scsi: qla2xxx: Fix panic in qla_dfs_tgt_counters_show

When trying to display tgt_counters in the debugfs, a panic can result.

There is no null check for qpair after it is assigned in the for-loop.
Unless vha->hw->queue_pair_map array is completely filled with entries, the
system will panic dereferencing a null pointer.

Signed-off-by: Bill Kuzeja <william.kuzeja@stratus.com>
Acked-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/qla2xxx/qla_dfs.c b/drivers/scsi/qla2xxx/qla_dfs.c
index ead1728..5819a45 100644 (file)
--- a/drivers/scsi/qla2xxx/qla_dfs.c
+++ b/drivers/scsi/qla2xxx/qla_dfs.c
@@ -193,6 +193,8 @@ qla_dfs_tgt_counters_show(struct seq_file *s, void *unused)
 
        for (i = 0; i < vha->hw->max_qpairs; i++) {
                qpair = vha->hw->queue_pair_map[i];
+               if (!qpair)
+                       continue;
                qla_core_sbt_cmd += qpair->tgt_counters.qla_core_sbt_cmd;
                core_qla_que_buf += qpair->tgt_counters.core_qla_que_buf;
                qla_core_ret_ctio += qpair->tgt_counters.qla_core_ret_ctio;