Am 10.06.2015 um 11:34 schrieb Fam Zheng: > On Wed, 06/10 11:18, Christian Borntraeger wrote: >> Am 10.06.2015 um 04:12 schrieb Fam Zheng: >>> On Tue, 06/09 11:01, Christian Borntraeger wrote: >>>> Am 09.06.2015 um 04:28 schrieb Fam Zheng: >>>>> On Tue, 06/02 16:36, Christian Borntraeger wrote: >>>>>> Paolo, >>>>>> >>>>>> I bisected >>>>>> commit a0710f7995f914e3044e5899bd8ff6c43c62f916 >>>>>> Author: Paolo Bonzini <pbonz...@redhat.com> >>>>>> AuthorDate: Fri Feb 20 17:26:52 2015 +0100 >>>>>> Commit: Kevin Wolf <kw...@redhat.com> >>>>>> CommitDate: Tue Apr 28 15:36:08 2015 +0200 >>>>>> >>>>>> iothread: release iothread around aio_poll >>>>>> >>>>>> to cause a problem with hanging guests. >>>>>> >>>>>> Having many guests all with a kernel/ramdisk (via -kernel) and >>>>>> several null block devices will result in hangs. All hanging >>>>>> guests are in partition detection code waiting for an I/O to return >>>>>> so very early maybe even the first I/O. >>>>>> >>>>>> Reverting that commit "fixes" the hangs. >>>>>> Any ideas?
For what its worth, I can no longer reproduce the issue on current master + cherry-pick of a0710f7995f (iothread: release iothread around aio_poll) bisect tells me that commit 53ec73e264f481b79b52efcadc9ceb8f8996975c Author: Fam Zheng <f...@redhat.com> AuthorDate: Fri May 29 18:53:14 2015 +0800 Commit: Stefan Hajnoczi <stefa...@redhat.com> CommitDate: Tue Jul 7 14:27:14 2015 +0100 block: Use bdrv_drain to replace uncessary bdrv_drain_all made the problem will blk-null go away. I still dont understand why. Christian