@@ -2432,25 +2432,19 @@ static struct mm_struct *find_mm_struct(pid_t pid, nodemask_t *mem_nodes)
return current->mm;
}
- /* Find the mm_struct */
- rcu_read_lock();
- task = find_task_by_vpid(pid);
+ task = find_get_task_by_vpid(pid);
if (!task) {
- rcu_read_unlock();
return ERR_PTR(-ESRCH);
}
- get_task_struct(task);
/*
* Check if this process has the right to modify the specified
* process. Use the regular "ptrace_may_access()" checks.
*/
if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
- rcu_read_unlock();
mm = ERR_PTR(-EPERM);
goto out;
}
- rcu_read_unlock();
mm = ERR_PTR(security_task_movememory(task));
if (IS_ERR(mm))
Use find_get_task_by_vpid() to replace the task_struct find logic in find_mm_struct(), note that this patch move the ptrace_may_access() call out from rcu_read_lock() scope, this is ok because it actually does not need it, find_get_task_by_vpid() already get the pid and task safely, ptrace_may_access() can use the task safely, like what sched_core_share_pid() similarly do. Signed-off-by: Nanyong Sun <sunnanyong@huawei.com> --- mm/migrate.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-)