[SCSI] mpt2sas: Null pointer deference possibility in mpt2sas_ctl_event_callback function

Added a check to identify if mpi_reply is NULL in mpt2sas_ctl_event_callback()
and return without proceeding if it is the case.

Also modified the following functions to return void instead of 0 or 1
as returning those values from events perspective doesn't make sense.
* _base_async_event()
* mpt2sas_ctl_event_callback()
* mpt2sas_scsih_event_callback()

Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/mpt2sas/mpt2sas_base.c

@@ -768,10 +768,9 @@ mpt2sas_base_done(struct MPT2SAS_ADAPTER *ioc, u16 smid, u8 msix_index,
  * @msix_index: MSIX table index supplied by the OS
  * @reply: reply message frame(lower 32bit addr)
  *
- * Return 1 meaning mf should be freed from _base_interrupt
- *        0 means the mf is freed from this function.
+ * Returns void.
  */
-static u8
+static void
 _base_async_event(struct MPT2SAS_ADAPTER *ioc, u8 msix_index, u32 reply)
 {
 	Mpi2EventNotificationReply_t *mpi_reply;
@@ -780,9 +779,9 @@ _base_async_event(struct MPT2SAS_ADAPTER *ioc, u8 msix_index, u32 reply)
 
 	mpi_reply = mpt2sas_base_get_reply_virt_addr(ioc, reply);
 	if (!mpi_reply)
-		return 1;
+		return;
 	if (mpi_reply->Function != MPI2_FUNCTION_EVENT_NOTIFICATION)
-		return 1;
+		return;
 #ifdef CONFIG_SCSI_MPT2SAS_LOGGING
 	_base_display_event_data(ioc, mpi_reply);
 #endif
@@ -812,7 +811,7 @@ _base_async_event(struct MPT2SAS_ADAPTER *ioc, u8 msix_index, u32 reply)
 	/* ctl callback handler */
 	mpt2sas_ctl_event_callback(ioc, msix_index, reply);
 
-	return 1;
+	return;
 }
 
 /**

drivers/scsi/mpt2sas/mpt2sas_base.h

@@ -1061,7 +1061,7 @@ void mpt2sas_base_update_missing_delay(struct MPT2SAS_ADAPTER *ioc,
 int mpt2sas_port_enable(struct MPT2SAS_ADAPTER *ioc);
 
 /* scsih shared API */
-u8 mpt2sas_scsih_event_callback(struct MPT2SAS_ADAPTER *ioc, u8 msix_index,
+void mpt2sas_scsih_event_callback(struct MPT2SAS_ADAPTER *ioc, u8 msix_index,
     u32 reply);
 int mpt2sas_scsih_issue_tm(struct MPT2SAS_ADAPTER *ioc, u16 handle,
 	uint channel, uint id, uint lun, u8 type, u16 smid_task,
@@ -1144,7 +1144,7 @@ void mpt2sas_ctl_exit(void);
 u8 mpt2sas_ctl_done(struct MPT2SAS_ADAPTER *ioc, u16 smid, u8 msix_index,
     u32 reply);
 void mpt2sas_ctl_reset_handler(struct MPT2SAS_ADAPTER *ioc, int reset_phase);
-u8 mpt2sas_ctl_event_callback(struct MPT2SAS_ADAPTER *ioc, u8 msix_index,
+void mpt2sas_ctl_event_callback(struct MPT2SAS_ADAPTER *ioc, u8 msix_index,
     u32 reply);
 void mpt2sas_ctl_add_to_event_log(struct MPT2SAS_ADAPTER *ioc,
     Mpi2EventNotificationReply_t *mpi_reply);

drivers/scsi/mpt2sas/mpt2sas_ctl.c

@@ -397,18 +397,22 @@ mpt2sas_ctl_add_to_event_log(struct MPT2SAS_ADAPTER *ioc,
  * This function merely adds a new work task into ioc->firmware_event_thread.
  * The tasks are worked from _firmware_event_work in user context.
  *
- * Return 1 meaning mf should be freed from _base_interrupt
- *        0 means the mf is freed from this function.
+ * Returns void.
  */
-u8
+void
 mpt2sas_ctl_event_callback(struct MPT2SAS_ADAPTER *ioc, u8 msix_index,
 	u32 reply)
 {
 	Mpi2EventNotificationReply_t *mpi_reply;
 
