From: Florian Weimer <fweimer@redhat.com>
To: Zack Weinberg <zackw@panix.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
"Carlos O'Donell" <carlos@redhat.com>,
Shawn Landden <shawn@git.icu>,
GNU C Library <libc-alpha@sourceware.org>,
linux-api@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
Deepa Dinamani <deepa.kernel@gmail.com>,
Oleg Nesterov <oleg@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Keith Packard <keithp@keithp.com>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [RFC v2 PATCH] futex: extend set_robust_list to allow 2 locking ABIs at the same time.
Date: Wed, 06 Nov 2019 15:04:17 +0100 [thread overview]
Message-ID: <87a799nlsu.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <CAKCAbMjYBpTjwyMJkkENps09o4KFoQAb_KOKp4g0BtWUXjYAzQ@mail.gmail.com> (Zack Weinberg's message of "Wed, 6 Nov 2019 09:00:51 -0500")
* Zack Weinberg:
> On Tue, Nov 5, 2019 at 9:28 AM Thomas Gleixner <tglx@linutronix.de> wrote:
>>
>> The real issue is that the robust list could be circular by incident or
>> malice and there is no way for the kernel to figure that out. That would
>> prevent the task from exiting and make it iterate over the list until
>> doomsday, i.e. a nice unpriviledged DoS.
>
> Why can't the kernel use the standard tortoise-and-hare algorithm for
> detecting circular linked lists here?
It's not guaranteed to terminate if the list is in shared memory.
Thanks,
Florian
next prev parent reply other threads:[~2019-11-06 14:04 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-04 0:29 [RFC v2 PATCH] futex: extend set_robust_list to allow 2 locking ABIs at the same time Shawn Landden
2019-11-04 0:51 ` Shawn Landden
2019-11-04 15:37 ` Thomas Gleixner
2019-11-05 0:10 ` Thomas Gleixner
2019-11-05 9:48 ` Florian Weimer
2019-11-05 9:59 ` Thomas Gleixner
2019-11-05 10:06 ` Florian Weimer
2019-11-05 11:56 ` Thomas Gleixner
2019-11-05 14:10 ` Carlos O'Donell
2019-11-05 14:27 ` Florian Weimer
2019-11-05 14:53 ` Thomas Gleixner
2019-11-05 14:27 ` Thomas Gleixner
2019-11-05 14:33 ` Florian Weimer
2019-11-05 14:48 ` Thomas Gleixner
2019-11-06 14:00 ` Zack Weinberg
2019-11-06 14:04 ` Florian Weimer [this message]
2019-11-05 15:27 ` handle_exit_race && PF_EXITING Oleg Nesterov
2019-11-05 17:28 ` Thomas Gleixner
2019-11-05 17:59 ` Thomas Gleixner
2019-11-05 18:56 ` Thomas Gleixner
2019-11-05 19:19 ` Thomas Gleixner
2019-11-06 8:55 ` Oleg Nesterov
2019-11-06 9:53 ` Thomas Gleixner
2019-11-06 10:35 ` Oleg Nesterov
2019-11-06 11:07 ` Thomas Gleixner
2019-11-06 12:11 ` Oleg Nesterov
2019-11-06 13:38 ` Thomas Gleixner
2019-11-06 17:42 ` Thomas Gleixner
2019-11-07 15:51 ` Oleg Nesterov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87a799nlsu.fsf@oldenburg2.str.redhat.com \
--to=fweimer@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=carlos@redhat.com \
--cc=catalin.marinas@arm.com \
--cc=deepa.kernel@gmail.com \
--cc=keithp@keithp.com \
--cc=libc-alpha@sourceware.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=oleg@redhat.com \
--cc=peterz@infradead.org \
--cc=shawn@git.icu \
--cc=tglx@linutronix.de \
--cc=zackw@panix.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox