By Peter: git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git perf/pmu-unregister https://lore.kernel.org/all/20241022215210.GA31953@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ To be tested with additional igt tests Signed-off-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx> --- include/linux/idr.h | 17 + include/linux/perf_event.h | 35 ++- kernel/events/core.c | 620 +++++++++++++++++++++++++------------ 3 files changed, 455 insertions(+), 217 deletions(-) diff --git a/include/linux/idr.h b/include/linux/idr.h index da5f5fa4a3a6a..cd729be369b36 100644 --- a/include/linux/idr.h +++ b/include/linux/idr.h @@ -15,6 +15,7 @@ #include <linux/radix-tree.h> #include <linux/gfp.h> #include <linux/percpu.h> +#include <linux/cleanup.h> struct idr { struct radix_tree_root idr_rt; @@ -124,6 +125,22 @@ void *idr_get_next_ul(struct idr *, unsigned long *nextid); void *idr_replace(struct idr *, void *, unsigned long id); void idr_destroy(struct idr *); +struct __class_idr { + struct idr *idr; + int id; +}; + +#define idr_null ((struct __class_idr){ NULL, -1 }) +#define take_idr_id(id) __get_and_null(id, idr_null) + +DEFINE_CLASS(idr_alloc, struct __class_idr, + if (_T.id >= 0) idr_remove(_T.idr, _T.id), + ((struct __class_idr){ + .idr = idr, + .id = idr_alloc(idr, ptr, start, end, gfp), + }), + struct idr *idr, void *ptr, int start, int end, gfp_t gfp); + /** * idr_init_base() - Initialise an IDR. * @idr: IDR handle. diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index fb908843f2092..74c0eaeb96f6c 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -318,6 +318,9 @@ struct perf_output_handle; struct pmu { struct list_head entry; + spinlock_t events_lock; + struct list_head events; + struct module *module; struct device *dev; struct device *parent; @@ -336,8 +339,7 @@ struct pmu { */ unsigned int scope; - int __percpu *pmu_disable_count; - struct perf_cpu_pmu_context __percpu *cpu_pmu_context; + struct perf_cpu_pmu_context __percpu **cpu_pmu_context; atomic_t exclusive_cnt; /* < 0: cpu; > 0: tsk */ int task_ctx_nr; int hrtimer_interval_ms; @@ -612,9 +614,10 @@ struct perf_addr_filter_range { * enum perf_event_state - the states of an event: */ enum perf_event_state { - PERF_EVENT_STATE_DEAD = -4, - PERF_EVENT_STATE_EXIT = -3, - PERF_EVENT_STATE_ERROR = -2, + PERF_EVENT_STATE_DEAD = -5, + PERF_EVENT_STATE_REVOKED = -4, /* pmu gone, must not touch */ + PERF_EVENT_STATE_EXIT = -3, /* task died, still inherit */ + PERF_EVENT_STATE_ERROR = -2, /* scheduling error, can enable */ PERF_EVENT_STATE_OFF = -1, PERF_EVENT_STATE_INACTIVE = 0, PERF_EVENT_STATE_ACTIVE = 1, @@ -652,13 +655,15 @@ struct swevent_hlist { struct rcu_head rcu_head; }; -#define PERF_ATTACH_CONTEXT 0x01 -#define PERF_ATTACH_GROUP 0x02 -#define PERF_ATTACH_TASK 0x04 -#define PERF_ATTACH_TASK_DATA 0x08 -#define PERF_ATTACH_ITRACE 0x10 -#define PERF_ATTACH_SCHED_CB 0x20 -#define PERF_ATTACH_CHILD 0x40 +#define PERF_ATTACH_CONTEXT 0x0001 +#define PERF_ATTACH_GROUP 0x0002 +#define PERF_ATTACH_TASK 0x0004 +#define PERF_ATTACH_TASK_DATA 0x0008 +#define PERF_ATTACH_ITRACE 0x0010 +#define PERF_ATTACH_SCHED_CB 0x0020 +#define PERF_ATTACH_CHILD 0x0040 +#define PERF_ATTACH_EXCLUSIVE 0x0080 +#define PERF_ATTACH_CALLCHAIN 0x0100 struct bpf_prog; struct perf_cgroup; @@ -853,6 +858,7 @@ struct perf_event { void *security; #endif struct list_head sb_list; + struct list_head pmu_list; /* * Certain events gets forwarded to another pmu internally by over- @@ -900,7 +906,7 @@ struct perf_event_pmu_context { struct list_head pinned_active; struct list_head flexible_active; - /* Used to avoid freeing per-cpu perf_event_pmu_context */ + /* Used to identify the per-cpu perf_event_pmu_context */ unsigned int embedded : 1; unsigned int nr_events; @@ -1008,6 +1014,7 @@ struct perf_cpu_pmu_context { int active_oncpu; int exclusive; + int pmu_disable_count; raw_spinlock_t hrtimer_lock; struct hrtimer hrtimer; @@ -1103,7 +1110,7 @@ extern void perf_aux_output_flag(struct perf_output_handle *handle, u64 flags); extern void perf_event_itrace_started(struct perf_event *event); extern int perf_pmu_register(struct pmu *pmu, const char *name, int type); -extern void perf_pmu_unregister(struct pmu *pmu); +extern int perf_pmu_unregister(struct pmu *pmu); extern void __perf_event_task_sched_in(struct task_struct *prev, struct task_struct *task); diff --git a/kernel/events/core.c b/kernel/events/core.c index cea06cff258ed..0cdc7c8af1913 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1178,21 +1178,22 @@ static int perf_mux_hrtimer_restart_ipi(void *arg) void perf_pmu_disable(struct pmu *pmu) { - int *count = this_cpu_ptr(pmu->pmu_disable_count); + int *count = &(*this_cpu_ptr(pmu->cpu_pmu_context))->pmu_disable_count; if (!