BUG null dereference in drivers/ata/sata_mv.c

[Alexander Strakh <strakh@ispras.ru>]

	KERNEL_VERSION: 2.6.32
	SUBJECT: null dereference in function mv_unexpected_intr
	DESCRIBE:
	In ./drivers/ata/sata_mv.c in function mv_port_intr 

1. If ap == NULL in line 2778, then we goto line 2779.
2. In line 2779 function mv_unexpected_intr(ap, 0) is called.
3. In line 2538 null dereference: "ap->link.eh_info"

2773 static void mv_port_intr(struct ata_port *ap, u32 port_cause)
2774 {
...
2778         if (!ap || (ap->flags & ATA_FLAG_DISABLED)) {
2779                 mv_unexpected_intr(ap, 0);
2780                 return;
2781         }
...
2809 }

2536 static void mv_unexpected_intr(struct ata_port *ap, int edma_was_enabled)
2537 {
2538         struct ata_eh_info *ehi = &ap->link.eh_info;
...
2555 }

Found by Linux Device Drivers Verification Project (Svace Detector)