On 05/17/2013 07:29 AM, Adam Williamson wrote:
This is a weird bug I've seen 3 or 4 times since upgrading to
F19, and
am having trouble pinning down.
Occasionally, after my session has been up for some time, runs of 'su'
start behaving oddly. After I enter the root password, it takes a long
time - longer than the delay that's always happened when you fat-finger
your password, even - before it succeeds. Usually, of course, it's
instant. But when this bug happens, I just get to sit there while it
thinks about it for like 10-15 seconds before I eventually get a root
prompt.
This only applies to my desktop session - but it applies to any terminal
running in the desktop. At least, it applies to gnome-terminal (even if
closed and opened again) and xterm. But if I go to ctrl-alt-f2, login,
and run an 'su', that still returns instantly.
I've tried strace'ing su, but interestingly, I can't get it to work:
running su via strace always seems to result in "Authentication
failure" (which doesn't display this bug; it's only _normally_ slow, the
same slowness that has always been the case when you fail the password).
So I'm kinda stuck, really. Has anyone else seen this? Any bright ideas
for debugging it? Thanks!
Just a guess, but is your shell a subprocess of sssd? I have no idea if that
might have any influence. But, I noticed, that on my machine, all of my bash
processes are spawned via sssd, even though I didn't configure or even enable
it. If that or anything similar happened in your case, I wouldn't be surprised
that your shell is waiting for some timeouts while doing authentication that you
might not know about. Again, that's just a wild guess.
--
Jan Synacek
Software Engineer, Red Hat