linux-kernel - Re: handle_exit_race && PF

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.DEB.2.21.1911061808030.1869@nanos.tec.linutronix.de>
Date:   Wed, 6 Nov 2019 18:42:13 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Oleg Nesterov <oleg@...hat.com>
cc:     Florian Weimer <fweimer@...hat.com>, Shawn Landden <shawn@....icu>,
        libc-alpha@...rceware.org, linux-api@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>,
        Arnd Bergmann <arnd@...db.de>,
        Deepa Dinamani <deepa.kernel@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Keith Packard <keithp@...thp.com>,
        Peter Zijlstra <peterz@...radead.org>
Subject: Re: handle_exit_race && PF_EXITING

On Wed, 6 Nov 2019, Oleg Nesterov wrote:
> 
> I think that (with or without this fix) handle_exit_race() logic needs
> cleanups, there is no reason for get_futex_value_locked(), we can drop
> ->pi_lock right after we see PF_EXITPIDONE. Lets discuss this later.

Which still is in atomic because the hash bucket lock is held, ergo
get_futex_value_locked() needs to stay for now.

So the only thing we could do is to reduce the pi_lock held section a bit.

Thanks,

	tglx