[PATCH] perf/arm-cmn: Fix invalid pointer when access dtc object sharing the same IRQ number

[Tuan Phan]

When multiple dtcs share the same IRQ number, the irq_friend which
used to refer to dtc object gets calculated incorrect which leads
to invalid pointer.

Fixes: 0ba64770a2f2 ("perf: Add Arm CMN-600 PMU driver")

Signed-off-by: Tuan Phan <tuanphan at os.amperecomputing.com>
---
 drivers/perf/arm-cmn.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
index 56a5c35..49016f2 100644
--- a/drivers/perf/arm-cmn.c
+++ b/drivers/perf/arm-cmn.c
@@ -1212,7 +1212,7 @@ static int arm_cmn_init_irqs(struct arm_cmn *cmn)
 		irq = cmn->dtc[i].irq;
 		for (j = i; j--; ) {
 			if (cmn->dtc[j].irq == irq) {
-				cmn->dtc[j].irq_friend = j - i;
+				cmn->dtc[j].irq_friend = i - j;
 				goto next;
 			}
 		}
-- 
2.7.4