(*count)++) pmu->pmu_disable(pmu); } void perf_pmu_enable(struct pmu *pmu) { - int *count = this_cpu_ptr(pmu->pmu_disable_count); + int *count = &(*this_cpu_ptr(pmu->cpu_pmu_context))->pmu_disable_count; if (!--(*count)) pmu->pmu_enable(pmu); } static void perf_assert_pmu_disabled(struct pmu *pmu) { - WARN_ON_ONCE(*this_cpu_ptr(pmu->pmu_disable_count) == 0); + int *count = &(*this_cpu_ptr(pmu->cpu_pmu_context))->pmu_disable_count; + WARN_ON_ONCE(*count == 0); } static void get_ctx(struct perf_event_context *ctx) @@ -2303,7 +2304,7 @@ static void event_sched_out(struct perf_event *event, struct perf_event_context *ctx) { struct perf_event_pmu_context *epc = event->pmu_ctx; - struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context); + struct perf_cpu_pmu_context *cpc = *this_cpu_ptr(epc->pmu->cpu_pmu_context); enum perf_event_state state = PERF_EVENT_STATE_INACTIVE; // XXX cpc serialization, probably per-cpu IRQ disabled @@ -2406,7 +2407,9 @@ ctx_time_update_event(struct perf_event_context *ctx, struct perf_event *event) #define DETACH_GROUP 0x01UL #define DETACH_CHILD 0x02UL -#define DETACH_DEAD 0x04UL +#define DETACH_EXIT 0x04UL +#define DETACH_REVOKE 0x08UL +#define DETACH_DEAD 0x10UL /* * Cross CPU call to remove a performance event @@ -2421,6 +2424,7 @@ __perf_remove_from_context(struct perf_event *event, void *info) { struct perf_event_pmu_context *pmu_ctx = event->pmu_ctx; + enum perf_event_state state = PERF_EVENT_STATE_OFF; unsigned long flags = (unsigned long)info; ctx_time_update(cpuctx, ctx); @@ -2429,16 +2433,22 @@ __perf_remove_from_context(struct perf_event *event, * Ensure event_sched_out() switches to OFF, at the very least * this avoids raising perf_pending_task() at this time. */ - if (flags & DETACH_DEAD) + if (flags & DETACH_EXIT) + state = PERF_EVENT_STATE_EXIT; + if (flags & DETACH_REVOKE) + state = PERF_EVENT_STATE_REVOKED; + if (flags & DETACH_DEAD) { event->pending_disable = 1; + state = PERF_EVENT_STATE_DEAD; + } event_sched_out(event, ctx); if (flags & DETACH_GROUP) perf_group_detach(event); if (flags & DETACH_CHILD) perf_child_detach(event); list_del_event(event, ctx); - if (flags & DETACH_DEAD) - event->state = PERF_EVENT_STATE_DEAD; + + event->state = state; if (!pmu_ctx->nr_events) { pmu_ctx->rotate_necessary = 0; @@ -2446,7 +2456,7 @@ __perf_remove_from_context(struct perf_event *event, if (ctx->task && ctx->is_active) { struct perf_cpu_pmu_context *cpc; - cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context); + cpc = *this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context); WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx); cpc->task_epc = NULL; } @@ -2584,7 +2594,7 @@ static int event_sched_in(struct perf_event *event, struct perf_event_context *ctx) { struct perf_event_pmu_context *epc = event->pmu_ctx; - struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context); + struct perf_cpu_pmu_context *cpc = *this_cpu_ptr(epc->pmu->cpu_pmu_context); int ret = 0; WARN_ON_ONCE(event->ctx != ctx); @@ -2691,7 +2701,7 @@ group_sched_in(struct perf_event *group_event, struct perf_event_context *ctx) static int group_can_go_on(struct perf_event *event, int can_add_hw) { struct perf_event_pmu_context *epc = event->pmu_ctx; - struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context); + struct perf_cpu_pmu_context *cpc = *this_cpu_ptr(epc->pmu->cpu_pmu_context); /* * Groups consisting entirely of software events can always go on. @@ -3316,7 +3326,7 @@ static void __pmu_ctx_sched_out(struct perf_event_pmu_context *pmu_ctx, if (ctx->task && !(ctx->is_active & EVENT_ALL)) { struct perf_cpu_pmu_context *cpc; - cpc = this_cpu_ptr(pmu->cpu_pmu_context); + cpc = *this_cpu_ptr(pmu->cpu_pmu_context); WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx); cpc->task_epc = NULL; } @@ -3564,7 +3574,7 @@ static void perf_ctx_sched_task_cb(struct perf_event_context *ctx, bool sched_in struct perf_cpu_pmu_context *cpc; list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) { - cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context); + cpc = *this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context); if (cpc->sched_cb_usage && pmu_ctx->pmu->sched_task) pmu_ctx->pmu->sched_task(pmu_ctx, sched_in); @@ -3673,7 +3683,7 @@ static