From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: Re: [PATCH] SMP dom0 boot fix Date: Fri, 28 Oct 2005 16:15:12 +0100 Message-ID: References: <5916684ed3d62883c5aa18c358b24b21@cl.cam.ac.uk> <20051028145930.GL22394@us.ibm.com> Mime-Version: 1.0 (Apple Message framework v623) Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20051028145930.GL22394@us.ibm.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: Ryan Harper Cc: Ian Pratt , xen-devel List-Id: xen-devel@lists.xenproject.org On 28 Oct 2005, at 15:59, Ryan Harper wrote: > At this point send_IPI_allbutself() has been invoked and the system > just sits and waits on CPU1 to run the function. But, CPU1's > evtchn_upcall_mask was set (1), so I'm guessing the pending interrupt > is never acknowledged. Okay, the good news is that's the same bug I was able to repro last week. Turns out that CPU1's upcall mask is getting weirdly set under its feet. Since it's waiting on the big kernel lock, which is held by CPU0, which is waiting for acknowledgement of an interrupt in CPU1, we have a deadlock. Given the problem is in that one changeset, this can't be hard to track down now. -- Keir