Plug in 3G mobile broadband USB device and nm-applet zooms to 100% CPU

[Andrew Cowie]

Running Ubuntu Karmic. an update to either HAL, NetworkManager, or nm-applet in the last 48 hours has caused network manager to flail when a 3G mobile broadband USB device is inserted.

The behaviour is very strange. Sometimes it works when first plugged in after a fresh boot, but subsequently inserting the device the nm-applet "connecting" indicator spins at something approaching lightspeed, and the CPU is pegged 100%.

The NetworkManager process shows up as the thing eating the processor; tried killing it, but it's respawned replacement shortly resumes 100% CPU consumption and mad spinning.

I've had one success by killing the demon AND the applet then restarting [the latter], but in the main I've had to reboot to fix it; I had to find an open wifi access point to report this. The whole stack was running fine until Saturday.

AfC

[Andrew Cowie (afcowie)]

It is possible that this is related to the "Available to all users" checkbox in the Edit Connections... -> Mobile Broadband -> Edit $connection dialog.

When that was first checked, I had to escallate to root priviledges, (presumably so the NetworkManager demon could be instructed); susequent attempts to edit the connection resulted in an error dialog, something to do with authentication or permissions lacking. Anyway, at that point, trying to delete the connection, start over, etc, reconnecting the device pegged the CPU at 100%.

AfC

[itsjustarumour (itsjustarumour-gmail-deactivatedaccount-deactivatedaccount)]

Confirming still getting this in Karmic 9.10 Final (32-bit), on both my laptop and Desktop PC. Using A Huiwei E172 3G USBstick, on Vodafone. This same 3G stick worked fine on both these machines in Jaunty 9.04.

[itsjustarumour (itsjustarumour-gmail-deactivatedaccount-deactivatedaccount)]

OK, I have a bit more time on my hands than when I first looked at this bug, so I'll provide the proper amount of information in the hope someone will be able to look at this :)

Technical details:

Distro Version - Ubuntu Karmic 9.10, 32-bit, default fresh install with latest updates
Desktop Environment - GNOME 2.28.1 (Ubuntu 2009-11-03)
Kernel - Linux 2.6.31-19-generic
System - Athlon 64 3400 2.2GHz processor, NVidia 6800LE graphics, 1.5MB RAM
Network Manager Applet Version - 0.7.996
Modem - Huawei E172 USB stick on Vodafone with latest firmware

Steps to reproduce bug:

1. Fresh install of Karmic 9.10.
2. Insert Huawei E172 3G USB Modem
3. Left-click on NM-Applet icon in system tray.
4. Select "New Mobile Broadband (GSM) connection..."
5. Go through wizard entering settings as required, then click "Apply".
6. Network-manager successfully connects to the Internet.
7. Right-click on NM-Applet icon in system tray.
8. Select "Edit Connections".
9. Click on "Mobile Broadband" tab.
10. Highlight the connection (in my case "Vodafone Contract").
11. Click on "Edit".
12. "Allow application access to keyring" box appears. Click on "Always Allow".
13. "Editing Vodafone Contract" box appears.
14. Put a tick in the checkbox for "Connect automatically" at the top, and another tick in the checkbox for "Available to all users" at the bottom. Then click on "Apply".
15. "Authenticate. System policy prevents modification of system settings" box appears. Enter password and hit "Authenticate".
16. Click "Close" in the "Network Connections" dialogue box.
17. Log off machine, then log back in.
18. Icon on NM-Applet in system immediately start spinning round very very quickly, and CPU usage goes up to 100%.
19. The only way to stop this is to delete the 3G connection completely, and then start again from fresh by running the wizard again.

What should happen:

Network-Manager should allow 3G connection with Huawei E172 modem to be "Available To All Users".
Network-Manager should not eat 100% of CPU.

If you need any further information or the contents of any log files, please let me know.

Best Regards,

itsjustarumour