From: "Suzuki K. Poulose" <suzuki.poul...@arm.com> Don't allow grouping hardware events from different PMUs (eg. CCI + CPU).
Fixes a crash triggered by perf_fuzzer on Linux-4.0-rc2, with CCI PMU turned on. The validate_event(), after certain checks, assumes that the given hardware pmu event belongs to armpmu, which may not be true always, with other hardware PMUs around (CCI, CCN). --- CPU: 0 PID: 1527 Comm: perf_fuzzer Not tainted 4.0.0-rc2 #57 Hardware name: ARM-Versatile Express task: bd8484c0 ti: be676000 task.ti: be676000 PC is at 0xbf1bbc90 LR is at validate_event+0x34/0x5c pc : [<bf1bbc90>] lr : [<80016060>] psr: 00000013 ... [<80016060>] (validate_event) from [<80016198>] (validate_group+0x28/0x90) [<80016198>] (validate_group) from [<80016398>] (armpmu_event_init+0x150/0x218) [<80016398>] (armpmu_event_init) from [<800882e4>] (perf_try_init_event+0x30/0x48) [<800882e4>] (perf_try_init_event) from [<8008f544>] (perf_init_event+0x5c/0xf4) [<8008f544>] (perf_init_event) from [<8008f8a8>] (perf_event_alloc+0x2cc/0x35c) [<8008f8a8>] (perf_event_alloc) from [<8009015c>] (SyS_perf_event_open+0x498/0xa70) [<8009015c>] (SyS_perf_event_open) from [<8000e420>] (ret_fast_syscall+0x0/0x34) Code: bf1be000 bf1bb380 802a2664 00000000 (00000002) ---[ end trace 01aff0ff00926a0a ]--- Also cleans up the code to use the arm_pmu only when we know that we are dealing with an arm pmu event. Cc: Will Deacon <will.dea...@arm.com> Cc: Mark Rutland <mark.rutl...@arm.com> Signed-off-by: Suzuki K. Poulose <suzuki.poul...@arm.com> --- arch/arm/kernel/perf_event.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c index 557e128..4a86a01 100644 --- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -259,20 +259,29 @@ out: } static int -validate_event(struct pmu_hw_events *hw_events, - struct perf_event *event) +validate_event(struct pmu *pmu, struct pmu_hw_events *hw_events, + struct perf_event *event) { - struct arm_pmu *armpmu = to_arm_pmu(event->pmu); + struct arm_pmu *armpmu; if (is_software_event(event)) return 1; + /* + * Reject groups spanning multiple HW PMUs (e.g. CPU + CCI). The + * core perf code won't check that the pmu->ctx == leader->ctx + * until after pmu->event_init(event). + */ + if (event->pmu != pmu) + return 0; + if (event->state < PERF_EVENT_STATE_OFF) return 1; if (event->state == PERF_EVENT_STATE_OFF && !event->attr.enable_on_exec) return 1; + armpmu = to_arm_pmu(event->pmu); return armpmu->get_event_idx(hw_events, event) >= 0; } @@ -288,15 +297,15 @@ validate_group(struct perf_event *event) */ memset(&fake_pmu.used_mask, 0, sizeof(fake_pmu.used_mask)); - if (!validate_event(&fake_pmu, leader)) + if (!validate_event(event->pmu, &fake_pmu, leader)) return -EINVAL; list_for_each_entry(sibling, &leader->sibling_list, group_entry) { - if (!validate_event(&fake_pmu, sibling)) + if (!validate_event(event->pmu, &fake_pmu, sibling)) return -EINVAL; } - if (!validate_event(&fake_pmu, event)) + if (!validate_event(event->pmu, &fake_pmu, event)) return -EINVAL; return 0; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/