[PATCH] [251/275] ses: Avoid kernel panic when lun 0 is not mapped

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Krishnasamy, Somasundaram <Somasundaram.Krishnasamy@xxxxxxx>

commit d1e12de804f9d8ad114786ca7c2ce593cba79891 upstream.

During device discovery, scsi mid layer sends INQUIRY command to LUN
0. If the LUN 0 is not mapped to host, it creates a temporary
scsi_device with LUN id 0 and sends REPORT_LUNS command to it. After
the REPORT_LUNS succeeds, it walks through the LUN table and adds each
LUN found to sysfs. At the end of REPORT_LUNS lun table scan, it will
delete the temporary scsi_device of LUN 0.

When scsi devices are added to sysfs, it calls add_dev function of all
the registered class interfaces. If ses driver has been registered,
ses_intf_add() of ses module will be called. This function calls
scsi_device_enclosure() to check the inquiry data for EncServ
bit. Since inquiry was not allocated for temporary LUN 0 scsi_device,
it will cause NULL pointer exception.

To fix the problem, sdev->inquiry is checked for NULL before reading it.

Signed-off-by: Somasundaram Krishnasamy <Somasundaram.Krishnasamy@xxxxxxx>
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
Signed-off-by: James Bottomley <James.Bottomley@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

---
 include/scsi/scsi_device.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6.35.y/include/scsi/scsi_device.h
===================================================================
--- linux-2.6.35.y.orig/include/scsi/scsi_device.h	2011-03-29 22:50:10.926978825 -0700
+++ linux-2.6.35.y/include/scsi/scsi_device.h	2011-03-29 23:03:03.501210582 -0700
@@ -451,7 +451,7 @@
 }
 static inline int scsi_device_enclosure(struct scsi_device *sdev)
 {
-	return sdev->inquiry[6] & (1<<6);
+	return sdev->inquiry ? (sdev->inquiry[6] & (1<<6)) : 1;
 }
 
 static inline int scsi_device_protection(struct scsi_device *sdev)
--
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