diff options
Diffstat (limited to 'kernel/events/core.c')
| -rw-r--r-- | kernel/events/core.c | 51 |
1 files changed, 36 insertions, 15 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 1f1b8cdaca2d..4d2c32f98482 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -926,11 +926,6 @@ static inline int is_cgroup_event(struct perf_event *event) return 0; } -static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event) -{ - return 0; -} - static inline void update_cgrp_time_from_event(struct perf_event *event) { } @@ -5722,9 +5717,6 @@ static void perf_output_read_one(struct perf_output_handle *handle, __output_copy(handle, values, n * sizeof(u64)); } -/* - * XXX PERF_FORMAT_GROUP vs inherited events seems difficult. - */ static void perf_output_read_group(struct perf_output_handle *handle, struct perf_event *event, u64 enabled, u64 running) @@ -5769,6 +5761,13 @@ static void perf_output_read_group(struct perf_output_handle *handle, #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ PERF_FORMAT_TOTAL_TIME_RUNNING) +/* + * XXX PERF_SAMPLE_READ vs inherited events seems difficult. + * + * The problem is that its both hard and excessively expensive to iterate the + * child list, not to mention that its impossible to IPI the children running + * on another CPU, from interrupt/NMI context. + */ static void perf_output_read(struct perf_output_handle *handle, struct perf_event *event) { @@ -7309,6 +7308,21 @@ int perf_event_account_interrupt(struct perf_event *event) return __perf_event_account_interrupt(event, 1); } +static bool sample_is_allowed(struct perf_event *event, struct pt_regs *regs) +{ + /* + * Due to interrupt latency (AKA "skid"), we may enter the + * kernel before taking an overflow, even if the PMU is only + * counting user events. + * To avoid leaking information to userspace, we must always + * reject kernel samples when exclude_kernel is set. + */ + if (event->attr.exclude_kernel && !user_mode(regs)) + return false; + + return true; +} + /* * Generic event overflow handling, sampling. */ @@ -7330,6 +7344,12 @@ static int __perf_event_overflow(struct perf_event *event, ret = __perf_event_account_interrupt(event, throttle); /* + * For security, drop the skid kernel samples if necessary. + */ + if (!sample_is_allowed(event, regs)) + return ret; + + /* * XXX event_limit might not quite work as expected on inherited * events */ @@ -9165,7 +9185,7 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) static struct pmu *perf_init_event(struct perf_event *event) { - struct pmu *pmu = NULL; + struct pmu *pmu; int idx; int ret; @@ -9434,9 +9454,10 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, local64_set(&hwc->period_left, hwc->sample_period); /* - * we currently do not support PERF_FORMAT_GROUP on inherited events + * We currently do not support PERF_SAMPLE_READ on inherited events. + * See perf_output_read(). */ - if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) + if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ)) goto err_ns; if (!has_branch_stack(event)) @@ -9449,9 +9470,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, } pmu = perf_init_event(event); - if (!pmu) - goto err_ns; - else if (IS_ERR(pmu)) { + if (IS_ERR(pmu)) { err = PTR_ERR(pmu); goto err_ns; } @@ -9464,8 +9483,10 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, event->addr_filters_offs = kcalloc(pmu->nr_addr_filters, sizeof(unsigned long), GFP_KERNEL); - if (!event->addr_filters_offs) + if (!event->addr_filters_offs) { + err = -ENOMEM; goto err_per_task; + } /* force hw sync on the address filters */ event->addr_filters_gen = 1; |
