[ 3.8.y.z extended stable ] Patch "[SCSI] mpt3sas: fix for kernel panic when driver loads with HBA" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    [SCSI] mpt3sas: fix for kernel panic when driver loads with HBA

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.5.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From ab7eb188432ac54727906fc42874624863e9b0f1 Mon Sep 17 00:00:00 2001
From: Sreekanth Reddy <Sreekanth.Reddy at lsi.com>
Date: Sat, 29 Jun 2013 03:52:03 +0530
Subject: [SCSI] mpt3sas: fix for kernel panic when driver loads with HBA
 conected to non LUN 0 configured expander

commit b65cfedf4560af65305bd7b3b9f26c02c6fb3660 upstream.

With some enclosures when LUN 0 is not created but LUN 1 or LUN X is created
then SCSI scan procedure calls target_alloc, slave_alloc call back functions
for LUN 0 and slave_destory() for same LUN 0.

In these kind of cases within slave_destroy, pointer to scsi_target in
_sas_device structure is set to NULL, following which when slave_alloc for LUN
1 is called then starget would not be set properly for this LUN.  So,
scsi_target pointer pointing to NULL value would lead to a crash later in the
discovery procedure.

To solve this issue set the sas_device's scsi_target pointer to scsi_device's
scsi_target if it is NULL earlier in slave_alloc callback function.

Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy at lsi.com>
Signed-off-by: James Bottomley <JBottomley at Parallels.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/scsi/mpt3sas/mpt3sas_scsih.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
index 6421a06..34b229a 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -1274,6 +1274,7 @@ _scsih_slave_alloc(struct scsi_device *sdev)
 	struct MPT3SAS_DEVICE *sas_device_priv_data;
 	struct scsi_target *starget;
 	struct _raid_device *raid_device;
+	struct _sas_device *sas_device;
 	unsigned long flags;

 	sas_device_priv_data = kzalloc(sizeof(struct scsi_device), GFP_KERNEL);
@@ -1302,6 +1303,19 @@ _scsih_slave_alloc(struct scsi_device *sdev)
 		spin_unlock_irqrestore(&ioc->raid_device_lock, flags);
 	}

+	if (!(sas_target_priv_data->flags & MPT_TARGET_FLAGS_VOLUME)) {
+		spin_lock_irqsave(&ioc->sas_device_lock, flags);
+		sas_device = mpt3sas_scsih_sas_device_find_by_sas_address(ioc,
+					sas_target_priv_data->sas_address);
+		if (sas_device && (sas_device->starget == NULL)) {
+			sdev_printk(KERN_INFO, sdev,
+			"%s : sas_device->starget set to starget @ %d\n",
+				__func__, __LINE__);
+			sas_device->starget = starget;
+		}
+		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
+	}
+
 	return 0;
 }

--
1.8.1.2