Commit 6c1e803e authored by James Smart's avatar James Smart Committed by Martin K. Petersen
Browse files

scsi: lpfc: Fix kernel crash at lpfc_nvme_info_show during remote port bounce 

When reading sysfs nvme_info file while a remote port leaves and comes
back, a NULL pointer is encountered. The issue is due to ndlp list
corruption as the the nvme_info_show does not use the same lock as the rest
of the code.

Correct by removing the rcu_xxx_lock calls and replace by the host_lock and
phba->hbaLock spinlocks that are used by the rest of the driver.  Given
we're called from sysfs, we are safe to use _irq rather than _irqsave.

Link: https://lore.kernel.org/r/20191105005708.7399-4-jsmart2021@gmail.com


Signed-off-by: default avatarDick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: default avatarJames Smart <jsmart2021@gmail.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 6bfb1620

drivers/scsi/lpfc/lpfc_attr.c

+20 −20
Original line number Diff line number Diff line
@@ -176,7 +176,6 @@ lpfc_nvme_info_show(struct device *dev, struct device_attribute *attr, 
	int i;

	int len = 0;

	char tmp[LPFC_MAX_NVME_INFO_TMP_LEN] = {0};

	unsigned long iflags = 0;



	if (!(vport->cfg_enable_fc4_type & LPFC_ENABLE_NVME)) {

		len = scnprintf(buf, PAGE_SIZE, "NVME Disabled\n");
@@ -347,7 +346,6 @@ lpfc_nvme_info_show(struct device *dev, struct device_attribute *attr, 
	if (strlcat(buf, "\nNVME Initiator Enabled\n", PAGE_SIZE) >= PAGE_SIZE)

		goto buffer_done;



	rcu_read_lock();

	scnprintf(tmp, sizeof(tmp),

		  "XRI Dist lpfc%d Total %d IO %d ELS %d\n",

		  phba->brd_no,
@@ -355,7 +353,7 @@ lpfc_nvme_info_show(struct device *dev, struct device_attribute *attr, 
		  phba->sli4_hba.io_xri_max,

		  lpfc_sli4_get_els_iocb_cnt(phba));

	if (strlcat(buf, tmp, PAGE_SIZE) >= PAGE_SIZE)

		goto rcu_unlock_buf_done;

		goto buffer_done;



	/* Port state is only one of two values for now. */

	if (localport->port_id)
@@ -371,15 +369,17 @@ lpfc_nvme_info_show(struct device *dev, struct device_attribute *attr, 
		  wwn_to_u64(vport->fc_nodename.u.wwn),

		  localport->port_id, statep);

	if (strlcat(buf, tmp, PAGE_SIZE) >= PAGE_SIZE)

		goto rcu_unlock_buf_done;

		goto buffer_done;



	spin_lock_irq(shost->host_lock);



	list_for_each_entry(ndlp, &vport->fc_nodes, nlp_listp) {

		nrport = NULL;

		spin_lock_irqsave(&vport->phba->hbalock, iflags);

		spin_lock(&vport->phba->hbalock);

		rport = lpfc_ndlp_get_nrport(ndlp);

		if (rport)

			nrport = rport->remoteport;

		spin_unlock_irqrestore(&vport->phba->hbalock, iflags);

		spin_unlock(&vport->phba->hbalock);

		if (!nrport)

			continue;
@@ -398,39 +398,39 @@ lpfc_nvme_info_show(struct device *dev, struct device_attribute *attr, 


		/* Tab in to show lport ownership. */

		if (strlcat(buf, "NVME RPORT       ", PAGE_SIZE) >= PAGE_SIZE)

			goto rcu_unlock_buf_done;

			goto unlock_buf_done;

		if (phba->brd_no >= 10) {

			if (strlcat(buf, " ", PAGE_SIZE) >= PAGE_SIZE)

				goto rcu_unlock_buf_done;

				goto unlock_buf_done;

		}



		scnprintf(tmp, sizeof(tmp), "WWPN x%llx ",

			  nrport->port_name);

		if (strlcat(buf, tmp, PAGE_SIZE) >= PAGE_SIZE)

			goto rcu_unlock_buf_done;

			goto unlock_buf_done;



		scnprintf(tmp, sizeof(tmp), "WWNN x%llx ",

			  nrport->node_name);

		if (strlcat(buf, tmp, PAGE_SIZE) >= PAGE_SIZE)

			goto rcu_unlock_buf_done;

			goto unlock_buf_done;



		scnprintf(tmp, sizeof(tmp), "DID x%06x ",

			  nrport->port_id);

		if (strlcat(buf, tmp, PAGE_SIZE) >= PAGE_SIZE)

			goto rcu_unlock_buf_done;

			goto unlock_buf_done;



		/* An NVME rport can have multiple roles. */

		if (nrport->port_role & FC_PORT_ROLE_NVME_INITIATOR) {

			if (strlcat(buf, "INITIATOR ", PAGE_SIZE) >= PAGE_SIZE)

				goto rcu_unlock_buf_done;

				goto unlock_buf_done;

		}

		if (nrport->port_role & FC_PORT_ROLE_NVME_TARGET) {

			if (strlcat(buf, "TARGET ", PAGE_SIZE) >= PAGE_SIZE)

				goto rcu_unlock_buf_done;

				goto unlock_buf_done;

		}

		if (nrport->port_role & FC_PORT_ROLE_NVME_DISCOVERY) {

			if (strlcat(buf, "DISCSRVC ", PAGE_SIZE) >= PAGE_SIZE)

				goto rcu_unlock_buf_done;

				goto unlock_buf_done;

		}

		if (nrport->port_role & ~(FC_PORT_ROLE_NVME_INITIATOR |

					  FC_PORT_ROLE_NVME_TARGET |
@@ -438,14 +438,14 @@ lpfc_nvme_info_show(struct device *dev, struct device_attribute *attr, 
			scnprintf(tmp, sizeof(tmp), "UNKNOWN ROLE x%x",

				  nrport->port_role);

			if (strlcat(buf, tmp, PAGE_SIZE) >= PAGE_SIZE)

				goto rcu_unlock_buf_done;

				goto unlock_buf_done;

		}



		scnprintf(tmp, sizeof(tmp), "%s\n", statep);

		if (strlcat(buf, tmp, PAGE_SIZE) >= PAGE_SIZE)

			goto rcu_unlock_buf_done;

			goto unlock_buf_done;

	}

	rcu_read_unlock();

	spin_unlock_irq(shost->host_lock);



	if (!lport)

		goto buffer_done;
@@ -505,11 +505,11 @@ lpfc_nvme_info_show(struct device *dev, struct device_attribute *attr, 
		  atomic_read(&lport->cmpl_fcp_err));

	strlcat(buf, tmp, PAGE_SIZE);



	/* RCU is already unlocked. */

	/* host_lock is already unlocked. */

	goto buffer_done;



 rcu_unlock_buf_done:

	rcu_read_unlock();

 unlock_buf_done:

	spin_unlock_irq(shost->host_lock);



 buffer_done:

	len = strnlen(buf, PAGE_SIZE);

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