diff --git a/drivers/scsi/sata_mv.c b/drivers/scsi/sata_mv.c
index 9b8bca1ac1f0..f16f92a6ec0f 100644
--- a/drivers/scsi/sata_mv.c
+++ b/drivers/scsi/sata_mv.c
@@ -2035,6 +2035,7 @@ static void mv_phy_reset(struct ata_port *ap)
 static void mv_eng_timeout(struct ata_port *ap)
 {
 	struct ata_queued_cmd *qc;
+	unsigned long flags;
 
 	printk(KERN_ERR "ata%u: Entering mv_eng_timeout\n",ap->id);
 	DPRINTK("All regs @ start of eng_timeout\n");
@@ -2046,8 +2047,10 @@ static void mv_eng_timeout(struct ata_port *ap)
 	       ap->host_set->mmio_base, ap, qc, qc->scsicmd,
 	       &qc->scsicmd->cmnd);
 
+	spin_lock_irqsave(&ap->host_set->lock, flags);
 	mv_err_intr(ap, 0);
 	mv_stop_and_reset(ap);
+	spin_unlock_irqrestore(&ap->host_set->lock, flags);
 
 	WARN_ON(!(qc->flags & ATA_QCFLAG_ACTIVE));
 	if (qc->flags & ATA_QCFLAG_ACTIVE) {