Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (86c76676) · Commits · 戴 / test

arch/x86/kernel/cpu/perf_event_intel.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -165,13 +165,13 @@ static struct extra_reg intel_snb_extra_regs[] __read_mostly = {
		INTEL_EVENT_EXTRA_REG(0xb7, MSR_OFFCORE_RSP_0, 0x3f807f8fffull, RSP_0),
		INTEL_EVENT_EXTRA_REG(0xbb, MSR_OFFCORE_RSP_1, 0x3f807f8fffull, RSP_1),
		INTEL_UEVENT_PEBS_LDLAT_EXTRA_REG(0x01cd),
		INTEL_UEVENT_PEBS_LDLAT_EXTRA_REG(0x01cd),
		EVENT_EXTRA_END
		};

		static struct extra_reg intel_snbep_extra_regs[] __read_mostly = {
		INTEL_EVENT_EXTRA_REG(0xb7, MSR_OFFCORE_RSP_0, 0x3fffff8fffull, RSP_0),
		INTEL_EVENT_EXTRA_REG(0xbb, MSR_OFFCORE_RSP_1, 0x3fffff8fffull, RSP_1),
		INTEL_UEVENT_PEBS_LDLAT_EXTRA_REG(0x01cd),
		EVENT_EXTRA_END
		};

include/linux/perf_event.h

+1 −2

Original line number	Diff line number	Diff line
		@@ -389,8 +389,7 @@ struct perf_event {
		/* mmap bits */
		struct mutex mmap_mutex;
		atomic_t mmap_count;
		int mmap_locked;
		struct user_struct *mmap_user;

		struct ring_buffer *rb;
		struct list_head rb_entry;

kernel/events/core.c

+161 −72

Original line number	Diff line number	Diff line
		@@ -196,9 +196,6 @@ static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
		static void update_context_time(struct perf_event_context *ctx);
		static u64 perf_event_time(struct perf_event *event);

		static void ring_buffer_attach(struct perf_event *event,
		struct ring_buffer *rb);

		void __weak perf_event_print_debug(void) { }

		extern __weak const char *perf_pmu_name(void)
		@@ -2918,6 +2915,7 @@ static void free_event_rcu(struct rcu_head *head)
		}

		static void ring_buffer_put(struct ring_buffer *rb);
		static void ring_buffer_detach(struct perf_event event, struct ring_buffer rb);

		static void free_event(struct perf_event *event)
		{
		@@ -2942,15 +2940,30 @@ static void free_event(struct perf_event *event)
		if (has_branch_stack(event)) {
		static_key_slow_dec_deferred(&perf_sched_events);
		/* is system-wide event */
		if (!(event->attach_state & PERF_ATTACH_TASK))
		if (!(event->attach_state & PERF_ATTACH_TASK)) {
		atomic_dec(&per_cpu(perf_branch_stack_events,
		event->cpu));
		}
		}
		}

		if (event->rb) {
		ring_buffer_put(event->rb);
		event->rb = NULL;
		struct ring_buffer *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);
		rb = event->rb;
		if (rb) {
		rcu_assign_pointer(event->rb, NULL);
		ring_buffer_detach(event, rb);
		ring_buffer_put(rb); /* could be last */
		}
		mutex_unlock(&event->mmap_mutex);
		}

		if (is_cgroup_event(event))
		@@ -3188,30 +3201,13 @@ static unsigned int perf_poll(struct file file, poll_table wait)
		unsigned int events = POLL_HUP;

		/*
		* Race between perf_event_set_output() and perf_poll(): perf_poll()
		* grabs the rb reference but perf_event_set_output() overrides it.
		* Here is the timeline for two threads T1, T2:
		* t0: T1, rb = rcu_dereference(event->rb)
		* t1: T2, old_rb = event->rb
		* t2: T2, event->rb = new rb
		* t3: T2, ring_buffer_detach(old_rb)
		* t4: T1, ring_buffer_attach(rb1)
		* t5: T1, poll_wait(event->waitq)
		*
		* To avoid this problem, we grab mmap_mutex in perf_poll()
		* thereby ensuring that the assignment of the new ring buffer
		* and the detachment of the old buffer appear atomic to perf_poll()
		* Pin the event->rb by taking event->mmap_mutex; otherwise
		* perf_event_set_output() can swizzle our rb and make us miss wakeups.
		*/
		mutex_lock(&event->mmap_mutex);

