From e321d02db87af7840da29ef833a2a71fc0eab198 Mon Sep 17 00:00:00 2001 From: Kan Liang Date: Tue, 28 May 2019 15:08:30 -0700 Subject: [PATCH] perf/x86: Disable extended registers for non-supported PMUs The perf fuzzer caused Skylake machine to crash: [ 9680.085831] Call Trace: [ 9680.088301] [ 9680.090363] perf_output_sample_regs+0x43/0xa0 [ 9680.094928] perf_output_sample+0x3aa/0x7a0 [ 9680.099181] perf_event_output_forward+0x53/0x80 [ 9680.103917] __perf_event_overflow+0x52/0xf0 [ 9680.108266] ? perf_trace_run_bpf_submit+0xc0/0xc0 [ 9680.113108] perf_swevent_hrtimer+0xe2/0x150 [ 9680.117475] ? check_preempt_wakeup+0x181/0x230 [ 9680.122091] ? check_preempt_curr+0x62/0x90 [ 9680.126361] ? ttwu_do_wakeup+0x19/0x140 [ 9680.130355] ? try_to_wake_up+0x54/0x460 [ 9680.134366] ? reweight_entity+0x15b/0x1a0 [ 9680.138559] ? __queue_work+0x103/0x3f0 [ 9680.142472] ? update_dl_rq_load_avg+0x1cd/0x270 [ 9680.147194] ? timerqueue_del+0x1e/0x40 [ 9680.151092] ? __remove_hrtimer+0x35/0x70 [ 9680.155191] __hrtimer_run_queues+0x100/0x280 [ 9680.159658] hrtimer_interrupt+0x100/0x220 [ 9680.163835] smp_apic_timer_interrupt+0x6a/0x140 [ 9680.168555] apic_timer_interrupt+0xf/0x20 [ 9680.172756] The XMM registers can only be collected by PEBS hardware events on the platforms with PEBS baseline support, e.g. Icelake, not software/probe events. Add capabilities flag PERF_PMU_CAP_EXTENDED_REGS to indicate the PMU which support extended registers. For X86, the extended registers are XMM registers. Add has_extended_regs() to check if extended registers are applied. The generic code define the mask of extended registers as 0 if arch headers haven't overridden it. Originally-by: Peter Zijlstra (Intel) Reported-by: Vince Weaver Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Fixes: 878068ea270e ("perf/x86: Support outputting XMM registers") Link: https://lkml.kernel.org/r/1559081314-9714-1-git-send-email-kan.liang@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/events/intel/ds.c | 1 + arch/x86/include/uapi/asm/perf_regs.h | 3 +++ include/linux/perf_event.h | 1 + include/linux/perf_regs.h | 8 ++++++++ kernel/events/core.c | 18 ++++++++++++++---- 5 files changed, 27 insertions(+), 4 deletions(-) diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c index 7acc526b4ad2..6cb38ab02c8a 100644 --- a/arch/x86/events/intel/ds.c +++ b/arch/x86/events/intel/ds.c @@ -2020,6 +2020,7 @@ void __init intel_ds_init(void) PERF_SAMPLE_TIME; x86_pmu.flags |= PMU_FL_PEBS_ALL; pebs_qual = "-baseline"; + x86_get_pmu()->capabilities |= PERF_PMU_CAP_EXTENDED_REGS; } else { /* Only basic record supported */ x86_pmu.pebs_no_xmm_regs = 1; diff --git a/arch/x86/include/uapi/asm/perf_regs.h b/arch/x86/include/uapi/asm/perf_regs.h index ac67bbea10ca..7c9d2bb3833b 100644 --- a/arch/x86/include/uapi/asm/perf_regs.h +++ b/arch/x86/include/uapi/asm/perf_regs.h @@ -52,4 +52,7 @@ enum perf_event_x86_regs { /* These include both GPRs and XMMX registers */ PERF_REG_X86_XMM_MAX = PERF_REG_X86_XMM15 + 2, }; + +#define PERF_REG_EXTENDED_MASK (~((1ULL << PERF_REG_X86_XMM0) - 1)) + #endif /* _ASM_X86_PERF_REGS_H */ diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 0ab99c7b652d..2bca72f3028b 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -241,6 +241,7 @@ struct perf_event; #define PERF_PMU_CAP_NO_INTERRUPT 0x01 #define PERF_PMU_CAP_NO_NMI 0x02 #define PERF_PMU_CAP_AUX_NO_SG 0x04 +#define PERF_PMU_CAP_EXTENDED_REGS 0x08 #define PERF_PMU_CAP_EXCLUSIVE 0x10 #define PERF_PMU_CAP_ITRACE 0x20 #define PERF_PMU_CAP_HETEROGENEOUS_CPUS 0x40 diff --git a/include/linux/perf_regs.h b/include/linux/perf_regs.h index 476747456bca..2d12e97d5e7b 100644 --- a/include/linux/perf_regs.h +++ b/include/linux/perf_regs.h @@ -11,6 +11,11 @@ struct perf_regs { #ifdef CONFIG_HAVE_PERF_REGS #include + +#ifndef PERF_REG_EXTENDED_MASK +#define PERF_REG_EXTENDED_MASK 0 +#endif + u64 perf_reg_value(struct pt_regs *regs, int idx); int perf_reg_validate(u64 mask); u64 perf_reg_abi(struct task_struct *task); @@ -18,6 +23,9 @@ void perf_get_regs_user(struct perf_regs *regs_user, struct pt_regs *regs, struct pt_regs *regs_user_copy); #else + +#define PERF_REG_EXTENDED_MASK 0 + static inline u64 perf_reg_value(struct pt_regs *regs, int idx) { return 0; diff --git a/kernel/events/core.c b/kernel/events/core.c index 8d1c62df20a7..f85929ce13be 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10036,6 +10036,12 @@ void perf_pmu_unregister(struct pmu *pmu) } EXPORT_SYMBOL_GPL(perf_pmu_unregister); +static inline bool has_extended_regs(struct perf_event *event) +{ + return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) || + (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK); +} + static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) { struct perf_event_context *ctx = NULL; @@ -10067,12 +10073,16 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) perf_event_ctx_unlock(event->group_leader, ctx); if (!ret) { + if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) && + has_extended_regs(event)) + ret = -EOPNOTSUPP; + if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE && - event_has_any_exclude_flag(event)) { - if (event->destroy) - event->destroy(event); + event_has_any_exclude_flag(event)) ret = -EINVAL; - } + + if (ret && event->destroy) + event->destroy(event); } if (ret)