On Thu, Apr 12, 2018 at 10:16 AM, David Lee <live4t...@gmail.com> wrote: >> > My team caught this issue too after switching to CentOS 7.4 with qemu-img >> > 2.9.0 >> > gdb shows exactly the same backtrace when the convert stuck, and we are on >> > NFS. >> > >> > Later we found the following: >> > 1. The stuck can happen on local storage, too. >> > 2. Replace qemu-img 2.9.0 with 2.6.0 and everything works smoothly again. >> > >> > BTW, we use "qemu-img convert" to convert qcow2 and its backing files into >> > a single qcow2 image. >> >> Maybe it is RHBZ 1508886? >> >> Fam > > > > Thanks, Fam. We just tracked down to this BZ too and are about to trying > the commit ef6dada8b44e1e7c4bec5c1115903af9af415b50
We tested qemu-kvm-ev-2.9.0-16.el7_4.14.1 - where from the source RPM we verified it does contain ef6dada8b44e1e7c4bec5c1115903af9af415b50 But the issue still exists. The convert got stuck if one of the old active overlay had been 'vol-resize'd with qemu monitor command to a larger size. This looks like a prerequisite but not sufficient condition to trigger this badness. -- Thanks, Li Qun