On Sun, 2018-06-24 at 22:30 +0200, Armin Größlinger wrote: > Hello NFS developers, > > I've written to this list before [1],[2] concerning uninterruptible > hung > tasks in clients using NFSv4.0 with Kerberos. I have also written > scripts (which can be cloned from [3]) which help to reproduce the > hangs > by configuring two virtual machines with the required setup and a > test > program which triggers the hangs rather quickly (see [2] for > details). > > Meanwhile, I have been able to do some bisecting of kernel sources to > find a commit which exposes the hangs. It seems that since commit > > 2aca5b869ace67a63aab895659e5dc14c33a4d6e > SUNRPC: Add missing support for RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT > > (introduced with v3.18-rc1) the uninterruptible hangs occur. When I > revert this commit, then I do not observe the uninterruptible hangs. > I've tested this on Ubuntu 16.04's 4.4 kernel and Debian 9's 4.9 > kernel > and several stock kernels. That's the patch that implements this part of the NFSv4 spec: https://tools.ietf.org/html/rfc7530#section-3.1.1 So are you seeing the connection break when these hangs occur? If the connection hasn't broken, then the problem is more likely to be the server silently dropping requests, and hence failing to meet the obligation to reply to the client's RPC call (as spelled out in the above section of the spec). -- Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@xxxxxxxxxxxxxxx ��.n��������+%������w��{.n�����{��w��� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
