Launchpad has imported 8 comments from the remote bug at http://bugzilla.openvz.org/show_bug.cgi?id=1812.
If you reply to an imported comment from within Launchpad, your comment will be sent to the remote bug automatically. Read more about Launchpad's inter-bugtracker facilities at https://help.launchpad.net/InterBugTracking. ------------------------------------------------------------------------ On 2011-03-15T09:45:10+00:00 Michaelk wrote: Created attachment 1429 strace sessions of vzctl enter Hi! Problem: When running "vzctl enter <VEID>" the command will hang with latest version of bash i.e 4.2.7 ( happens with all 4.2.x versions ) I first thought this was bash bug and filed a report to the maintainer of bash (Chet Ramey) but got back the response below which indicates this might be a bug in vzctl instead, Let me know if you need any more information. There is also a thread discussing this issue at: https://groups.google.com/group/gnu.bash.bug https://groups.google.com/group/gnu.bash.bug/browse_thread/thread/0be5df8f41c8b88c# //Michael > Hi Chet! > > I run 3 different strace sessions (see attached file) > > 1. A working session (bash 3.2.25) > > # strace -ff -o /tmp/bash_strace/bash_working/bash_working.log vzctl enter 152 > > 2. A failing session (bash 4.2.7): > > # strace -ff -o /tmp/bash_strace/bash_not_working/bash_not_working.log > vzctl enter 152 > > for the failing session pstree shows: > > bash(23067)---strace(23230)---vzctl(23231)---vzctl(23232)---bash(23233) I suspect this is a bug in vzctl that was masked by bash-4.1 and previous versions. The only change of any significance here is that bash-4.1 closed file descriptors 3-20 at startup. That's a bug; you can't close fds out from under libraries like that. This caused mysterious crashes on Mac OS X, for example when running bash as a login shell under iTerm. Bash-4.2 sets the fds to close-on-exec instead. The problem is that vzctl plays fast and loose with file descriptors. It leaves read and write ends of pipes open in the child process it forks to exec bash when it uses the other ends internally to communicate with that child through the pty it opens as the controlling terminal. The big difference between the non-working and working versions is that bash-4.2 inherits file descriptors 3, 7, 9, and 10 and leaves them open, where bash-4.1 closed them. This results in the the process group that bash-4.2 is using being orphaned, which makes read() return EOF and the kernel send SIGHUP and SIGCONT to bash. This is consistent with the strace output. You can test this by changing shell.c to call close(i) instead of SET_CLOSE_ON_EXEC(i) around like 541. That's just to prove vzctl has a bug, however -- I'm not going to revert that change. Keep in mind that I haven't looked at the vzctl source code, and so don't have any patches for it. Somehow, though, the file descriptors that get closed in process 23231 after forking 23232 (in the bash-not-working set of traces, fds 3,7,9,10) need to get closed in 23233 after 23232 forks it and before it execs bash. Let me know how it goes. If you can make the right changes to vzctl and that fixes the problem, so much the better. Reply at: https://bugs.launchpad.net/openvz-tools/+bug/732322/comments/1 ------------------------------------------------------------------------ On 2011-03-16T09:33:09+00:00 Openvz-bugs wrote: I've raised the severity because when an owner of a virtual machine installs Bash 4.2 patchlevel 0 or higher, it is a DoS against the owner of the physical machine :-). There are times when it is handy to have the vzctl enter option and this bug closes that route. Reply at: https://bugs.launchpad.net/openvz-tools/+bug/732322/comments/2 ------------------------------------------------------------------------ On 2011-03-16T15:29:23+00:00 Kir Kolyshkin wrote: Guys, Fix committed into GIT, lightly tested here, works fine for me. Can you please test it as well? http://git- ovzcore.sw.ru/?p=vzctl;a=commit;h=e7c40ee697606e43d6242fd3c124e370588ae26f Will be available in vzctl-3.0.27 (and most probably in vzctl-3.0.26.2, too). Reply at: https://bugs.launchpad.net/openvz-tools/+bug/732322/comments/3 ------------------------------------------------------------------------ On 2011-03-16T18:02:18+00:00 Openvz-bugs wrote: I've just tested the patch and checked if it works: hoefnix2:~# vzctl enter 60 entered into CT 60 ve60:/# pacman -Q bash bash 4.2.008-1 I hope this speaks for itself :-). Thanks for the quick patch! Reply at: https://bugs.launchpad.net/openvz-tools/+bug/732322/comments/4 ------------------------------------------------------------------------ On 2011-03-17T16:03:27+00:00 Kir Kolyshkin wrote: Is that ArchLinux that comes with bash-4.2? Are you aware of any other distros already using it? I mean, I am trying to assess does it makes sense to release vzctl-3.0.36.2 immediately, or can it wait (will I have some more fixes)? Reply at: https://bugs.launchpad.net/openvz-tools/+bug/732322/comments/5 ------------------------------------------------------------------------ On 2011-03-17T20:44:29+00:00 Yettyn wrote: (In reply to comment #4) > Is that ArchLinux that comes with bash-4.2? Are you aware of any other distros > already using it? I mean, I am trying to assess does it makes sense to release > vzctl-3.0.36.2 immediately, or can it wait (will I have some more fixes)? Gentoo also provides it and yes I (and other Gentoo users) would very much need vzctl-3.0.36.2, thank you. Reply at: https://bugs.launchpad.net/openvz-tools/+bug/732322/comments/6 ------------------------------------------------------------------------ On 2011-03-18T08:26:12+00:00 Openvz-bugs wrote: I'm indeed using Arch Linux for my servers because it is easier to upgrade with small changes than once per two year with very big changes :-). If I had to make the decission, I probbably would wait. People who use bleeding edge like Arch Linux -- and there I'm probably one of few who uses this distribution -- or Gentoo will find the solution in this bugfix. So I don't see a big hurry. I raised the importance because there was no solution and could raise on DoS against the owner of the physical machine. It has nothing to do with the importance of a new version of vzctl :-). Reply at: https://bugs.launchpad.net/openvz-tools/+bug/732322/comments/7 ------------------------------------------------------------------------ On 2011-03-18T21:45:36+00:00 Kir Kolyshkin wrote: Too late, vzctl 3.0.26.2 released :) http://openvz.org/pipermail/announce/2011-March/000200.html http://wiki.openvz.org/Download/vzctl/3.0.26.2 Reply at: https://bugs.launchpad.net/openvz-tools/+bug/732322/comments/8 ** Changed in: openvz-tools Status: Unknown => Fix Released ** Changed in: openvz-tools Importance: Unknown => High -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/732322 Title: after upgrading to 4.2 bash stopped working inside a OpenVZ container To manage notifications about this bug go to: https://bugs.launchpad.net/openvz-tools/+bug/732322/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
