diff --git a/drivers/scsi/mpt2sas/mpt2sas_base.c b/drivers/scsi/mpt2sas/mpt2sas_base.c
index 11248de..d2a498c 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_base.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_base.c
@@ -108,13 +108,18 @@ _scsih_set_fwfault_debug(const char *val, struct kernel_param *kp)
 {
 	int ret = param_set_int(val, kp);
 	struct MPT2SAS_ADAPTER *ioc;
+	unsigned long flags;
 
 	if (ret)
 		return ret;
 
+	/* global ioc spinlock to protect controller list on list operations */
+	mpt2sas_initialize_gioc_lock();
 	printk(KERN_INFO "setting fwfault_debug(%d)\n", mpt2sas_fwfault_debug);
+	spin_lock_irqsave(&gioc_lock, flags);
 	list_for_each_entry(ioc, &mpt2sas_ioc_list, list)
 		ioc->fwfault_debug = mpt2sas_fwfault_debug;
+	spin_unlock_irqrestore(&gioc_lock, flags);
 	return 0;
 }
 
@@ -4436,6 +4441,9 @@ mpt2sas_base_free_resources(struct MPT2SAS_ADAPTER *ioc)
 	    __func__));
 
 	if (ioc->chip_phys && ioc->chip) {
+		/* synchronizing freeing resource with pci_access_mutex lock */
+		if (ioc->is_warpdrive)
+			mutex_lock(&ioc->pci_access_mutex);
 		_base_mask_interrupts(ioc);
 		ioc->shost_recovery = 1;
 		_base_make_ioc_ready(ioc, CAN_SLEEP, SOFT_RESET);
@@ -4454,6 +4462,8 @@ mpt2sas_base_free_resources(struct MPT2SAS_ADAPTER *ioc)
 		pci_disable_pcie_error_reporting(pdev);
 		pci_disable_device(pdev);
 	}
+	if (ioc->is_warpdrive)
+		mutex_unlock(&ioc->pci_access_mutex);
 	return;
 }
 
diff --git a/drivers/scsi/mpt2sas/mpt2sas_base.h b/drivers/scsi/mpt2sas/mpt2sas_base.h
index caff8d1..a0d26f0 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_base.h
+++ b/drivers/scsi/mpt2sas/mpt2sas_base.h
@@ -799,6 +799,12 @@ typedef void (*MPT2SAS_FLUSH_RUNNING_CMDS)(struct MPT2SAS_ADAPTER *ioc);
  * @delayed_tr_list: target reset link list
  * @delayed_tr_volume_list: volume target reset link list
  * @@temp_sensors_count: flag to carry the number of temperature sensors
+ * @pci_access_mutex: Mutex to synchronize ioctl,sysfs show path and
+ * pci resource handling. PCI resource freeing will lead to free
+ * vital hardware/memory resource, which might be in use by cli/sysfs
+ * path functions resulting in Null pointer reference followed by kernel
+ * crash. To avoid the above race condition we use mutex syncrhonization
+ * which ensures the syncrhonization between cli/sysfs_show path
  */
 struct MPT2SAS_ADAPTER {
 	struct list_head list;
@@ -1015,6 +1021,7 @@ struct MPT2SAS_ADAPTER {
 	u8		mfg_pg10_hide_flag;
 	u8		hide_drives;
 
+	struct mutex pci_access_mutex;
 };
 
 typedef u8 (*MPT_CALLBACK)(struct MPT2SAS_ADAPTER *ioc, u16 smid, u8 msix_index,
@@ -1023,6 +1030,17 @@ typedef u8 (*MPT_CALLBACK)(struct MPT2SAS_ADAPTER *ioc, u16 smid, u8 msix_index,
 
 /* base shared API */
 extern struct list_head mpt2sas_ioc_list;
+/* spinlock on list operations over IOCs
++ * Case: when multiple warpdrive cards(IOCs) are in use
++ * Each IOC will added to the ioc list stucture on initialization.
++ * Watchdog threads run at regular intervals to check IOC for any
++ * fault conditions which will trigger the dead_ioc thread to
++ * deallocate pci resource, resulting deleting the IOC netry from list,
++ * this deletion need to protected by spinlock to enusre that
++ * ioc removal is syncrhonized, if not synchronized it might lead to
++ * list_del corruption as the ioc list is traversed in cli path
++ */
+extern spinlock_t gioc_lock;
 void mpt2sas_base_start_watchdog(struct MPT2SAS_ADAPTER *ioc);
 void mpt2sas_base_stop_watchdog(struct MPT2SAS_ADAPTER *ioc);
 
@@ -1099,7 +1117,7 @@ struct _sas_device *mpt2sas_scsih_sas_device_find_by_sas_address(
     struct MPT2SAS_ADAPTER *ioc, u64 sas_address);
 
 void mpt2sas_port_enable_complete(struct MPT2SAS_ADAPTER *ioc);
-
+void mpt2sas_initialize_gioc_lock(void);
 void mpt2sas_scsih_reset_handler(struct MPT2SAS_ADAPTER *ioc, int reset_phase);
 
