[26/93] cciss: Make cciss_seq_show handle holes in the h->drv[] array

[Greg KH]

2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Stephen M. Cameron <scameron@xxxxxxxxxxxxxxxxxx>

commit 531c2dc70d339c5dfa8c3eb628c3459dc6f3a075 upstream.

It is possible (and expected) for there to be holes in the h->drv[]
array, that is, some elements may be NULL pointers.  cciss_seq_show
needs to be made aware of this possibility to avoid an Oops.

To reproduce the Oops which this fixes:

1) Create two "arrays" in the Array Configuratino Utility and
   several logical drives on each array.
2) cat /proc/driver/cciss/cciss* in an infinite loop
3) delete some of the logical drives in the first "array."

Signed-off-by: Stephen M. Cameron <scameron@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jens Axboe <jens.axboe@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/block/cciss.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -339,6 +339,9 @@ static int cciss_seq_show(struct seq_fil
 	if (*pos > h->highest_lun)
 		return 0;
 
+	if (drv == NULL) /* it's possible for h->drv[] to have holes. */
+		return 0;
+
 	if (drv->heads == 0)
 		return 0;
 


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