 	mpi_reply = mpt2sas_base_get_reply_virt_addr(ioc, reply);
+	if (unlikely(!mpi_reply)) {
+		printk(MPT2SAS_ERR_FMT "mpi_reply not valid at %s:%d/%s()!\n",
+		    ioc->name, __FILE__, __LINE__, __func__);
+		return;
+	}
 	mpt2sas_ctl_add_to_event_log(ioc, mpi_reply);
-	return 1;
+	return;
 }
 
 /**

drivers/scsi/mpt2sas/mpt2sas_scsih.c

@@ -7471,10 +7471,9 @@ _firmware_event_work(struct work_struct *work)
  * This function merely adds a new work task into ioc->firmware_event_thread.
  * The tasks are worked from _firmware_event_work in user context.
  *
- * Return 1 meaning mf should be freed from _base_interrupt
- *        0 means the mf is freed from this function.
+ * Returns void.
  */
-u8
+void
 mpt2sas_scsih_event_callback(struct MPT2SAS_ADAPTER *ioc, u8 msix_index,
 	u32 reply)
 {
@@ -7485,14 +7484,14 @@ mpt2sas_scsih_event_callback(struct MPT2SAS_ADAPTER *ioc, u8 msix_index,
 
 	/* events turned off due to host reset or driver unloading */
 	if (ioc->remove_host || ioc->pci_error_recovery)
-		return 1;
+		return;
 
 	mpi_reply = mpt2sas_base_get_reply_virt_addr(ioc, reply);
 
 	if (unlikely(!mpi_reply)) {
 		printk(MPT2SAS_ERR_FMT "mpi_reply not valid at %s:%d/%s()!\n",
 		    ioc->name, __FILE__, __LINE__, __func__);
-		return 1;
+		return;
 	}
 
 	event = le16_to_cpu(mpi_reply->Event);
@@ -7507,11 +7506,11 @@ mpt2sas_scsih_event_callback(struct MPT2SAS_ADAPTER *ioc, u8 msix_index,
 
 		if (baen_data->Primitive !=
 		    MPI2_EVENT_PRIMITIVE_ASYNCHRONOUS_EVENT)
-			return 1;
+			return;
 
 		if (ioc->broadcast_aen_busy) {
 			ioc->broadcast_aen_pending++;
-			return 1;
+			return;
 		} else
 			ioc->broadcast_aen_busy = 1;
 		break;
@@ -7587,14 +7586,14 @@ mpt2sas_scsih_event_callback(struct MPT2SAS_ADAPTER *ioc, u8 msix_index,
 		break;
 
 	default: /* ignore the rest */
-		return 1;
+		return;
 	}
 
 	fw_event = kzalloc(sizeof(struct fw_event_work), GFP_ATOMIC);
 	if (!fw_event) {
 		printk(MPT2SAS_ERR_FMT "failure at %s:%d/%s()!\n",
 		    ioc->name, __FILE__, __LINE__, __func__);
-		return 1;
+		return;
 	}
 	sz = le16_to_cpu(mpi_reply->EventDataLength) * 4;
 	fw_event->event_data = kzalloc(sz, GFP_ATOMIC);
@@ -7602,7 +7601,7 @@ mpt2sas_scsih_event_callback(struct MPT2SAS_ADAPTER *ioc, u8 msix_index,
 		printk(MPT2SAS_ERR_FMT "failure at %s:%d/%s()!\n",
 		    ioc->name, __FILE__, __LINE__, __func__);
 		kfree(fw_event);
-		return 1;
+		return;
 	}
 
 	memcpy(fw_event->event_data, mpi_reply->EventData,
@@ -7612,7 +7611,7 @@ mpt2sas_scsih_event_callback(struct MPT2SAS_ADAPTER *ioc, u8 msix_index,
 	fw_event->VP_ID = mpi_reply->VP_ID;
 	fw_event->event = event;
 	_scsih_fw_event_add(ioc, fw_event);
-	return 1;
+	return;
 }
 
 /* shost template */