DEFINE_PER_CPU(int, perf_sched_cb_usages); void perf_sched_cb_dec(struct pmu *pmu) { - struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context); + struct perf_cpu_pmu_context *cpc = *this_cpu_ptr(pmu->cpu_pmu_context); this_cpu_dec(perf_sched_cb_usages); barrier(); @@ -3685,7 +3695,7 @@ void perf_sched_cb_dec(struct pmu *pmu) void perf_sched_cb_inc(struct pmu *pmu) { - struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context); + struct perf_cpu_pmu_context *cpc = *this_cpu_ptr(pmu->cpu_pmu_context); if (!cpc->sched_cb_usage++) list_add(&cpc->sched_cb_entry, this_cpu_ptr(&sched_cb_list)); @@ -3809,7 +3819,7 @@ static void __link_epc(struct perf_event_pmu_context *pmu_ctx) if (!pmu_ctx->ctx->task) return; - cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context); + cpc = *this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context); WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx); cpc->task_epc = pmu_ctx; } @@ -3941,7 +3951,7 @@ static int merge_sched_in(struct perf_event *event, void *data) struct perf_cpu_pmu_context *cpc; event->pmu_ctx->rotate_necessary = 1; - cpc = this_cpu_ptr(event->pmu_ctx->pmu->cpu_pmu_context); + cpc = *this_cpu_ptr(event->pmu_ctx->pmu->cpu_pmu_context); perf_mux_hrtimer_restart(cpc); group_update_userpage(event); } @@ -4508,7 +4518,8 @@ static void perf_event_enable_on_exec(struct perf_event_context *ctx) static void perf_remove_from_owner(struct perf_event *event); static void perf_event_exit_event(struct perf_event *event, - struct perf_event_context *ctx); + struct perf_event_context *ctx, + bool revoke); /* * Removes all events from the current task that have been marked @@ -4535,7 +4546,7 @@ static void perf_event_remove_on_exec(struct perf_event_context *ctx) modified = true; - perf_event_exit_event(event, ctx); + perf_event_exit_event(event, ctx, false); } raw_spin_lock_irqsave(&ctx->lock, flags); @@ -4968,11 +4979,14 @@ find_get_pmu_context(struct pmu *pmu, struct perf_event_context *ctx, */ struct perf_cpu_pmu_context *cpc; - cpc = per_cpu_ptr(pmu->cpu_pmu_context, event->cpu); + cpc = *per_cpu_ptr(pmu->cpu_pmu_context, event->cpu); epc = &cpc->epc; raw_spin_lock_irq(&ctx->lock); if (!epc->ctx) { - atomic_set(&epc->refcount, 1); + /* + * One extra reference for the pmu; see perf_pmu_free(). + */ + atomic_set(&epc->refcount, 2); epc->embedded = 1; list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list); epc->ctx = ctx; @@ -5041,6 +5055,15 @@ static void get_pmu_ctx(struct perf_event_pmu_context *epc) WARN_ON_ONCE(!atomic_inc_not_zero(&epc->refcount)); } +static void free_cpc_rcu(struct rcu_head *head) +{ + struct perf_cpu_pmu_context *cpc = + container_of(head, typeof(*cpc), epc.rcu_head); + + kfree(cpc->epc.task_ctx_data); + kfree(cpc); +} + static void free_epc_rcu(struct rcu_head *head) { struct perf_event_pmu_context *epc = container_of(head, typeof(*epc), rcu_head); @@ -5075,8 +5098,10 @@ static void put_pmu_ctx(struct perf_event_pmu_context *epc) raw_spin_unlock_irqrestore(&ctx->lock, flags); - if (epc->embedded) + if (epc->embedded) { + call_rcu(&epc->rcu_head, free_cpc_rcu); return; + } call_rcu(&epc->rcu_head, free_epc_rcu); } @@ -5121,6 +5146,7 @@ static bool is_sb_event(struct perf_event *event) attr->context_switch || attr->text_poke || attr->bpf_event) return true; + return false; } @@ -5246,6 +5272,8 @@ static int exclusive_event_init(struct perf_event *event) return -EBUSY; } + event->attach_state |= PERF_ATTACH_EXCLUSIVE; + return 0; } @@ -5253,14 +5281,13 @@ static void exclusive_event_destroy(struct perf_event *event) { struct pmu *pmu = event->pmu; - if (!is_exclusive_pmu(pmu)) - return; - /* see comment in exclusive_event_init() */ if (event->attach_state & PERF_ATTACH_TASK) atomic_dec(&pmu->exclusive_cnt); else atomic_inc(&pmu->exclusive_cnt); + + event->attach_state &= ~PERF_ATTACH_EXCLUSIVE; } static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2) @@ -5292,8 +5319,7 @@ static bool exclusive_event_installable(struct perf_event *event, return true; } -static void perf_addr_filters_splice(struct perf_event *event, - struct list_head *head); +static void perf_free_addr_filters(struct perf_event *event); static void perf_pending_task_sync(struct perf_event *event) { @@ -5319,40 +5345,22 @@ static void perf_pending_task_sync(struct perf_event *event) rcuwait_wait_event(&event->pending_work_wait, !event->pending_work, TASK_UNINTERRUPTIBLE); } -static void _free_event(struct perf_event *event) +/* vs perf_event_alloc() error */ +static void __free_event(struct perf_event *event) { - irq_work_sync(&event->pending_irq); - irq_work_sync(&event->pending_disable_irq); - perf_pending_task_sync(event); + struct pmu *pmu = event->pmu; - unaccount_event(event); + if (event->attach_state & PERF_ATTACH_CALLCHAIN) + put_callchain_buffers(); - security_perf_event_free(event); + kfree(event->addr_filter_ranges); - if (event->rb) { - /* - * Can happen when we close an event with re-directed output. - * - * Since we have a 0 refcount, perf_mmap_close() will skip - * over us; possibly making our ring_buffer_put() the last. - */ - mutex_lock(&event->mmap_mutex); - ring_buffer_attach(event, NULL); - mutex_unlock(&event->mmap_mutex); - } + if (event->attach_state & PERF_ATTACH_EXCLUSIVE) + exclusive_event_destroy(event); if (is_cgroup_event(event)) perf_detach_cgroup(event); - if (!event->parent) { - if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) - put_callchain_buffers(); - } - - perf_event_free_bpf_prog(event); - perf_addr_filters_splice(event, NULL); - kfree(event->addr_filter_ranges); - if (event->destroy) event->destroy(event); @@ -5363,22 +5371,67 @@ static void _free_event(struct perf_event *event) if (event->hw.target) put_task_struct(event->hw.target); - if (event->pmu_ctx) + if (event->pmu_ctx) { + /* + * put_pmu_ctx() needs an event->ctx reference, because of + * epc->ctx. + */ + WARN_ON_ONCE(!pmu); + WARN_ON_ONCE(!event->ctx); + WARN_ON_ONCE(event->pmu_ctx->ctx != event->ctx); put_pmu_ctx(event->pmu_ctx); + } /* - * perf_event_free_task() relies on put_ctx() being 'last', in particular - * all task references must be cleaned up. + * perf_event_free_task() relies on put_ctx() being 'last', in + * particular all task references must be cleaned up. */ if (event->ctx) put_ctx(event->ctx); - exclusive_event_destroy(event); - module_put(event->pmu->module); + if (pmu) { + module_put(pmu->module); + scoped_guard (spinlock, &pmu->events_lock) { + list_del(&event->pmu_list); + wake_up_var(pmu); + } + } call_rcu(&event->rcu_head, free_event_rcu); } +DEFINE_FREE(__free_event, struct perf_event *, if (_T) __free_event(_T)) + +/* vs perf_event_alloc() success */ +static void _free_event(struct perf_event *event) +{ + irq_work_sync(&event->pending_irq); + irq_work_sync(&event->pending_disable_irq); + perf_pending_task_sync(event); + + unaccount_event(event); + + security_perf_event_free(event); + + if (event->rb) { + WARN_ON_ONCE(!event->pmu); + /* + * Can happen when we close an event with re-directed output. + * + * Since we have a 0 refcount, perf_mmap_close() will skip + * over us; possibly making our ring_buffer_put() the last. + */ + mutex_lock(&event->mmap_mutex); + ring_buffer_attach(event, NULL); + mutex_unlock(&event->mmap_mutex); + } + + perf_event_free_bpf_prog(event); + perf_free_addr_filters(event); + + __free_event(event); +} + /* * Used to free events which have a known refcount of 1, such as in error paths * where the event isn't exposed yet and inherited events. @@ -5492,7 +5545,11 @@ int perf_event_release_kernel(struct perf_event *event) * Thus this guarantees that we will in fact observe and kill _ALL_ * child events. */ - perf_remove_from_context(event, DETACH_GROUP|DETACH_DEAD); + if (event->state > PERF_EVENT_STATE_REVOKED) { + perf_remove_from_context(event, DETACH_GROUP|DETACH_DEAD); + } else { + event->state = PERF_EVENT_STATE_DEAD; + } perf_event_ctx_unlock(event, ctx); @@ -5789,7 +5846,7 @@ __perf_read(struct perf_event *event, char __user *buf, * error state (i.e. because it was pinned but it couldn't be * scheduled on to the CPU at some point). */ - if (event->state == PERF_EVENT_STATE_ERROR) + if (event->state <= PERF_EVENT_STATE_ERROR) return 0; if (count < event->read_size) @@ -5843,8 +5900,14 @@ static __poll_t perf_poll(struct file *file, poll_table *wait) struct perf_buffer *rb; __poll_t events = EPOLLHUP; + if (event->state <= PERF_EVENT_STATE_REVOKED) + return EPOLLERR; + poll_wait(file, &event->waitq, wait); + if (event->state <= PERF_EVENT_STATE_REVOKED) + return EPOLLERR; + if (is_event_hup(event)) return events; @@ -6024,6 +6087,9 @@ static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned lon void (*func)(struct perf_event *); u32 flags = arg; + if (event->state <= PERF_EVENT_STATE_REVOKED) + return -ENODEV; + switch (cmd) { case PERF_EVENT_IOC_ENABLE: func = _perf_event_enable; @@ -6473,6 +6539,7 @@ static void perf_mmap_close(struct vm_area_struct *vma) unsigned long size = perf_data_size(rb); bool detach_rest = false; + /* FIXIES vs