Re: [syzbot] possible deadlock in register_for_each_vma

[Oleg Nesterov]

On 04/01, Hillf Danton wrote:
>
> If I dont misread it,  the lockdep chain will likely evolve from
>
>    event_mutex -> uprobe.register_rwsem -> dup_mmap_sem -> mm.mmap_lock ->
>    event_mutex
> to
>    dup_mmap_sem -> mm.mmap_lock -> dup_mmap_sem
>
> after this patch as both uprobe_register() and uprobe_unregister() would take
> dup_mmap_sem.

Hmm, please correct me, but I don't think so. I think mmap_lock -> dup_mmap_sem
is not possible.

Oleg.