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: <87v8budqdz.ffs@tglx>
Date:   Thu, 28 Sep 2023 21:55:20 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     linux-kernel@...r.kernel.org,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Boqun Feng <boqun.feng@...il.com>,
        "H . Peter Anvin" <hpa@...or.com>, Paul Turner <pjt@...gle.com>,
        linux-api@...r.kernel.org, Christian Brauner <brauner@...nel.org>,
        Florian Weimer <fw@...eb.enyo.de>, David.Laight@...LAB.COM,
        carlos@...hat.com, Peter Oskolkov <posk@...k.io>,
        Alexander Mikhalitsyn <alexander@...alicyn.com>,
        Chris Kennelly <ckennelly@...gle.com>,
        Ingo Molnar <mingo@...hat.com>,
        Darren Hart <dvhart@...radead.org>,
        Davidlohr Bueso <dave@...olabs.net>,
        André Almeida 
        <andrealmeid@...lia.com>, libc-alpha@...rceware.org,
        Steven Rostedt <rostedt@...dmis.org>,
        Jonathan Corbet <corbet@....net>,
        Noah Goldstein <goldstein.w.n@...il.com>,
        Daniel Colascione <dancol@...gle.com>, longman@...hat.com,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Subject: Re: [RFC PATCH v2 4/4] selftests/rseq: Implement rseq_mutex test
 program

On Mon, May 29 2023 at 15:14, Mathieu Desnoyers wrote:
> +static void rseq_lock_slowpath(struct rseq_mutex *lock)
> +{
> +	int i = 0;
> +
> +	for (;;) {
> +		struct rseq_abi_sched_state *expected = NULL, *self = rseq_get_sched_state(rseq_get_abi());
> +
> +		if (__atomic_compare_exchange_n(&lock->owner, &expected, self, false,
> +						__ATOMIC_ACQUIRE, __ATOMIC_RELAXED))
> +			break;
> +		//TODO: use rseq critical section to protect dereference of owner thread's
> +		//rseq_abi_sched_state, combined with rseq fence at thread reclaim.
> +		if ((RSEQ_READ_ONCE(expected->state) & RSEQ_ABI_SCHED_STATE_FLAG_ON_CPU) &&

For robust and PI futexes the futex value is an ABI between kernel and
user space. Sure, this is only meant for demonstration, but it's the
wrong direction.

Thanks,

        tglx






Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