perf_counter: fix the mlock accounting (ebb3c4c4) · Commits · 戴 / test

kernel/perf_counter.c

+21 −12

Original line number	Diff line number	Diff line
		@@ -1461,6 +1461,7 @@ static void perf_mmap_close(struct vm_area_struct *vma)

		if (atomic_dec_and_mutex_lock(&counter->mmap_count,
		&counter->mmap_mutex)) {
		vma->vm_mm->locked_vm -= counter->data->nr_pages + 1;
		perf_mmap_data_free(counter);
		mutex_unlock(&counter->mmap_mutex);
		}
		@@ -1499,24 +1500,32 @@ static int perf_mmap(struct file file, struct vm_area_struct vma)
		if (vma->vm_pgoff != 0)
		return -EINVAL;

		locked = vma_size >> PAGE_SHIFT;
		locked += vma->vm_mm->locked_vm;
		mutex_lock(&counter->mmap_mutex);
		if (atomic_inc_not_zero(&counter->mmap_count)) {
		if (nr_pages != counter->data->nr_pages)
		ret = -EINVAL;
		goto unlock;
		}

		locked = vma->vm_mm->locked_vm;
		locked += nr_pages + 1;

		lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
		lock_limit >>= PAGE_SHIFT;

		if ((locked > lock_limit) && !capable(CAP_IPC_LOCK))
		return -EPERM;

		mutex_lock(&counter->mmap_mutex);
		if (atomic_inc_not_zero(&counter->mmap_count))
		goto out;
		if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
		ret = -EPERM;
		goto unlock;
		}

		WARN_ON(counter->data);
		ret = perf_mmap_data_alloc(counter, nr_pages);
		if (!ret)
		if (ret)
		goto unlock;

		atomic_set(&counter->mmap_count, 1);
		out:
		vma->vm_mm->locked_vm += nr_pages + 1;
		unlock:
		mutex_unlock(&counter->mmap_mutex);

		vma->vm_flags &= ~VM_MAYWRITE;