		rcu_read_lock();
		rb = rcu_dereference(event->rb);
		if (rb) {
		ring_buffer_attach(event, rb);
		rb = event->rb;
		if (rb)
		events = atomic_xchg(&rb->poll, 0);
		}
		rcu_read_unlock();

		mutex_unlock(&event->mmap_mutex);

		poll_wait(file, &event->waitq, wait);
		@@ -3521,16 +3517,12 @@ static void ring_buffer_attach(struct perf_event *event,
		return;

		spin_lock_irqsave(&rb->event_lock, flags);
		if (!list_empty(&event->rb_entry))
		goto unlock;

		if (list_empty(&event->rb_entry))
		list_add(&event->rb_entry, &rb->event_list);
		unlock:
		spin_unlock_irqrestore(&rb->event_lock, flags);
		}

		static void ring_buffer_detach(struct perf_event *event,
		struct ring_buffer *rb)
		static void ring_buffer_detach(struct perf_event event, struct ring_buffer rb)
		{
		unsigned long flags;

		@@ -3549,13 +3541,10 @@ static void ring_buffer_wakeup(struct perf_event *event)

		rcu_read_lock();
		rb = rcu_dereference(event->rb);
		if (!rb)
		goto unlock;

		if (rb) {
		list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
		wake_up_all(&event->waitq);

		unlock:
		}
		rcu_read_unlock();
		}

		@@ -3584,18 +3573,10 @@ static struct ring_buffer ring_buffer_get(struct perf_event event)

		static void ring_buffer_put(struct ring_buffer *rb)
		{
		struct perf_event event, n;
		unsigned long flags;

		if (!atomic_dec_and_test(&rb->refcount))
		return;

		spin_lock_irqsave(&rb->event_lock, flags);
		list_for_each_entry_safe(event, n, &rb->event_list, rb_entry) {
		list_del_init(&event->rb_entry);
		wake_up_all(&event->waitq);
		}
		spin_unlock_irqrestore(&rb->event_lock, flags);
		WARN_ON_ONCE(!list_empty(&rb->event_list));

		call_rcu(&rb->rcu_head, rb_free_rcu);
		}
		@@ -3605,26 +3586,100 @@ static void perf_mmap_open(struct vm_area_struct *vma)
		struct perf_event *event = vma->vm_file->private_data;

		atomic_inc(&event->mmap_count);
		atomic_inc(&event->rb->mmap_count);
		}

		/*
		* A buffer can be mmap()ed multiple times; either directly through the same
		* event, or through other events by use of perf_event_set_output().
		*
		* In order to undo the VM accounting done by perf_mmap() we need to destroy
		* the buffer here, where we still have a VM context. This means we need
		* to detach all events redirecting to us.
		*/
		static void perf_mmap_close(struct vm_area_struct *vma)
		{
		struct perf_event *event = vma->vm_file->private_data;

		if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
		unsigned long size = perf_data_size(event->rb);
		struct user_struct *user = event->mmap_user;
		struct ring_buffer *rb = event->rb;
		struct user_struct *mmap_user = rb->mmap_user;
		int mmap_locked = rb->mmap_locked;
		unsigned long size = perf_data_size(rb);

		atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
		vma->vm_mm->pinned_vm -= event->mmap_locked;
		atomic_dec(&rb->mmap_count);

		if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
		return;

		/* Detach current event from the buffer. */
		rcu_assign_pointer(event->rb, NULL);
		ring_buffer_detach(event, rb);
		mutex_unlock(&event->mmap_mutex);

		ring_buffer_put(rb);
		free_uid(user);
		/* If there's still other mmap()s of this buffer, we're done. */
		if (atomic_read(&rb->mmap_count)) {
		ring_buffer_put(rb); /* can't be last */
		return;
		}

		/*
		* No other mmap()s, detach from all other events that might redirect
		* into the now unreachable buffer. Somewhat complicated by the
		* fact that rb::event_lock otherwise nests inside mmap_mutex.
		*/
		again:
		rcu_read_lock();
		list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
		if (!atomic_long_inc_not_zero(&event->refcount)) {
		/*
		* This event is en-route to free_event() which will
		* detach it and remove it from the list.
		*/
		continue;
		}
		rcu_read_unlock();

		mutex_lock(&event->mmap_mutex);
		/*
		* Check we didn't race with perf_event_set_output() which can
		* swizzle the rb from under us while we were waiting to
		* acquire mmap_mutex.
		*
		* If we find a different rb; ignore this event, a next
		* iteration will no longer find it on the list. We have to
		* still restart the iteration to make sure we're not now
		* iterating the wrong list.
		*/
		if (event->rb == rb) {
		rcu_assign_pointer(event->rb, NULL);
		ring_buffer_detach(event, rb);
		ring_buffer_put(rb); /* can't be last, we still have one */
		}
		mutex_unlock(&event->mmap_mutex);
		put_event(event);