perf_pmu_unregister() */ if (event->pmu->event_unmapped) event->pmu->event_unmapped(event, vma->vm_mm); @@ -6581,9 +6648,8 @@ static const struct vm_operations_struct perf_mmap_vmops = { .page_mkwrite = perf_mmap_fault, }; -static int perf_mmap(struct file *file, struct vm_area_struct *vma) +static int _perf_mmap(struct perf_event *event, struct vm_area_struct *vma) { - struct perf_event *event = file->private_data; unsigned long user_locked, user_lock_limit; struct user_struct *user = current_user(); struct mutex *aux_mutex = NULL; @@ -6594,6 +6660,9 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) long user_extra = 0, extra = 0; int ret = 0, flags = 0; + if (event->state <= PERF_EVENT_STATE_REVOKED) + return -ENODEV; + /* * Don't allow mmap() of inherited per-task counters. This would * create a performance issue due to all children writing to the @@ -6605,10 +6674,6 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) if (!(vma->vm_flags & VM_SHARED)) return -EINVAL; - ret = security_perf_event_read(event); - if (ret) - return ret; - vma_size = vma->vm_end - vma->vm_start; if (vma->vm_pgoff == 0) { @@ -6805,12 +6870,32 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) return ret; } +static int perf_mmap(struct file *file, struct vm_area_struct *vma) +{ + struct perf_event *event = file->private_data; + struct perf_event_context *ctx; + int ret; + + ret = security_perf_event_read(event); + if (ret) + return ret; + + ctx = perf_event_ctx_lock(event); + ret = _perf_mmap(event, vma); + perf_event_ctx_unlock(event, ctx); + + return ret; +} + static int perf_fasync(int fd, struct file *filp, int on) { struct inode *inode = file_inode(filp); struct perf_event *event = filp->private_data; int retval; + if (event->state <= PERF_EVENT_STATE_REVOKED) + return -ENODEV; + inode_lock(inode); retval = fasync_helper(fd, filp, on, &event->fasync); inode_unlock(inode); @@ -10738,6 +10823,9 @@ int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, void perf_event_free_bpf_prog(struct perf_event *event) { + if (!event->prog) + return; + if (!perf_event_is_tracing(event)) { perf_event_free_bpf_handler(event); return; @@ -10836,6 +10924,17 @@ static void perf_addr_filters_splice(struct perf_event *event, free_filters_list(&list); } +static void perf_free_addr_filters(struct perf_event *event) +{ + /* + * Used during free paths, there is no concurrency. + */ + if (list_empty(&event->addr_filters.list)) + return; + + perf_addr_filters_splice(event, NULL); +} + /* * Scan through mm's vmas and see if one of them matches the * @filter; if so, adjust filter's address range. @@ -11512,11 +11611,6 @@ static int perf_event_idx_default(struct perf_event *event) return 0; } -static void free_pmu_context(struct pmu *pmu) -{ - free_percpu(pmu->cpu_pmu_context); -} - /* * Let userspace know that this PMU supports address range filtering: */ @@ -11579,7 +11673,7 @@ perf_event_mux_interval_ms_store(struct device *dev, cpus_read_lock(); for_each_online_cpu(cpu) { struct perf_cpu_pmu_context *cpc; - cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu); + cpc = *per_cpu_ptr(pmu->cpu_pmu_context, cpu); cpc->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer); cpu_function_call(cpu, perf_mux_hrtimer_restart_ipi, cpc); @@ -11728,56 +11822,100 @@ static int pmu_dev_alloc(struct pmu *pmu) static struct lock_class_key cpuctx_mutex; static struct lock_class_key cpuctx_lock; -int perf_pmu_register(struct pmu *pmu, const char *name, int type) +static bool idr_cmpxchg(struct idr *idr, unsigned long id, void *old, void *new) { - int cpu, ret, max = PERF_TYPE_MAX; + void *tmp, *val = idr_find(idr, id); - mutex_lock(&pmus_lock); - ret = -ENOMEM; - pmu->pmu_disable_count = alloc_percpu(int); - if (!pmu->pmu_disable_count) - goto unlock; + if (val != old) + return false; - pmu->type = -1; - if (WARN_ONCE(!name, "Can not register anonymous pmu.\n")) { - ret = -EINVAL; - goto free_pdc; + tmp = idr_replace(idr, new, id); + if (IS_ERR(tmp)) + return false; + + WARN_ON_ONCE(tmp != val); + return true; +} + +static void perf_pmu_free(struct pmu *pmu) +{ + if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) { + if (pmu->nr_addr_filters) + device_remove_file(pmu->dev, &dev_attr_nr_addr_filters); + device_del(pmu->dev); + put_device(pmu->dev); } - if (WARN_ONCE(pmu->scope >= PERF_PMU_MAX_SCOPE, "Can not register a pmu with an invalid scope.