Messages in this thread Patch in this message | | | Date | Fri, 1 Feb 2019 08:43:53 +0100 | From | Jiri Olsa <> | Subject | Re: System crash with perf_fuzzer (kernel: 5.0.0-rc3) |
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On Thu, Jan 31, 2019 at 09:27:11AM +0100, Jiri Olsa wrote: > On Wed, Jan 30, 2019 at 07:36:48PM +0100, Jiri Olsa wrote: > > SNIP > > > diff --git a/kernel/events/core.c b/kernel/events/core.c > > index 280a72b3a553..22ec63a0782e 100644 > > --- a/kernel/events/core.c > > +++ b/kernel/events/core.c > > @@ -4969,6 +4969,26 @@ static void __perf_event_period(struct perf_event *event, > > } > > } > > > > +static int check_period(struct perf_event *event, u64 value) > > +{ > > + u64 sample_period_attr = event->attr.sample_period; > > + u64 sample_period_hw = event->hw.sample_period; > > + int ret; > > + > > + if (event->attr.freq) { > > + event->attr.sample_freq = value; > > + } else { > > + event->attr.sample_period = value; > > + event->hw.sample_period = value; > > + } > > hm, I think we need to check the period without changing the event, > because we don't disable pmu, so it might get picked up by bts code > > will check
with attached patch I did not trigger the fuzzer crash for over a day now, could you guys try?
thanks, jirka
--- arch/x86/events/core.c | 14 ++++++++++++++ arch/x86/events/intel/core.c | 9 +++++++++ arch/x86/events/perf_event.h | 16 ++++++++++++++-- include/linux/perf_event.h | 5 +++++ kernel/events/core.c | 16 ++++++++++++++++ 5 files changed, 58 insertions(+), 2 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 374a19712e20..b684f0294f35 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2278,6 +2278,19 @@ void perf_check_microcode(void) x86_pmu.check_microcode(); } +static int x86_pmu_check_period(struct perf_event *event, u64 value) +{ + if (x86_pmu.check_period && x86_pmu.check_period(event, value)) + return -EINVAL; + + if (value && x86_pmu.limit_period) { + if (x86_pmu.limit_period(event, value) > value) + return -EINVAL; + } + + return 0; +} + static struct pmu pmu = { .pmu_enable = x86_pmu_enable, .pmu_disable = x86_pmu_disable, @@ -2302,6 +2315,7 @@ static struct pmu pmu = { .event_idx = x86_pmu_event_idx, .sched_task = x86_pmu_sched_task, .task_ctx_size = sizeof(struct x86_perf_task_context), + .check_period = x86_pmu_check_period, }; void arch_perf_update_userpage(struct perf_event *event, diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 8b4e3020aba2..a3fbbd33beef 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3586,6 +3586,11 @@ static void intel_pmu_sched_task(struct perf_event_context *ctx, intel_pmu_lbr_sched_task(ctx, sched_in); } +static int intel_pmu_check_period(struct perf_event *event, u64 value) +{ + return intel_pmu_has_bts_period(event, value) ? -EINVAL : 0; +} + PMU_FORMAT_ATTR(offcore_rsp, "config1:0-63"); PMU_FORMAT_ATTR(ldlat, "config1:0-15"); @@ -3665,6 +3670,8 @@ static __initconst const struct x86_pmu core_pmu = { .cpu_prepare = intel_pmu_cpu_prepare, .cpu_starting = intel_pmu_cpu_starting, .cpu_dying = intel_pmu_cpu_dying, + + .check_period = intel_pmu_check_period, }; static struct attribute *intel_pmu_attrs[]; @@ -3707,6 +3714,8 @@ static __initconst const struct x86_pmu intel_pmu = { .cpu_dying = intel_pmu_cpu_dying, .guest_get_msrs = intel_guest_get_msrs, .sched_task = intel_pmu_sched_task, + + .check_period = intel_pmu_check_period, }; static __init void intel_clovertown_quirk(void) diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index 78d7b7031bfc..d46fd6754d92 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -646,6 +646,11 @@ struct x86_pmu { * Intel host/guest support (KVM) */ struct perf_guest_switch_msr *(*guest_get_msrs)(int *nr); + + /* + * Check period value for PERF_EVENT_IOC_PERIOD ioctl. + */ + int (*check_period) (struct perf_event *event, u64 period); }; struct x86_perf_task_context { @@ -857,7 +862,7 @@ static inline int amd_pmu_init(void) #ifdef CONFIG_CPU_SUP_INTEL -static inline bool intel_pmu_has_bts(struct perf_event *event) +static inline bool intel_pmu_has_bts_period(struct perf_event *event, u64 period) { struct hw_perf_event *hwc = &event->hw; unsigned int hw_event, bts_event; @@ -868,7 +873,14 @@ static inline bool intel_pmu_has_bts(struct perf_event *event) hw_event = hwc->config & INTEL_ARCH_EVENT_MASK; bts_event = x86_pmu.event_map(PERF_COUNT_HW_BRANCH_INSTRUCTIONS); - return hw_event == bts_event && hwc->sample_period == 1; + return hw_event == bts_event && period == 1; +} + +static inline bool intel_pmu_has_bts(struct perf_event *event) +{ + struct hw_perf_event *hwc = &event->hw; + + return intel_pmu_has_bts_period(event, hwc->sample_period); } int intel_pmu_save_and_restart(struct perf_event *event); diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index f2f9f8592d42..0a7d4d6a3660 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -447,6 +447,11 @@ struct pmu { * Filter events for PMU-specific reasons. */ int (*filter_match) (struct perf_event *event); /* optional */ + + /* + * Check period value for PERF_EVENT_IOC_PERIOD ioctl. + */ + int (*check_period) (struct perf_event *event, u64 value); /* optional */ }; enum perf_addr_filter_action_t { diff --git a/kernel/events/core.c b/kernel/events/core.c index 214c434ddc1b..edd92dc556fb 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4969,6 +4969,11 @@ static void __perf_event_period(struct perf_event *event, } } +static int perf_event_check_period(struct perf_event *event, u64 value) +{ + return event->pmu->check_period(event, value); +} + static int perf_event_period(struct perf_event *event, u64 __user *arg) { u64 value; @@ -4985,6 +4990,9 @@ static int perf_event_period(struct perf_event *event, u64 __user *arg) if (event->attr.freq && value > sysctl_perf_event_sample_rate) return -EINVAL; + if (perf_event_check_period(event, value)) + return -EINVAL; + event_function_call(event, __perf_event_period, &value); return 0; @@ -9601,6 +9609,11 @@ static int perf_pmu_nop_int(struct pmu *pmu) return 0; } +static int perf_event_nop_int(struct perf_event *event, u64 value) +{ + return 0; +} + static DEFINE_PER_CPU(unsigned int, nop_txn_flags); static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags) @@ -9901,6 +9914,9 @@ int perf_pmu_register(struct pmu *pmu, const char *name, int type) pmu->pmu_disable = perf_pmu_nop_void; } + if (!pmu->check_period) + pmu->check_period = perf_event_nop_int; + if (!pmu->event_idx) pmu->event_idx = perf_event_idx_default; -- 2.17.2
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