6.6-stable review patch. If anyone has any objections, please let me know.
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From: Robin Murphy robin.murphy@arm.com
commit 1892fe103c3a20fced306c8dafa74f7f6d4ea0a3 upstream.
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@arm.com Reviewed-by: Ilkka Koskinen ilkka@os.amperecomputing.com Acked-by: Will Deacon will@kernel.org Link: https://lore.kernel.org/r/ed589c0d8e4130dc68b8ad1625226d28bdc185d4.170232284... Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/perf/arm-cmn.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/perf/arm-cmn.c +++ b/drivers/perf/arm-cmn.c @@ -1794,7 +1794,7 @@ static int arm_cmn_event_add(struct perf idx = 0; while (cmn->dtc[j].counters[idx]) if (++idx == CMN_DT_NUM_COUNTERS) - goto free_dtms; + return -ENOSPC; } hw->dtc_idx[j] = idx; }