\n")) { - ret = -EINVAL; - goto free_pdc; + if (pmu->cpu_pmu_context) { + int cpu; + + for_each_possible_cpu(cpu) { + struct perf_cpu_pmu_context *cpc; + + cpc = *per_cpu_ptr(pmu->cpu_pmu_context, cpu); + if (!cpc) + continue; + if (cpc->epc.embedded) { + /* refcount managed */ + put_pmu_ctx(&cpc->epc); + continue; + } + kfree(cpc); + } + free_percpu(pmu->cpu_pmu_context); } +} + +DEFINE_FREE(pmu_unregister, struct pmu *, if (_T) perf_pmu_free(_T)) + +int perf_pmu_register(struct pmu *_pmu, const char *name, int type) +{ + int cpu, max = PERF_TYPE_MAX; + + struct pmu *pmu __free(pmu_unregister) = _pmu; + guard(mutex)(&pmus_lock); + + if (WARN_ONCE(!name, "Can not register anonymous pmu.\n")) + return -EINVAL; + + if (WARN_ONCE(pmu->scope >= PERF_PMU_MAX_SCOPE, + "Can not register a pmu with an invalid scope.\n")) + return -EINVAL; pmu->name = name; if (type >= 0) max = type; - ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL); - if (ret < 0) - goto free_pdc; + CLASS(idr_alloc, pmu_type)(&pmu_idr, NULL, max, 0, GFP_KERNEL); + if (pmu_type.id < 0) + return pmu_type.id; - WARN_ON(type >= 0 && ret != type); + WARN_ON(type >= 0 && pmu_type.id != type); - type = ret; - pmu->type = type; + pmu->type = pmu_type.id; + atomic_set(&pmu->exclusive_cnt, 0); if (pmu_bus_running && !pmu->dev) { - ret = pmu_dev_alloc(pmu); + int ret = pmu_dev_alloc(pmu); if (ret) - goto free_idr; + return ret; } - ret = -ENOMEM; - pmu->cpu_pmu_context = alloc_percpu(struct perf_cpu_pmu_context); + pmu->cpu_pmu_context = alloc_percpu(struct perf_cpu_pmu_context *); if (!pmu->cpu_pmu_context) - goto free_dev; + return -ENOMEM; for_each_possible_cpu(cpu) { - struct perf_cpu_pmu_context *cpc; + struct perf_cpu_pmu_context *cpc = + kmalloc_node(sizeof(struct perf_cpu_pmu_context), + GFP_KERNEL | __GFP_ZERO, + cpu_to_node(cpu)); - cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu); + if (!cpc) + return -ENOMEM; + + *per_cpu_ptr(pmu->cpu_pmu_context, cpu) = cpc; __perf_init_event_pmu_context(&cpc->epc, pmu); __perf_mux_hrtimer_init(cpc, cpu); } @@ -11810,33 +11948,115 @@ int perf_pmu_register(struct pmu *pmu, const char *name, int type) if (!pmu->event_idx) pmu->event_idx = perf_event_idx_default; + INIT_LIST_HEAD(&pmu->events); + spin_lock_init(&pmu->events_lock); + + /* + * Now that the PMU is complete, make it visible to perf_try_init_event(). + */ + if (!idr_cmpxchg(&pmu_idr, pmu->type, NULL, pmu)) + return -EINVAL; list_add_rcu(&pmu->entry, &pmus); - atomic_set(&pmu->exclusive_cnt, 0); - ret = 0; -unlock: - mutex_unlock(&pmus_lock); - return ret; + take_idr_id(pmu_type); + _pmu = no_free_ptr(pmu); // let it rip + return 0; +} +EXPORT_SYMBOL_GPL(perf_pmu_register); -free_dev: - if (pmu->dev && pmu->dev != PMU_NULL_DEV) { - device_del(pmu->dev); - put_device(pmu->dev); +static void __pmu_detach_event(struct pmu *pmu, struct perf_event *event, + struct perf_event_context *ctx) +{ + /* + * De-schedule the event and mark it REVOKED. + */ + perf_event_exit_event(event, ctx, true); + + /* + * All _free_event() bits that rely on event->pmu: + */ + scoped_guard (mutex, &event->mmap_mutex) { + WARN_ON_ONCE(pmu->event_unmapped); + ring_buffer_attach(event, NULL); + } + + perf_event_free_bpf_prog(event); + perf_free_addr_filters(event); + + if (event->destroy) { + event->destroy(event); + event->destroy = NULL; + } + + if (event->pmu_ctx) { + put_pmu_ctx(event->pmu_ctx); + event->pmu_ctx = NULL; } -free_idr: - idr_remove(&pmu_idr, pmu->type); + exclusive_event_destroy(event); + module_put(pmu->module); -free_pdc: - free_percpu(pmu->pmu_disable_count); - goto unlock; + event->pmu = NULL; /* force fault instead of UAF */ } -EXPORT_SYMBOL_GPL(perf_pmu_register); -void perf_pmu_unregister(struct pmu *pmu) +static void pmu_detach_event(struct pmu *pmu, struct perf_event *event) { - mutex_lock(&pmus_lock); - list_del_rcu(&pmu->entry); + struct perf_event_context *ctx; + + ctx = perf_event_ctx_lock(event); + __pmu_detach_event(pmu, event, ctx); + perf_event_ctx_unlock(event, ctx); + + scoped_guard (spinlock, &pmu->events_lock) + list_del(&event->pmu_list); +} + +static struct perf_event *pmu_get_event(struct pmu *pmu) +{ + struct perf_event *event; + + guard(spinlock)(&pmu->events_lock); + list_for_each_entry(event, &pmu->events, pmu_list) { + if (atomic_long_inc_not_zero(&event->refcount)) + return event; + } + + return NULL; +} + +static bool pmu_empty(struct pmu *pmu) +{ + guard(spinlock)(&pmu->events_lock); + return list_empty(&pmu->events); +} + +static void pmu_detach_events(struct pmu *pmu) +{ + struct perf_event *event; + + for (;;) { + event = pmu_get_event(pmu); + if (!event) + break; + + pmu_detach_event(pmu, event); + put_event(event); + } + + /* + * wait for pending _free_event()s + */ + wait_var_event(pmu, pmu_empty(pmu)); +} + +int perf_pmu_unregister(struct pmu *pmu) +{ + scoped_guard (mutex, &pmus_lock) { + if (!idr_cmpxchg(&pmu_idr, pmu->type, pmu, NULL)) + return -EINVAL; + + list_del_rcu(&pmu->entry); + } /* * We dereference the pmu list under both SRCU and regular RCU, so @@ -11845,16 +12065,31 @@ void perf_pmu_unregister(struct pmu *pmu) synchronize_srcu(&pmus_srcu); synchronize_rcu(); - free_percpu(pmu->pmu_disable_count); - idr_remove(&pmu_idr, pmu->type); - if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) { - if (pmu->nr_addr_filters) - device_remove_file(pmu->dev, &dev_attr_nr_addr_filters); - device_del(pmu->dev); - put_device(pmu->dev); + if (pmu->event_unmapped && !pmu_empty(pmu)) { + /* + * Can't force remove events when pmu::event_unmapped() + * is used in perf_mmap_close(). + */ + guard(mutex)(&pmus_lock); + idr_cmpxchg(&pmu_idr, pmu->type, NULL, pmu); + list_add_rcu(&pmu->entry, &pmus); + return -EBUSY; } - free_pmu_context(pmu); - mutex_unlock(&pmus_lock); + + scoped_guard (mutex, &pmus_lock) + idr_remove(&pmu_idr, pmu->type); + + /* + * PMU is removed from the pmus list, so no new events will + * be created, now take care of the existing ones. + */ + pmu_detach_events(pmu); + + /* + * PMU is unused, make it go away. + */ + perf_pmu_free(pmu); + return 0; } EXPORT_SYMBOL_GPL(perf_pmu_unregister); @@ -11923,8 +12158,10 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) event->destroy(event); } - if (ret) + if (ret) { + event->pmu = NULL; module_put(pmu->module); + } return ret; } @@ -11932,10 +12169,10 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) static struct pmu *perf_init_event(struct perf_event *event) { bool extended_type = false; - int idx, type, ret; struct pmu *pmu; + int type, ret; - idx = srcu_read_lock(&pmus_srcu); + guard(srcu)(&pmus_srcu); /* * Save original type before calling pmu->event_init() since certain @@ -11948,7 +12185,7 @@ static struct pmu *perf_init_event(struct perf_event *event) pmu = event->parent->pmu; ret = perf_try_init_event(pmu, event); if (!ret) - goto unlock; + return pmu; } /* @@ -11967,13 +12204,12 @@ static struct pmu *perf_init_event(struct perf_event *event) } again: - rcu_read_lock(); - pmu = idr_find(&pmu_idr, type); - rcu_read_unlock(); + scoped_guard (rcu) + pmu = idr_find(&pmu_idr, type); if (pmu) { if (event->attr.type != type && type != PERF_TYPE_RAW && !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE)) - goto fail; + return ERR_PTR(-ENOENT); ret = perf_try_init_event(pmu, event); if (ret == -ENOENT && event->attr.type != type && !extended_type) { @@ -11982,27 +12218,21 @@ static struct pmu *perf_init_event(struct perf_event *event) } if (ret) - pmu = ERR_PTR(ret); + return ERR_PTR(ret); - goto unlock; + return pmu; } list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) { ret = perf_try_init_event(pmu, event); if (!ret) - goto unlock; + return pmu; - if (ret != -ENOENT) { - pmu = ERR_PTR(ret); - goto unlock; - } + if (ret != -ENOENT) + return ERR_PTR(ret); } -fail: - pmu = ERR_PTR(-ENOENT); -unlock: - srcu_read_unlock(&pmus_srcu, idx); - return pmu; + return ERR_PTR(-ENOENT); } static void attach_sb_event(struct perf_event *event) @@ -12129,7 +12359,6 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, void *context, int cgroup_fd) { struct pmu *pmu; - struct perf_event *event; struct hw_perf_event *hwc; long err = -EINVAL; int node; @@ -12144,8 +12373,8 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, } node = (cpu >= 0) ? cpu_to_node(cpu) : -1; - event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO, - node); + struct perf_event *event __free(__free_event) = + kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO, node); if (!event) return ERR_PTR(-ENOMEM); @@ -12235,6 +12464,13 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, perf_event__state_init(event); + /* + * Hold SRCU critical section around perf_init_event(), until returning + * the fully formed event put on pmu->events_list. This ensures that + * perf_pmu_unregister() will see any in-progress event creation that + * races. + */ + guard(srcu)(&pmus_srcu); pmu = NULL; hwc = &event->hw; @@ -12252,51 +12488,43 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, * See perf_output_read(). */ if (has_inherit_and_sample_read(attr) && !