linux-kernel - Re: [PATCH 2/2] locking/rwsem: Disable optimistic spinning for PA-RISC

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:	Fri, 6 Jun 2014 13:19:59 -0400
From:	Chris Metcalf <cmetcalf@...era.com>
To:	Peter Zijlstra <peterz@...radead.org>,
	James Bottomley <James.Bottomley@...senPartnership.com>
CC:	Davidlohr Bueso <davidlohr@...com>, <mingo@...nel.org>,
	<mpatocka@...hat.com>, <torvalds@...ux-foundation.org>,
	<jason.low2@...com>, <waiman.long@...com>, <jejb@...isc-linux.org>,
	<paulmck@...ux.vnet.ibm.com>, <dave.anglin@...l.net>,
	<aswin@...com>, <linux-kernel@...r.kernel.org>,
	<linux-parisc@...r.kernel.org>, <davem@...emloft.net>,
	<james.hogan@...tec.com>, <vgupta@...opsys.com>
Subject: Re: [PATCH 2/2] locking/rwsem: Disable optimistic spinning for PA-RISC

On 6/6/2014 1:11 PM, Peter Zijlstra wrote:
> The thing is, all these archs are broken beyond this particular problem,
> Mikulas Patocka found a number of other spots.
>
> In any case, sure I can exclude more. Although ideally someone goes do
> that __atomic sparse thing to flush out all this.
>
> ---
> Subject: locking, mutex: Disable optimistic spinning on !RMW archs
>
> For some archs a regular store does not play nice with cmpxchg(), the
> optimistic spinning code (and various other places not caught by this)
> break this assumption and make things go boom.
>
> Until something better is found, disable optimistic spinning for these
> archs.
>
> [..]
>   
> +config ARCH_NO_ATOMIC_RMW
> +	def_bool y
> +	depends on PARISC || SPARC32 || METAG_ATOMICITY_LOCK1 || (TILE && !TILEGX) || (ARC && !ARC_HAS_LLSC)

For tile:

Acked-by: Chris Metcalf <cmetcalf@...era.com>

But you should use "TILEPRO" (added in kernel 3.5) instead of "(TILE && !TILEGX)".

-- 
Chris Metcalf, Tilera Corp.
http://www.tilera.com

--
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/