Re: [PATCH] cred: Use RCU primitives to access RCU pointers

Oleg Nesterov
2020-01-28T11:48:35Z

On 01/28, Jann Horn wrote:
>
> On Tue, Jan 28, 2020 at 8:28 AM Amol Grover <frextrite@gmail.com> wrote:
> > task_struct.cred and task_struct.real_cred are annotated by __rcu,
>
> task_struct.cred doesn't actually have RCU semantics though, see
> commit d7852fbd0f0423937fa287a598bfde188bb68c22. For task_struct.cred,
> it would probably be more correct to remove the __rcu annotation?

Yes, but get_task_cred() assumes it has RCU semantics... To be honest
I didn't know we have this helper. Can't it race with revert_creds() in
do_faccessat() ?

Oleg.