(attr->sample_type & PERF_SAMPLE_TID)) - goto err_ns; + return ERR_PTR(-EINVAL); if (!has_branch_stack(event)) event->attr.branch_sample_type = 0; pmu = perf_init_event(event); - if (IS_ERR(pmu)) { - err = PTR_ERR(pmu); - goto err_ns; - } + if (IS_ERR(pmu)) + return (void*)pmu; /* * Disallow uncore-task events. Similarly, disallow uncore-cgroup * events (they don't make sense as the cgroup will be different * on other CPUs in the uncore mask). */ - if (pmu->task_ctx_nr == perf_invalid_context && (task || cgroup_fd != -1)) { - err = -EINVAL; - goto err_pmu; - } + if (pmu->task_ctx_nr == perf_invalid_context && (task || cgroup_fd != -1)) + return ERR_PTR(-EINVAL); if (event->attr.aux_output && - !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) { - err = -EOPNOTSUPP; - goto err_pmu; - } + !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) + return ERR_PTR(-EOPNOTSUPP); if (cgroup_fd != -1) { err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader); if (err) - goto err_pmu; + return ERR_PTR(err); } err = exclusive_event_init(event); if (err) - goto err_pmu; + return ERR_PTR(err); if (has_addr_filter(event)) { event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters, sizeof(struct perf_addr_filter_range), GFP_KERNEL); - if (!event->addr_filter_ranges) { - err = -ENOMEM; - goto err_per_task; - } + if (!event->addr_filter_ranges) + return ERR_PTR(-ENOMEM); /* * Clone the parent's vma offsets: they are valid until exec() @@ -12320,42 +12548,22 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { err = get_callchain_buffers(attr->sample_max_stack); if (err) - goto err_addr_filters; + return ERR_PTR(err); + event->attach_state |= PERF_ATTACH_CALLCHAIN; } } err = security_perf_event_alloc(event); if (err) - goto err_callchain_buffer; + return ERR_PTR(err); /* symmetric to unaccount_event() in _free_event() */ account_event(event); - return event; - -err_callchain_buffer: - if (!event->parent) { - if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) - put_callchain_buffers(); - } -err_addr_filters: - kfree(event->addr_filter_ranges); + scoped_guard (spinlock, &pmu->events_lock) + list_add(&event->pmu_list, &pmu->events); -err_per_task: - exclusive_event_destroy(event); - -err_pmu: - if (is_cgroup_event(event)) - perf_detach_cgroup(event); - if (event->destroy) - event->destroy(event); - module_put(pmu->module); -err_ns: - if (event->hw.target) - put_task_struct(event->hw.target); - call_rcu(&event->rcu_head, free_event_rcu); - - return ERR_PTR(err); + return_ptr(event); } static int perf_copy_attr(struct perf_event_attr __user *uattr, @@ -12741,6 +12949,10 @@ SYSCALL_DEFINE5(perf_event_open, if (err) goto err_fd; group_leader = fd_file(group)->private_data; + if (group_leader->state <= PERF_EVENT_STATE_REVOKED) { + err = -ENODEV; + goto err_group_fd; + } if (flags & PERF_FLAG_FD_OUTPUT) output_event = group_leader; if (flags & PERF_FLAG_FD_NO_GROUP) @@ -13288,10 +13500,11 @@ static void sync_child_event(struct perf_event *child_event) } static void -perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx) +perf_event_exit_event(struct perf_event *event, + struct perf_event_context *ctx, bool revoke) { struct perf_event *parent_event = event->parent; - unsigned long detach_flags = 0; + unsigned long detach_flags = DETACH_EXIT; if (parent_event) { /* @@ -13306,16 +13519,14 @@ perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx) * Do destroy all inherited groups, we don't care about those * and being thorough is better. */ - detach_flags = DETACH_GROUP | DETACH_CHILD; + detach_flags |= DETACH_GROUP | DETACH_CHILD; mutex_lock(&parent_event->child_mutex); } - perf_remove_from_context(event, detach_flags); + if (revoke) + detach_flags |= DETACH_GROUP | DETACH_REVOKE; - raw_spin_lock_irq(&ctx->lock); - if (event->state > PERF_EVENT_STATE_EXIT) - perf_event_set_state(event, PERF_EVENT_STATE_EXIT); - raw_spin_unlock_irq(&ctx->lock); + perf_remove_from_context(event, detach_flags); /* * Child events can be freed. @@ -13391,7 +13602,7 @@ static void perf_event_exit_task_context(struct task_struct *child) perf_event_task(child, child_ctx, 0); list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry) - perf_event_exit_event(child_event, child_ctx); + perf_event_exit_event(child_event, child_ctx, false); mutex_unlock(&child_ctx->mutex); @@ -13581,6 +13792,9 @@ inherit_event(struct perf_event *parent_event, if (parent_event->parent) parent_event = parent_event->parent; + if (parent_event->state <= PERF_EVENT_STATE_REVOKED) + return NULL; + child_event = perf_event_alloc(&parent_event->attr, parent_event->cpu, child, -- 2.47.0