 /* config shared API */
diff --git a/drivers/scsi/mpt2sas/mpt2sas_ctl.c b/drivers/scsi/mpt2sas/mpt2sas_ctl.c
index 4e50960..5345368 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_ctl.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_ctl.c
@@ -427,13 +427,17 @@ static int
 _ctl_verify_adapter(int ioc_number, struct MPT2SAS_ADAPTER **iocpp)
 {
 	struct MPT2SAS_ADAPTER *ioc;
-
+	unsigned long flags;
+	/* global ioc lock to protect controller on list operations */
+	spin_lock_irqsave(&gioc_lock, flags);
 	list_for_each_entry(ioc, &mpt2sas_ioc_list, list) {
 		if (ioc->id != ioc_number)
 			continue;
+		spin_unlock_irqrestore(&gioc_lock, flags);
 		*iocpp = ioc;
 		return ioc_number;
 	}
+	spin_unlock_irqrestore(&gioc_lock, flags);
 	*iocpp = NULL;
 	return -1;
 }
@@ -519,13 +523,19 @@ static unsigned int
 _ctl_poll(struct file *filep, poll_table *wait)
 {
 	struct MPT2SAS_ADAPTER *ioc;
+	unsigned long flags;
 
 	poll_wait(filep, &ctl_poll_wait, wait);
 
+	/* global ioc lock to protect controller on list operations */
+	spin_lock_irqsave(&gioc_lock, flags);
 	list_for_each_entry(ioc, &mpt2sas_ioc_list, list) {
-		if (ioc->aen_event_read_flag)
+		if (ioc->aen_event_read_flag) {
+			spin_unlock_irqrestore(&gioc_lock, flags);
 			return POLLIN | POLLRDNORM;
+		}
 	}
+	spin_unlock_irqrestore(&gioc_lock, flags);
 	return 0;
 }
 
@@ -2168,15 +2178,30 @@ _ctl_ioctl_main(struct file *file, unsigned int cmd, void __user *arg,
 
 	if (_ctl_verify_adapter(ioctl_header.ioc_number, &ioc) == -1 || !ioc)
 		return -ENODEV;
-	if (ioc->shost_recovery || ioc->pci_error_recovery ||
-	    ioc->is_driver_loading)
-		return -EAGAIN;
+	if (!ioc->is_warpdrive) {
+		if (ioc->shost_recovery || ioc->pci_error_recovery ||
+			ioc->is_driver_loading)
+			return -EAGAIN;
+	} else {
+		/* pci_access_mutex lock acquired by ioctl path */
+		mutex_lock(&ioc->pci_access_mutex);
+		if (ioc->shost_recovery || ioc->pci_error_recovery ||
+			ioc->is_driver_loading || ioc->remove_host) {
+			mutex_unlock(&ioc->pci_access_mutex);
+			return -EAGAIN;
+		}
+	}
 
 	state = (file->f_flags & O_NONBLOCK) ? NON_BLOCKING : BLOCKING;
 	if (state == NON_BLOCKING) {
-		if (!mutex_trylock(&ioc->ctl_cmds.mutex))
+		if (!mutex_trylock(&ioc->ctl_cmds.mutex)) {
+			if (ioc->is_warpdrive)
+				mutex_unlock(&ioc->pci_access_mutex);
 			return -EAGAIN;
+		}
 	} else if (mutex_lock_interruptible(&ioc->ctl_cmds.mutex)) {
+		if (ioc->is_warpdrive)
+			mutex_unlock(&ioc->pci_access_mutex);
 		return -ERESTARTSYS;
 	}
 
@@ -2258,6 +2283,8 @@ _ctl_ioctl_main(struct file *file, unsigned int cmd, void __user *arg,
 	}
 
 	mutex_unlock(&ioc->ctl_cmds.mutex);
+	if (ioc->is_warpdrive)
+		mutex_unlock(&ioc->pci_access_mutex);
 	return ret;
 }
 
@@ -2710,6 +2737,13 @@ _ctl_BRM_status_show(struct device *cdev, struct device_attribute *attr,
 		printk(MPT2SAS_ERR_FMT "%s: BRM attribute is only for"\
 		    "warpdrive\n", ioc->name, __func__);
 		goto out;
+	} else {
+		/* pci_access_mutex lock acquired by sysfs show path */
+		mutex_lock(&ioc->pci_access_mutex);
+		if (ioc->pci_error_recovery || ioc->remove_host) {
+			mutex_unlock(&ioc->pci_access_mutex);
+			return 0;
+		}
 	}
 
