp/i2c.c @@ -210,14 +210,14 @@ static irqreturn_t fdp_nci_i2c_irq_threa 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)