		/*
		* Restart the iteration; either we're on the wrong list or
		* destroyed its integrity by doing a deletion.
		*/
		goto again;
		}
		rcu_read_unlock();

		/*
		* It could be there's still a few 0-ref events on the list; they'll
		* get cleaned up by free_event() -- they'll also still have their
		* ref on the rb and will free it whenever they are done with it.
		*
		* Aside from that, this buffer is 'fully' detached and unmapped,
		* undo the VM accounting.
		*/

		atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
		vma->vm_mm->pinned_vm -= mmap_locked;
		free_uid(mmap_user);

		ring_buffer_put(rb); /* could be last */
		}

		static const struct vm_operations_struct perf_mmap_vmops = {
		@@ -3674,15 +3729,27 @@ static int perf_mmap(struct file file, struct vm_area_struct vma)
		return -EINVAL;

		WARN_ON_ONCE(event->ctx->parent_ctx);
		again:
		mutex_lock(&event->mmap_mutex);
		if (event->rb) {
		if (event->rb->nr_pages == nr_pages)
		atomic_inc(&event->rb->refcount);
		else
		if (event->rb->nr_pages != nr_pages) {
		ret = -EINVAL;
		goto unlock;
		}

		if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
		/*
		* Raced against perf_mmap_close() through
		* perf_event_set_output(). Try again, hope for better
		* luck.
		*/
		mutex_unlock(&event->mmap_mutex);
		goto again;
		}

		goto unlock;
		}

		user_extra = nr_pages + 1;
		user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);

		@@ -3720,12 +3787,16 @@ static int perf_mmap(struct file file, struct vm_area_struct vma)
		ret = -ENOMEM;
		goto unlock;
		}
		rcu_assign_pointer(event->rb, rb);

		atomic_set(&rb->mmap_count, 1);
		rb->mmap_locked = extra;
		rb->mmap_user = get_current_user();

		atomic_long_add(user_extra, &user->locked_vm);
		event->mmap_locked = extra;
		event->mmap_user = get_current_user();
		vma->vm_mm->pinned_vm += event->mmap_locked;
		vma->vm_mm->pinned_vm += extra;

		ring_buffer_attach(event, rb);
		rcu_assign_pointer(event->rb, rb);

		perf_event_update_userpage(event);

		@@ -3734,7 +3805,11 @@ unlock:
		atomic_inc(&event->mmap_count);
		mutex_unlock(&event->mmap_mutex);

		vma->vm_flags \|= VM_DONTEXPAND \| VM_DONTDUMP;
		/*
		* Since pinned accounting is per vm we cannot allow fork() to copy our
		* vma.
		*/
		vma->vm_flags \|= VM_DONTCOPY \| VM_DONTEXPAND \| VM_DONTDUMP;
		vma->vm_ops = &perf_mmap_vmops;

		return ret;
		@@ -6412,6 +6487,8 @@ set:
		if (atomic_read(&event->mmap_count))
		goto unlock;

		old_rb = event->rb;

		if (output_event) {
		/* get the rb we want to redirect to */
		rb = ring_buffer_get(output_event);
		@@ -6419,16 +6496,28 @@ set:
		goto unlock;
		}

		old_rb = event->rb;
		rcu_assign_pointer(event->rb, rb);
		if (old_rb)
		ring_buffer_detach(event, old_rb);

		if (rb)
		ring_buffer_attach(event, rb);

		rcu_assign_pointer(event->rb, rb);

		if (old_rb) {
		ring_buffer_put(old_rb);
		/*
		* Since we detached before setting the new rb, so that we
		* could attach the new rb, we could have missed a wakeup.
		* Provide it now.
		*/
		wake_up_all(&event->waitq);
		}

		ret = 0;
		unlock:
		mutex_unlock(&event->mmap_mutex);

