Re: [tip:locking/urgent] locking/mutex: Disable optimistic spinning on some architectures

Davidlohr Bueso
2014-07-18T03:07:49Z

On Wed, 2014-07-16 at 12:24 -0700, tip-bot for Peter Zijlstra wrote:
> Commit-ID: 4badad352a6bb202ec68afa7a574c0bb961e5ebc
> Gitweb: http://git.kernel.org/tip/4badad352a6bb202ec68afa7a574c0bb961e5ebc
> Author: Peter Zijlstra <peterz@infradead.org>
> AuthorDate: Fri, 6 Jun 2014 19:53:16 +0200
> Committer: Ingo Molnar <mingo@kernel.org>
> CommitDate: Wed, 16 Jul 2014 14:57:07 +0200
>
> locking/mutex: Disable optimistic spinning on some architectures
>
> The optimistic spin code assumes regular stores and cmpxchg() play nice;
> this is found to not be true for at least: parisc, sparc32, tile32,
> metag-lock1, arc-!llsc and hexagon.
>
> There is further wreckage, but this in particular seemed easy to
> trigger, so blacklist this.
>
> Opt in for known good archs.
>
> Signed-off-by: Peter Zijlstra <peterz@infradead.org>
> Reported-by: Mikulas Patocka <mpatocka@redhat.com>
> Cc: David Miller <davem@davemloft.net>
> Cc: Chris Metcalf <cmetcalf@tilera.com>
> Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
> Cc: Vineet Gupta <vgupta@synopsys.com>
> Cc: Jason Low <jason.low2@hp.com>
> Cc: Waiman Long <waiman.long@hp.com>
> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
> Cc: John David Anglin <dave.anglin@bell.net>
> Cc: James Hogan <james.hogan@imgtec.com>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Davidlohr Bueso <davidlohr@hp.com>
> Cc: stable@vger.kernel.org
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Russell King <linux@arm.linux.org.uk>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: sparclinux@vger.kernel.org
> Link: http://lkml.kernel.org/r/20140606175316.GV13930@laptop.programming.kicks-ass.net
> Signed-off-by: Ingo Molnar <mingo@kernel.org>

Cc'ing stable: this issue was reported to begin after commit fb0527bd,
so since v3.13.

Thanks,
Davidlohr