Re: [PATCH] perf/arm-cmn: Fail DTC counter allocation correctly
From: Ilkka Koskinen
Date: Mon Dec 11 2023 - 21:22:00 EST
On Mon, 11 Dec 2023, Robin Murphy wrote:
Calling arm_cmn_event_clear() before all DTC indices are allocated is
wrong, and can lead to arm_cmn_event_add() erroneously clearing live
counters from full DTCs where allocation fails. Since the DTC counters
are only updated by arm_cmn_init_counter() after all DTC and DTM
allocations succeed, nothing actually needs cleaning up in this case
anyway, and it should just return directly as it did before.
Fixes: 7633ec2c262f ("perf/arm-cmn: Rework DTC counters (again)")
Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
That's a good catch.
Reviewed-by: Ilkka Koskinen <ilkka@xxxxxxxxxxxxxxxxxxxxxx>
Cheers, Ilkka
---
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 86d970e74129..c584165b13ba 100644
--- a/drivers/perf/arm-cmn.c
+++ b/drivers/perf/arm-cmn.c
@@ -1816,7 +1816,7 @@ static int arm_cmn_event_add(struct perf_event *event, int flags)
idx = 0;
while (cmn->dtc[j].counters[idx])
if (++idx == CMN_DT_NUM_COUNTERS)
- goto free_dtms;
+ return -ENOSPC;
}
hw->dtc_idx[j] = idx;
}
--
2.39.2.101.g768bb238c484.dirty