On 12/10, Oleg Nesterov wrote: > > I must have missed something, but... > > On 12/10, Lorenzo Stoakes wrote: > > > > @@ -1746,9 +1741,11 @@ static struct mm_struct *dup_mm(struct task_struct > > *tsk, > > if (!mm_init(mm, tsk, mm->user_ns)) > > goto fail_nomem; > > > > + uprobe_start_dup_mmap(); > > err = dup_mmap(mm, oldmm); > > if (err) > > - goto free_pt; > > + goto free_pt_end_uprobe; > > + uprobe_end_dup_mmap(); > > > > mm->hiwater_rss = get_mm_rss(mm); > > mm->hiwater_vm = mm->total_vm; > > @@ -1758,6 +1755,8 @@ static struct mm_struct *dup_mm(struct task_struct > > *tsk, > > > > return mm; > > > > +free_pt_end_uprobe: > > + uprobe_end_dup_mmap(); > > if dup_mmap() fails and "mm" is incomplete, then with this version > dup_mmap_sem > is dropped before __mmput/exit_mmap/etc. How can this help?
Easy to fix, but what ensures that another mmget(mm) is not possible until dup_mm() calls mmput() and drops dup_mmap_sem? Sorry, my understanding of mm/ is very limited... Oleg.
