12. Consider the following interrupt handler, what is wrong with this code? (5) static irgreturn_t phht_intr (int irq, void data) struct pci_device "dev data; struct phht_adapter *adapter pci_getdrvdata (dev) unsigned char *buffer; mutex_lock (sadapter->my mutex) adapter->ss_1 ist = knalloc (16, GFP_ATOMIC); mutex_unlock (&adapter->my_mutex) : return IRO HANDLED