-static struct mm_struct *__check_mem_permission(struct task_struct *task)
-{
- struct mm_struct *mm;
-
- mm = get_task_mm(task);
- if (!mm)
- return ERR_PTR(-EINVAL);
-
- /*
- * A task can always look at itself, in case it chooses
- * to use system calls instead of load instructions.
- */
- if (task == current)
- return mm;
-
- /*
- * If current is actively ptrace'ing, and would also be
- * permitted to freshly attach with ptrace now, permit it.
- */
- if (task_is_stopped_or_traced(task)) {
- int match;
- rcu_read_lock();
- match = (ptrace_parent(task) == current);
- rcu_read_unlock();
- if (match && ptrace_may_access(task, PTRACE_MODE_ATTACH))
- return mm;
- }
-
- /*
- * No one else is allowed.
- */
- mmput(mm);
- return ERR_PTR(-EPERM);
-}
-
-/*
- * If current may access user memory in @task return a reference to the
- * corresponding mm, otherwise ERR_PTR.
- */
-static struct mm_struct *check_mem_permission(struct task_struct *task)
-{
- struct mm_struct *mm;
- int err;
-
- /*
- * Avoid racing if task exec's as we might get a new mm but validate
- * against old credentials.
- */
- err = mutex_lock_killable(&task->signal->cred_guard_mutex);
- if (err)
- return ERR_PTR(err);
-
- mm = __check_mem_permission(task);
- mutex_unlock(&task->signal->cred_guard_mutex);
-
- return mm;
-}
-
-struct mm_struct *mm_for_maps(struct task_struct *task)