On 3/27/2024 9:11 PM, Jim Mattson wrote:
On Tue, Jan 2, 2024 at 7:09 PM Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx> wrote:Current PMU code deosn't check whether PMU fixed counter number is larger than pre-defined fixed events. If so, it would cause memory access out of range. So add assert to warn this invalid case. Signed-off-by: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx> --- x86/pmu.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/x86/pmu.c b/x86/pmu.c index a13b8a8398c6..a42fff8d8b36 100644 --- a/x86/pmu.c +++ b/x86/pmu.c @@ -111,8 +111,12 @@ static struct pmu_event* get_counter_event(pmu_counter_t *cnt) for (i = 0; i < gp_events_size; i++) if (gp_events[i].unit_sel == (cnt->config & 0xffff)) return &gp_events[i]; - } else - return &fixed_events[cnt->ctr - MSR_CORE_PERF_FIXED_CTR0]; + } else { + int idx = cnt->ctr - MSR_CORE_PERF_FIXED_CTR0; + + assert(idx < ARRAY_SIZE(fixed_events)); + return &fixed_events[idx]; + } return (void*)0; } @@ -245,6 +249,7 @@ static void check_fixed_counters(void) }; int i; + assert(pmu.nr_fixed_counters <= ARRAY_SIZE(fixed_events)); for (i = 0; i < pmu.nr_fixed_counters; i++) { cnt.ctr = fixed_events[i].unit_sel; measure_one(&cnt); @@ -266,6 +271,7 @@ static void check_counters_many(void) gp_events[i % gp_events_size].unit_sel; n++; } + assert(pmu.nr_fixed_counters <= ARRAY_SIZE(fixed_events));Can we assert this just once, in main()?
sure. would do.
for (i = 0; i < pmu.nr_fixed_counters; i++) { cnt[n].ctr = fixed_events[i].unit_sel; cnt[n].config = EVNTSEL_OS | EVNTSEL_USR; -- 2.34.1
