4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yang Jihong <yangjihong1@xxxxxxxxxx> commit 6b959ba22d34ca793ffdb15b5715457c78e38b1a upstream. perf_output_read_group may respond to IPI request of other cores and invoke __perf_install_in_context function. As a result, hwc configuration is modified. causing inconsistency and unexpected consequences. Interrupts are not disabled when perf_output_read_group reads PMU counter. In this case, IPI request may be received from other cores. As a result, PMU configuration is modified and an error occurs when reading PMU counter: CPU0 CPU1 __se_sys_perf_event_open perf_install_in_context perf_output_read_group smp_call_function_single for_each_sibling_event(sub, leader) { generic_exec_single if ((sub != event) && remote_function (sub->state == PERF_EVENT_STATE_ACTIVE)) | <enter IPI handler: __perf_install_in_context> <----RAISE IPI-----+ __perf_install_in_context ctx_resched event_sched_out armpmu_del ... hwc->idx = -1; // event->hwc.idx is set to -1 ... <exit IPI> sub->pmu->read(sub); armpmu_read armv8pmu_read_counter armv8pmu_read_hw_counter int idx = event->hw.idx; // idx = -1 u64 val = armv8pmu_read_evcntr(idx); u32 counter = ARMV8_IDX_TO_COUNTER(idx); // invalid counter = 30 read_pmevcntrn(counter) // undefined instruction Signed-off-by: Yang Jihong <yangjihong1@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/20220902082918.179248-1-yangjihong1@xxxxxxxxxx Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/events/core.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6253,9 +6253,16 @@ static void perf_output_read_group(struc { struct perf_event *leader = event->group_leader, *sub; u64 read_format = event->attr.read_format; + unsigned long flags; u64 values[6]; int n = 0; + /* + * Disabling interrupts avoids all counter scheduling + * (context switches, timer based rotation and IPIs). + */ + local_irq_save(flags); + values[n++] = 1 + leader->nr_siblings; if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) @@ -6291,6 +6298,8 @@ static void perf_output_read_group(struc __output_copy(handle, values, n * sizeof(u64)); } + + local_irq_restore(flags); } #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\