> On 4/13/21 11:36 PM, Chris Schanzle via CentOS wrote: >> On 4/13/21 5:00 PM, Frank Cox wrote: >>> On Tue, 13 Apr 2021 22:29:26 +0200 >>> Simon Matter wrote: >>> >>>> You could try running strace on the hanging process so see what it's >>>> doing. >>> [frankcox at mutt temp]$ rsync -avv ../temp/ jeff:temp >>> opening connection using: ssh jeff rsync --server -vvlogDtpre.iLsfxC . > temp (7 args) >>> sending incremental file list >>> delta-transmission enabled >>> abc is uptodate >>> total: matches=0 hash_hits=0 false_alarms=0 data=0 >>> >>> Leaving that sit there apparently doing nothing (but still not giving >>> me my cursor back) I switched to another terminal window and did the >>> following: >>> >>> [frankcox at mutt ~]$ ps -FA | grep rsync >>> frankcox 5400 2435 0 60586 3160 5 14:52 pts/0 00:00:00 >>> rsync -avv ../temp/ jeff:temp >>> frankcox 5401 5400 0 67980 7440 1 14:52 pts/0 00:00:00 ssh >> jeff rsync --server -vvlogDtpre.iLsfxC . temp >>> frankcox 5526 5416 0 55476 1076 3 14:53 pts/1 00:00:00 >>> grep --color=auto rsync >>> >>> [frankcox at mutt ~]$ strace -p 5401 >>> strace: Process 5401 attached >>> select(11, [5 9 10], [], NULL, NULL >>> >>> Then it just sits there with no further action. I get my cursor back >>> when I hit ctrl-c. >>> >>> [frankcox at mutt ~]$ strace -p 5400 >>> strace: Process 5400 attached >>> restart_syscall(<... resuming interrupted nanosleep ...>) = 0 >>> wait4(5401, 0x7ffd45105564, WNOHANG, NULL) = 0 >>> nanosleep({tv_sec=0, tv_nsec=20000000}, NULL) = 0 >>> wait4(5401, 0x7ffd45105564, WNOHANG, NULL) = 0 >>> nanosleep({tv_sec=0, tv_nsec=20000000}, NULL) = 0 >>> wait4(5401, 0x7ffd45105564, WNOHANG, NULL) = 0 >>> nanosleep({tv_sec=0, tv_nsec=20000000}, NULL) = 0 >>> wait4(5401, 0x7ffd45105564, WNOHANG, NULL) = 0 >>> nanosleep({tv_sec=0, tv_nsec=20000000}, NULL) = 0 >>> wait4(5401, 0x7ffd45105564, WNOHANG, NULL) = 0 >>> nanosleep({tv_sec=0, tv_nsec=20000000}, NULL) = 0 >>> wait4(5401, 0x7ffd45105564, WNOHANG, NULL) = 0 >>> nanosleep({tv_sec=0, tv_nsec=20000000}, NULL) = 0 >>> wait4(5401, 0x7ffd45105564, WNOHANG, NULL) = 0 >>> >>> The wait4-etc line just keeps repeating endlessly until I hit ctrl-c. >>> >>> Unfortunately, I have no idea what any of the above actually means. >>> Does it tell us anything interesting? >> >> Yay! I am glad someone else on the planet is experiencing this. >> I noticed this started happening to me after updating some CentOS Linux > 8 >> systems today. >> >> I discovered if I set ForwardX11=no (either on ssh command line or in > ~/.ssh/config) the hang does not happen. But why does that matter? No > updates to openssh. >> >> It is not the systemd update doing something silly with session >> management. I painfully downgraded manually and rebooted to no effect. > >> As an aside, why can't we we have nice things in life like 'dnf >> downgrade >> systemd\*' actually work? I did the below - might be dumb, but it > worked -- alternate suggestions to downgrade are appreciated - searching > the list and my google-fu was off the mark today. >> >> cd [path-to-repo]/centos/8/BaseOS/x86_64/os/Packages >> dnf downgrade $(rpm -qa systemd\* | grep 239-41.el8_3.2 | sed -e > 's/3\.2/3.1/' -e 's/^/.\//' -e 's/$/.rpm/') >> >> Chris > > > [adjusted the subject, hope that is OK.] > > Found it! It's the dbus update to 1.12.8-12. Downgrade to -11 > and ssh connections close normally. > > To clarify the problem, with the new dbus, simple ssh's like: > > ssh somehost uptime > > will print the uptime, but do not return to the local shell prompt until > you hit ctrl-c. It works normally if you downgrade dbus or > > ssh -o forwardx11=no somehost uptime > > I'm sure a bug report exists somewhere, but that's something to dig for or > create tomorrow. > > To downgrade, packages were scattered in different locations, so I copied > them to one directory and did > > dnf downgrade ./* > > The packages I needed to downgrade on a x86_64 system were: > > dbus-1.12.8-11.el8.x86_64.rpm > dbus-common-1.12.8-11.el8.noarch.rpm > dbus-daemon-1.12.8-11.el8.x86_64.rpm > dbus-devel-1.12.8-11.el8.x86_64.rpm > dbus-libs-1.12.8-11.el8.x86_64.rpm > dbus-tools-1.12.8-11.el8.x86_64.rpm > dbus-x11-1.12.8-11.el8.x86_64.rpm Now that's really interesting, I was wondering why I don't see this on OL8. The thing is that certain OL8 packages have an additional RPM revision added like .0.1. Just checked dbus and its changelog shows: * Tue Feb 16 2021 Kevin Lyons <kevin.x.lyons at oracle.com> -1.12.8-12.0.1 - bus: raise fd limits before dropping privs [Orabug: 31175643] - fix netlink poll: error 4 (Zhenzhong Duan) So OL is defnitly not 100% bug to bug compatible like the other clones :-) And it makes me a bit worried why O* fixed this on Feb 16 and the broken dbus packages are now (in April) installed on CentOS servers? Regards, Simon