 	/* allocate upto GPIOVal 36 entries */
@@ -2749,6 +2783,8 @@ _ctl_BRM_status_show(struct device *cdev, struct device_attribute *attr,
 
  out:
 	kfree(io_unit_pg3);
+	if (ioc->is_warpdrive)
+		mutex_unlock(&ioc->pci_access_mutex);
 	return rc;
 }
 static DEVICE_ATTR(BRM_status, S_IRUGO, _ctl_BRM_status_show, NULL);
diff --git a/drivers/scsi/mpt2sas/mpt2sas_scsih.c b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
index 3f26147..ef20ed3 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_scsih.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
@@ -79,7 +79,8 @@ static int _scsih_scan_finished(struct Scsi_Host *shost, unsigned long time);
 
 /* global parameters */
 LIST_HEAD(mpt2sas_ioc_list);
-
+/* global ioc lock for list operations */
+spinlock_t gioc_lock;
 /* local parameters */
 static u8 scsi_io_cb_idx = -1;
 static u8 tm_cb_idx = -1;
@@ -279,6 +280,20 @@ static struct pci_device_id scsih_pci_table[] = {
 MODULE_DEVICE_TABLE(pci, scsih_pci_table);
 
 /**
+ * mpt2sas_initialize_gioc_lock - initialize the gobal ioc lock
+ */
+void
+mpt2sas_initialize_gioc_lock(void)
+{
+	static int gioc_lock_initialize;
+
+	if (!gioc_lock_initialize) {
+		spin_lock_init(&gioc_lock);
+		gioc_lock_initialize = 1;
+	}
+}
+
+/**
  * _scsih_set_debug_level - global setting of ioc->logging_level.
  *
  * Note: The logging levels are defined in mpt2sas_debug.h.
@@ -288,13 +303,17 @@ _scsih_set_debug_level(const char *val, struct kernel_param *kp)
 {
 	int ret = param_set_int(val, kp);
 	struct MPT2SAS_ADAPTER *ioc;
+	unsigned long flags;
 
 	if (ret)
 		return ret;
 
+	mpt2sas_initialize_gioc_lock();
 	printk(KERN_INFO "setting logging_level(0x%08x)\n", logging_level);
+	spin_lock_irqsave(&gioc_lock, flags);
 	list_for_each_entry(ioc, &mpt2sas_ioc_list, list)
 		ioc->logging_level = logging_level;
+	spin_unlock_irqrestore(&gioc_lock, flags);
 	return 0;
 }
 module_param_call(logging_level, _scsih_set_debug_level, param_get_int,
@@ -7867,7 +7886,9 @@ _scsih_remove(struct pci_dev *pdev)
 	sas_remove_host(shost);
 	scsi_remove_host(shost);
 	mpt2sas_base_detach(ioc);
+	spin_lock_irqsave(&gioc_lock, flags);
 	list_del(&ioc->list);
+	spin_unlock_irqrestore(&gioc_lock, flags);
 	scsi_host_put(shost);
 }
 
@@ -8132,6 +8153,7 @@ _scsih_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	struct MPT2SAS_ADAPTER *ioc;
 	struct Scsi_Host *shost;
 	int rv;
+	unsigned long flags;
 
 	shost = scsi_host_alloc(&scsih_driver_template,
 	    sizeof(struct MPT2SAS_ADAPTER));
@@ -8142,7 +8164,9 @@ _scsih_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	ioc = shost_priv(shost);
 	memset(ioc, 0, sizeof(struct MPT2SAS_ADAPTER));
 	INIT_LIST_HEAD(&ioc->list);
+	spin_lock_irqsave(&gioc_lock, flags);
 	list_add_tail(&ioc->list, &mpt2sas_ioc_list);
+	spin_unlock_irqrestore(&gioc_lock, flags);
 	ioc->shost = shost;
 	ioc->id = mpt_ids++;
 	sprintf(ioc->name, "%s%d", MPT2SAS_DRIVER_NAME, ioc->id);
@@ -8167,6 +8191,9 @@ _scsih_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	ioc->schedule_dead_ioc_flush_running_cmds = &_scsih_flush_running_cmds;
 	/* misc semaphores and spin locks */
 	mutex_init(&ioc->reset_in_progress_mutex);
+	/* initializing pci_access_mutex lock */
+	if (ioc->is_warpdrive)
+		mutex_init(&ioc->pci_access_mutex);
 	spin_lock_init(&ioc->ioc_reset_in_progress_lock);
 	spin_lock_init(&ioc->scsi_lookup_lock);
 	spin_lock_init(&ioc->sas_device_lock);
@@ -8269,7 +8296,9 @@ _scsih_probe(struct pci_dev *pdev, const struct pci_device_id *id)
  out_attach_fail:
 	destroy_workqueue(ioc->firmware_event_thread);
  out_thread_fail:
+	spin_lock_irqsave(&gioc_lock, flags);
 	list_del(&ioc->list);
+	spin_unlock_irqrestore(&gioc_lock, flags);
 	scsi_host_put(shost);
 	return rv;
 }
@@ -8506,6 +8535,7 @@ _scsih_init(void)
 		return -ENODEV;
 	}
 
+	mpt2sas_initialize_gioc_lock();
 	mpt2sas_base_initialize_callback_handler();
 
 	 /* queuecommand callback hander */
