[PATCH v2 1/2] perf: RISC-V: fix access beyond allocated array

[Atish Patra]

On Fri, Jun 24, 2022 at 6:59 AM Sergey Matyukevich <geomatsi at gmail.com> wrote:
>
> From: Sergey Matyukevich <sergey.matyukevich at syntacore.com>
>
> The root cause could be related to the interpretation of the number of
> counters reported by SBI firmware. For instance, if we assume that unused
> timer counter with index 1 is not reported, then the range is correct
> and larger array needs to be allocated.
>
> This is not the case though since SBI firmware is supposed to report the
> total number of firmware and hardware counters including special or
> unused ones like the timer counter. So just fix the range in for-loop.
>
> Signed-off-by: Sergey Matyukevich <sergey.matyukevich at syntacore.com>
> ---
>  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 dca3537a8dcc..a5d25b51beac 100644
> --- a/drivers/perf/riscv_pmu_sbi.c
> +++ b/drivers/perf/riscv_pmu_sbi.c
> @@ -457,7 +457,7 @@ 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 */
> --
> 2.36.1
>
LGTM.

Reviewed-by: Atish Patra <atishp at rivosinc.com>

-- 
Regards,
Atish