On 2018/10/08 10:19, Yong-Taek Lee wrote: > @@ -1056,6 +1056,7 @@ static int __set_oom_adj(struct file *file, int > oom_adj, bool legacy) > struct mm_struct *mm = NULL; > struct task_struct *task; > int err = 0; > + int mm_users = 0; > > task = get_proc_task(file_inode(file)); > if (!task) > @@ -1092,7 +1093,8 @@ static int __set_oom_adj(struct file *file, int > oom_adj, bool legacy) > struct task_struct *p = find_lock_task_mm(task); > > if (p) { > - if (atomic_read(&p->mm->mm_users) > 1) { > + mm_users = atomic_read(&p->mm->mm_users); > + if ((mm_users > 1) && (mm_users != > get_nr_threads(p))) {
How can this work (even before this patch)? When clone(CLONE_VM without CLONE_THREAD/CLONE_SIGHAND) is requested, copy_process() calls copy_signal() in order to copy sig->oom_score_adj and sig->oom_score_adj_min before calling copy_mm() in order to increment mm->mm_users, doesn't it? Then, we will get two different "struct signal_struct" with different oom_score_adj/oom_score_adj_min but one "struct mm_struct" shared by two thread groups. > mm = p->mm; > atomic_inc(&mm->mm_count); > }