linux-kernel - Re: [PATCH v2] introduce atomic_pointer to fix a race condition in cancelable mcs spinlocks

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]

Date:	Mon, 2 Jun 2014 09:46:55 -0700
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Mikulas Patocka <mpatocka@...hat.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	jejb@...isc-linux.org, deller@....de,
	John David Anglin <dave.anglin@...l.net>,
	linux-parisc@...r.kernel.org, linux-kernel@...r.kernel.org,
	chegu_vinod@...com, Waiman.Long@...com, tglx@...utronix.de,
	riel@...hat.com, akpm@...ux-foundation.org, davidlohr@...com,
	hpa@...or.com, andi@...stfloor.org, aswin@...com,
	scott.norton@...com, Jason Low <jason.low2@...com>
Subject: Re: [PATCH v2] introduce atomic_pointer to fix a race condition in
 cancelable mcs spinlocks

On Mon, Jun 02, 2014 at 06:30:32PM +0200, Peter Zijlstra wrote:
> On Mon, Jun 02, 2014 at 06:25:25PM +0200, Peter Zijlstra wrote:
> > I'm almost inclined to just exclude parisc from using opt spinning.
> > 
> > That said, this patch still doesn't address the far more interesting
> > problem of actually finding these issues for these few weird archs.
> 
> So why do these archs provide xchg() and cmpxchg() at all? Wouldn't it
> be much simpler if archs that cannot sanely do this, not provide these
> primitives at all?

Such architectures would also need to avoid NO_HZ_FULL_SYSIDLE and
RCU_NOCB_CPU, but those are probably entirely reasonable restrictions.

							Thanx, Paul

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/