Red Hat Bugzilla – Bug 529711
qemu: could not open serial device 'pty'
Last modified: 2015-10-25 21:06:47 EDT
Description of problem:
When I try to start a x86_64 KVM guest on my box I obtain this backtrace from virt-manager:
Traceback (most recent call last):
File "/usr/share/virt-manager/virtManager/engine.py", line 571, in run_domain
File "/usr/share/virt-manager/virtManager/domain.py", line 664, in startup
File "/usr/lib64/python2.6/site-packages/libvirt.py", line 293, in create
if ret == -1: raise libvirtError ('virDomainCreate() failed', dom=self)
libvirtError: internal error unable to start guest: qemu: could not open serial device 'pty': No child processes
Oct 19 17:43:27 gvarisco libvirtd: 17:43:27.967: error : qemudReadLogOutput:915 : internal error Process exited while reading console log output
Oct 19 17:43:27 gvarisco libvirtd: 17:43:27.967: error : qemudWaitForMonitor:1203 : internal error unable to start guest: qemu: could not open serial device 'pty': No child processes#012
How can I fix this issue?
Please let me know if you need further details.
Version-Release number of selected component (if applicable):
It's better to put your system info here, like CPU.
Besides, you may use "selinuxenabled ; echo $?" to check if selinux is enabled. Status 0 means selinux is enabled, otherwise not.
I have exact the same error after an update yesterday. Before this update F12Beta - released yesterday! :-) - was running fine.
1. My smolt profile can be found here 
2. I'm running selinux in permissive mode, so I get AVC-messages. Actually I get tree messages, see 
 BZ: #530189, #530191, and #530192
Hope this info helps.
Danial Walsh has responded on bug report: #530192: He said:
"This is a leaked file descriptor from qemu which should be changed.
But the error is caused by a bad entry in your /etc/fstab, that was introduced
Your /etc/fstab devpts line should look like
grep devpts /etc/fstab
devpts /dev/pts devpts gid=5,mode=620 0 0
Otherwise svirt through glibc will attempt to fix the labeling of the pty.
Fixing this and executing mount -a should fix the problem."
This also fixed the original issue.
Thanks for the hints Martin
Gianluca, could you check your devpts entry in /etc/fstab?
Mark, I confirm Martin's hint fixed my issue related to devpts.
Many thanks to both of you! ;-)
*** This bug has been marked as a duplicate of bug 515521 ***