Re: [RFC v8 PATCH 2/5] uprobes: introduce has_uprobes helper

[Oleg Nesterov]

On 08/22, Srikar Dronamraju wrote:
>
> * Vlastimil Babka <vbabka@xxxxxxx> [2018-08-22 12:55:59]:
>
> > On 08/15/2018 08:49 PM, Yang Shi wrote:
> > > We need check if mm or vma has uprobes in the following patch to check
> > > if a vma could be unmapped with holding read mmap_sem.

Confused... why can't we call uprobe_munmap() under read_lock(mmap_sem) ?

OK, it can race with find_active_uprobe() but I do not see anything really
wrong, and a false-positive MMF_RECALC_UPROBES is fine.

Again, I think we should simply kill uprobe_munmap(), but this needs another
discussion.

Oleg.