Login timed out after waking from suspend

Bug #1300462 reported by Christopher Barrington-Leigh on 2014-03-31
16
This bug affects 3 people
Affects Status Importance Assigned to Milestone
fprintd
Won't Fix
Medium
lightdm (Ubuntu)
Undecided
Unassigned

Bug Description

I'm using fprint package for finger-print authentication.

Half the time when my laptop recovers from suspend, I am able to enter a password (or, after pressing Enter, a finger print instead).
But half the time when it recovers from suspend, the lightdm (?) login screen instead says that authentication has timed out. For some reason I then have to wait a good 25 seconds before I get another chance. At that point, I am able to enter a password or fingerprint as normal.

This "time out" should not be triggered during/after a suspend.
Also, if there is a time out for some reason, it should just wait the normal 2 seconds required after entering an incorrect password.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: lightdm 1.9.13-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-20.42-generic 3.13.7
Uname: Linux 3.13.0-20-generic x86_64
ApportVersion: 2.14-0ubuntu1
Architecture: amd64
CurrentDesktop: Unity
Date: Mon Mar 31 17:29:11 2014
EcryptfsInUse: Yes
InstallationDate: Installed on 2014-03-11 (20 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Alpha amd64 (20140218)
SourcePackage: lightdm
UpgradeStatus: No upgrade log present (probably fresh install)

When this problem occurs (most of the time), the machine wakes without the fingerprint sensor activated (no light), but the login gui screen prompt says something like "swipe your finger". It very quickly gives up, and then says Authentication Timed Out and makes me wait a LONG time. Note that during this time, no other users are listed on the lightdm login screen, so I cannot click on another user or guest to log in.

so maybe the problem is something to do with the fingerprint package, fprint ?

I'm using fprint package for finger-print authentication on Ubuntu 14.04.
It's working perfectly for most things.

Some of the time when my laptop recovers from suspend, I am able to enter a password (or, after pressing Enter, a finger print instead).
But much of the time when it recovers from suspend, the lightdm (?) login screen instead says that authentication has timed out. For some reason I then have to wait a good 25 seconds before I get another chance. At that point, I am able to enter a password or fingerprint as normal.

When this problem occurs (most of the time), the machine wakes without the fingerprint sensor activated (no light), but the login gui screen prompt says something like "swipe your finger". It very quickly gives up, and then says Authentication Timed Out and makes me wait a LONG time. Note that during this time, no other users are listed on the lightdm login screen, so I cannot click on another user or guest to log in.

This "time out" should not be triggered during/after a suspend.
Also, if there is a time out for some reason, it should just wait the normal 2 seconds required after entering an incorrect password.

I'm posting this here because it seems to be the fact that the fingerprint scanner is somehow unavailable after waking, and maybe it is fprintd that times out the authentication for so long.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: lightdm 1.9.13-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-20.42-generic 3.13.7
Uname: Linux 3.13.0-20-generic x86_64
ApportVersion: 2.14-0ubuntu1
Architecture: amd64
CurrentDesktop: Unity
Date: Mon Mar 31 17:29:11 2014
EcryptfsInUse: Yes
InstallationDate: Installed on 2014-03-11 (20 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Alpha amd64 (20140218)
SourcePackage: lightdm
UpgradeStatus: No upgrade log present (probably fresh install)

I have submitted this bug: https://bugs.freedesktop.org/show_bug.cgi?id=77110 and tried to link it to the affected packages section here on launchpad.

Changed in fprintd:
importance: Undecided → Unknown
status: New → Unknown
Changed in fprintd:
importance: Unknown → Medium
status: Unknown → Confirmed

That's unlikely to be an fprintd bug. Please try and debug this on the LightDM side with your distribution first, and file a bug here when you have a reproducer.

Seems to me that LightDM is using a single PAM conversation for both pam_fprintd and the normal password checks. This isn't something that we can fix in pam_fprintd, and LightDM will have to work-around the PAM limitations.

Reopen the bug when you've debugged the LightDM side of things.

Changed in fprintd:
status: Confirmed → Won't Fix

This problem continues to be embarrassing under 14.04
My evidence for it being a fprintd bug is that the one thing I can do while it is "hung" being timed out is to switch to another user (top right menu). If I do that, the login skips fingerprint access (but password login works okay) until the same amount of time as if I'd waited to log in as myself. That is, if I give it enough time, the fingerprint reader seems to be available for another user, as well, but before that timeout, the rest of the lightdm seems to be working.

Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in lightdm (Ubuntu):
status: New → Confirmed

This problem continues to plague me on the upcoming Ubuntu release 15.04.

I do not understand your instructions, or maybe am not qualified. How do I "debug the LightDM side of things"?

File a bug against LightDM and let the LightDM developers fix it, if they can.

This problem exists still in 15.04. If this is a lightdm problem, what should be done next?

Thank you very much. I think it's been listed against LightDM on the Ubuntu bug site since (near) the beginning. So it's just that it hasn't caught their attention yet, I suppose. Or maybe it needs another upstream link out of Ubuntu.
Thanks!

I believe this problem may have resolved itself, just recently, with 15.04 updates. It used to occur most of the time, and very recently it hasn't at all.

... to follow up: in fact, it has not resolved itself in the 15.04 release. Often, things work better in that as soon as the machine waits up, it is waiting for a fingerprint scan. However, the rest of the time, it hangs for a tens of seconds with the "authentication has timed out" error message, and then solicits a password, and only then (after something incorrect has been entered) solicits a fingerprint reading.

c

To post a comment you must log in.
This report contains Public information  Edit
Everyone can see this information.

Other bug subscribers

Remote bug watches

Bug watches keep track of this bug in other bug trackers.