Re: blk-mq crash under KVM in multiqueue block code (with virtio-blk and ext4)
From: Ming Lei <tom.leiming@gmail.com>
Date: 2014-09-17 10:01:31
Also in:
kvm, lkml
On Wed, Sep 17, 2014 at 3:59 PM, Christian Borntraeger [off-list ref] wrote:
On 09/12/2014 10:09 PM, Christian Borntraeger wrote:quoted
On 09/12/2014 01:54 PM, Ming Lei wrote:quoted
On Thu, Sep 11, 2014 at 6:26 PM, Christian Borntraeger [off-list ref] wrote:quoted
Folks, we have seen the following bug with 3.16 as a KVM guest. It suspect the blk-mq rework that happened between 3.15 and 3.16, but it can be something completely different.Care to share how you reproduce the issue?Host with 16GB RAM 32GB swap. 15 guest all with 2 GB RAM (and varying amount of CPUs). All do heavy file I/O. It did not happen with 3.15/3.15 in guest/host and does happen with 3.16/3.16. So our next step is to check 3.15/3.16 and 3.16/3.15 to identify if its host memory mgmt or guest block layer.The crashed happen pretty randomly, but when they happen it seems that its the same trace as below. This makes memory corruption by host vm less likely and some thing wrong in blk-mq more likely I guess
Maybe you can try these patches because atomic op can be reordered on S390: http://marc.info/?l=linux-kernel&m=141094730828533&w=2 http://marc.info/?l=linux-kernel&m=141094730828534&w=2 Thanks -- Ming Lei