		if (old_rb)
		ring_buffer_put(old_rb);
		out:
		return ret;
		}

kernel/events/internal.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -31,6 +31,10 @@ struct ring_buffer {
		spinlock_t event_lock;
		struct list_head event_list;

		atomic_t mmap_count;
		unsigned long mmap_locked;
		struct user_struct *mmap_user;

		struct perf_event_mmap_page *user_page;
		void *data_pages[0];
		};

kernel/kprobes.c

+20 −10

Original line number	Diff line number	Diff line
		@@ -467,6 +467,7 @@ static struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr)
		/* Optimization staging list, protected by kprobe_mutex */
		static LIST_HEAD(optimizing_list);
		static LIST_HEAD(unoptimizing_list);
		static LIST_HEAD(freeing_list);

		static void kprobe_optimizer(struct work_struct *work);
		static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
		@@ -504,7 +505,7 @@ static __kprobes void do_optimize_kprobes(void)
		* Unoptimize (replace a jump with a breakpoint and remove the breakpoint
		* if need) kprobes listed on unoptimizing_list.
		*/
		static __kprobes void do_unoptimize_kprobes(struct list_head *free_list)
		static __kprobes void do_unoptimize_kprobes(void)
		{
		struct optimized_kprobe op, tmp;

		@@ -515,9 +516,9 @@ static __kprobes void do_unoptimize_kprobes(struct list_head *free_list)
		/* Ditto to do_optimize_kprobes */
		get_online_cpus();
		mutex_lock(&text_mutex);
		arch_unoptimize_kprobes(&unoptimizing_list, free_list);
		arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list);
		/* Loop free_list for disarming */
		list_for_each_entry_safe(op, tmp, free_list, list) {
		list_for_each_entry_safe(op, tmp, &freeing_list, list) {
		/* Disarm probes if marked disabled */
		if (kprobe_disabled(&op->kp))
		arch_disarm_kprobe(&op->kp);
		@@ -536,11 +537,11 @@ static __kprobes void do_unoptimize_kprobes(struct list_head *free_list)
		}

		/* Reclaim all kprobes on the free_list */
		static __kprobes void do_free_cleaned_kprobes(struct list_head *free_list)
		static __kprobes void do_free_cleaned_kprobes(void)
		{
		struct optimized_kprobe op, tmp;

		list_for_each_entry_safe(op, tmp, free_list, list) {
		list_for_each_entry_safe(op, tmp, &freeing_list, list) {
		BUG_ON(!kprobe_unused(&op->kp));
		list_del_init(&op->list);
		free_aggr_kprobe(&op->kp);
		@@ -556,8 +557,6 @@ static __kprobes void kick_kprobe_optimizer(void)
		/* Kprobe jump optimizer */
		static __kprobes void kprobe_optimizer(struct work_struct *work)
		{
		LIST_HEAD(free_list);

		mutex_lock(&kprobe_mutex);
		/* Lock modules while optimizing kprobes */
		mutex_lock(&module_mutex);
		@@ -566,7 +565,7 @@ static __kprobes void kprobe_optimizer(struct work_struct *work)
		* Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
		* kprobes before waiting for quiesence period.
		*/
		do_unoptimize_kprobes(&free_list);
		do_unoptimize_kprobes();

		/*
		* Step 2: Wait for quiesence period to ensure all running interrupts
		@@ -581,7 +580,7 @@ static __kprobes void kprobe_optimizer(struct work_struct *work)
		do_optimize_kprobes();

		/* Step 4: Free cleaned kprobes after quiesence period */
		do_free_cleaned_kprobes(&free_list);
		do_free_cleaned_kprobes();

		mutex_unlock(&module_mutex);
		mutex_unlock(&kprobe_mutex);
		@@ -723,8 +722,19 @@ static void __kprobes kill_optimized_kprobe(struct kprobe *p)
		if (!list_empty(&op->list))
		/* Dequeue from the (un)optimization queue */
		list_del_init(&op->list);

		op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;

		if (kprobe_unused(p)) {
		/* Enqueue if it is unused */
		list_add(&op->list, &freeing_list);
		/*
		* Remove unused probes from the hash list. After waiting
		* for synchronization, this probe is reclaimed.
		* (reclaiming is done by do_free_cleaned_kprobes().)
		*/
		hlist_del_rcu(&op->kp.hlist);
		}

		/* Don't touch the code, because it is already freed. */
		arch_remove_optimized_kprobe(op);
		}

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