diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 22ce6accbc5b..f0753f5e57a8 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2833,6 +2833,24 @@ static void ata_dev_config_cpr(struct ata_device *dev)
 	if (!nr_cpr)
 		goto out;
 
+	/*
+	 * The device reports the number of CPR descriptors independently of the
+	 * log size, and that count is also used to emit VPD page B9h into the
+	 * fixed-size rbuf. Reject a count larger than what that buffer can hold
+	 * (ATA_DEV_MAX_CPR) or larger than the log the device actually returned.
+	 */
+	if (nr_cpr > ATA_DEV_MAX_CPR) {
+		ata_dev_warn(dev,
+			     "Too many concurrent positioning ranges\n");
+		goto out;
+	}
+
+	if (buf_len < 64 + (size_t)nr_cpr * 32) {
+		ata_dev_warn(dev,
+			     "Invalid number of concurrent positioning ranges\n");
+		goto out;
+	}
+
 	cpr_log = kzalloc(struct_size(cpr_log, cpr, nr_cpr), GFP_KERNEL);
 	if (!cpr_log)
 		goto out;
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 46ef1ef6f812..a7916b50cbfc 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -37,8 +37,6 @@
 #include "libata.h"
 #include "libata-transport.h"
 
-#define ATA_SCSI_RBUF_SIZE	2048
-
 static DEFINE_SPINLOCK(ata_scsi_rbuf_lock);
 static u8 ata_scsi_rbuf[ATA_SCSI_RBUF_SIZE];
 
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 0002994ddfc9..56c4136b7417 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -144,6 +144,15 @@ static inline void ata_acpi_bind_dev(struct ata_device *dev) {}
 #endif
 
 /* libata-scsi.c */
+#define ATA_SCSI_RBUF_SIZE	2048
+
+/*
+ * Maximum number of concurrent positioning ranges (CPR) supported. The ACS
+ * specifications allow up to 255, but we limit this to the number of CPR
+ * descriptors that fit in the rbuf buffer used to emit VPD page B9h.
+ */
+#define ATA_DEV_MAX_CPR		min(255, ((ATA_SCSI_RBUF_SIZE - 64) / 32))
+
 extern struct ata_device *ata_scsi_find_dev(struct ata_port *ap,
 					    const struct scsi_device *scsidev);
 extern int ata_scsi_add_hosts(struct ata_host *host,