From c2449674a485d7d215efd6e7c966c2f08200134c Mon Sep 17 00:00:00 2001 From: Sergey Matyukevich Date: Tue, 30 Aug 2022 18:53:04 +0300 Subject: [PATCH] perf: RISC-V: fix access beyond allocated array SBI firmware should report total number of firmware and hardware counters including unused ones or special ones. In this case the kernel doesn't need to make any assumptions about gaps in reported counters, e.g. excluded timer counter. That was fixed in OpenSBI v1.1 by commit 3f66465fb6bf ("lib: pmu: allow to use the highest available counter"). This kernel patch has no effect if SBI firmware behaves correctly. However it eliminates access beyond the allocated pmu_ctr_list if the kernel is used with OpenSBI older than v1.1. Fixes: b6639251359e ("RISC-V: Add perf platform driver based on SBI PMU extension") Signed-off-by: Sergey Matyukevich Reviewed-by: Atish Patra Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220830155306.301714-2-geomatsi@gmail.com Signed-off-by: Palmer Dabbelt --- drivers/perf/riscv_pmu_sbi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c index 6f6681bbfd36d..8de4ca2fef210 100644 --- a/drivers/perf/riscv_pmu_sbi.c +++ b/drivers/perf/riscv_pmu_sbi.c @@ -473,7 +473,7 @@ static int pmu_sbi_get_ctrinfo(int nctr) if (!pmu_ctr_list) return -ENOMEM; - for (i = 0; i <= nctr; i++) { + for (i = 0; i < nctr; i++) { ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_GET_INFO, i, 0, 0, 0, 0, 0); if (ret.error) /* The logical counter ids are not expected to be contiguous */ -- 2.39.5