From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: [040/111] xen: Do not suspend IPI IRQs. Date: Wed, 11 Aug 2010 16:54:21 -0700 Message-ID: <20100811235459.189944864@clark.site> References: <20100811235623.GA24440@kroah.com> Return-path: In-Reply-To: <20100811235623.GA24440@kroah.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Jeremy Fitzhardinge , xen-devel@lists.xensource.com, Ian Campbell , Thomas Gleixner , akpm@linux-foundation.org, torvalds@linux-foundation.org, stable-review@kernel.org, alan@lxorguk.ukuu.org.uk List-Id: xen-devel@lists.xenproject.org 2.6.32-stable review patch. If anyone has any objections, please let us know. ------------------ From: Ian Campbell commit 4877c737283813bdb4bebfa3168c1585f6e3a8ca upstream. In general the semantics of IPIs are that they are are expected to continue functioning after dpm_suspend_noirq(). Specifically I have seen a deadlock between the callfunc IPI and the stop machine used by xen's do_suspend() routine. If one CPU has already called dpm_suspend_noirq() then there is a window where it can be sent a callfunc IPI before all the other CPUs have entered stop_cpu(). If this happens then the first CPU ends up spinning in stop_cpu() waiting for the other to rendezvous in state STOPMACHINE_PREPARE while the other is spinning in csd_lock_wait(). Signed-off-by: Ian Campbell Cc: Jeremy Fitzhardinge Cc: xen-devel@lists.xensource.com LKML-Reference: <1280398595-29708-4-git-send-email-ian.campbell@citrix.com> Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- drivers/xen/events.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -535,6 +535,7 @@ int bind_ipi_to_irqhandler(enum ipi_vect if (irq < 0) return irq; + irqflags |= IRQF_NO_SUSPEND; retval = request_irq(irq, handler, irqflags, devname, dev_id); if (retval != 0) { unbind_from_irq(irq);