Kenneth Porter wrote: > --On Friday, October 19, 2018 2:33 PM -0700 Elliott Balsley > <elliott at altsystems.com> wrote: > >> I don't have a solution, but I wanted to point out this same hang >> happened to me recently with a Myricom 10Gb card. Apparently Myricom >> drivers do not support CentOS 7 smb connections, although HTTP traffic >> works fine. I solved it by switching to a different NIC. > > The mount works fine for me. It's only the automount that hangs, and only > since a few months ago. > > I had it happen again today when my LetsEncrypt cert renewed and the > dovecot (IMAP) server restarted. Dovecot checks all the mountpoints (in > case any have mail folders on them) and hung on restart. I shelled in and > ran df and it also hung. I logged in yet another session and tried to ls > the mountpoint and that hung completing the directory name. > > Here's what I see in /var/log/messages when dovecot hangs and I manually > mount the shares from another shell session. SELinux is in permissive > mode. > > Oct 26 09:11:39 saruman systemd: Mounting NAS1 share 1... > Oct 26 09:11:39 saruman systemd: Failed to expire automount, ignoring: No > such device Oct 26 09:11:39 saruman systemd: Mounted NAS1 share 1. > Oct 26 09:11:45 saruman kernel: INFO: task dovecot:831 blocked for more > than 120 seconds. Oct 26 09:11:45 saruman kernel: "echo 0 > > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > Oct 26 09:11:45 saruman kernel: dovecot D ffff9994adfa3f40 0 > 831 1 0x00000084 > Oct 26 09:11:45 saruman kernel: Call Trace: > Oct 26 09:11:45 saruman kernel: [<ffffffff85f1890c>] ? > __schedule+0x41c/0xa20 > Oct 26 09:11:45 saruman kernel: [<ffffffff85f18f39>] schedule+0x29/0x70 > Oct 26 09:11:45 saruman kernel: [<ffffffff85f168a9>] > schedule_timeout+0x239/0x2c0 Oct 26 09:11:45 saruman kernel: > [<ffffffff858beb96>] ? finish_wait+0x56/0x70 > Oct 26 09:11:45 saruman kernel: [<ffffffff85f16ff2>] ? > mutex_lock+0x12/0x2f Oct 26 09:11:45 saruman kernel: [<ffffffff85ab4e00>] > ? <snip> Wait a minute: are you running IPv6? What we see is that if a system doesn't get its IPv6 address, NFSv4 goes preferentially for that, and if it has that, and looses it, it will *NOT* fall back to IPv4, but hangs. mark