[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <Ze9bWkrD6UBZ2ErV@x1n>
Date: Mon, 11 Mar 2024 15:28:26 -0400
From: Peter Xu <peterx@...hat.com>
To: Axel Rasmussen <axelrasmussen@...gle.com>
Cc: David Hildenbrand <david@...hat.com>,
Mirsad Todorovac <mirsad.todorovac@....unizg.hr>,
linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>,
Shuah Khan <shuah@...nel.org>, linux-kselftest@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: BUG selftests/mm]
On Mon, Mar 11, 2024 at 11:59:59AM -0700, Axel Rasmussen wrote:
> I'd prefer not to require root or CAP_SYS_ADMIN or similar for
> UFFDIO_POISON, because those control access to lots more things
> besides, which we don't necessarily want the process using UFFD to be
> able to do. :/
>
> Ratelimiting seems fairly reasonable to me. I do see the concern about
> dropping some addresses though.
Do you know how much could an admin rely on such addresses? How frequent
would MCE generate normally in a sane system?
> Perhaps we can mitigate that concern by defining our own ratelimit
> interval/burst configuration?
Any details?
> Another idea would be to only ratelimit it if !CONFIG_DEBUG_VM or
> similar. Not sure if that's considered valid or not. :)
This, OTOH, sounds like an overkill..
I just checked again on the detail of ratelimit code, where we by default
it has:
#define DEFAULT_RATELIMIT_INTERVAL (5 * HZ)
#define DEFAULT_RATELIMIT_BURST 10
So it allows a 10 times burst rather than 2.. IIUC it means even if
there're continous 10 MCEs it won't get suppressed, until the 11th came, in
5 seconds interval. I think it means it's possibly even less of a concern
to directly use pr_err_ratelimited().
Thanks,
--
Peter Xu
Powered by blists - more mailing lists