Most recent kernel where this bug did not occur: unknown
Distribution: Slackware 12.0

Hardware Environment: HUAWEI E220 USB modem
lspci -- only relevant info included
00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and 945GT Express Memory Controller Hub (rev 03)
00:01.0 PCI bridge: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and 945GT Express PCI Express Root Port (rev 03)
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 02)
00:1c.0 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 1 (rev 02)
00:1c.1 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 2 (rev 02)
00:1c.2 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 3 (rev 02)
00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #1 (rev 02)
00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #2 (rev 02)
00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #3 (rev 02)
00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #4 (rev 02)
00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2 EHCI Controller (rev 02)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e2)

Software Environment:
sh scripts/ver_linux
If some fields are empty or look unusual you may have an old version.
Compare to the current minimal requirements in Documentation/Changes.

Linux host94 2.6.23 #1 SMP Fri Oct 12 17:42:37 GMT 2007 i686 Intel(R) Core(TM)2 CPU         T5300  @ 1.73GHz GenuineIntel GNU/Linux

Gnu C                  4.1.2
Gnu make               3.81
binutils               Binutils
util-linux             2.12r
mount                  2.12r
module-init-tools      3.2.2
e2fsprogs              1.39
pcmciautils            014
quota-tools            3.13.
PPP                    2.4.4
Linux C Library        2.5
Dynamic linker (ldd)   2.5
Linux C++ Library      6.0.8
Procps                 3.2.7
Net-tools              1.60
Kbd                    1.12
oprofile               0.9.2
Sh-utils               6.9
udev                   111
wireless-tools         28
Modules Loaded         ppp_deflate bsd_comp ppp_async tifm_sd snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss usb_storage option capability commoncap ppp_generic slhc usbserial pcspkr psmouse pcmcia snd_hda_intel snd_pcm ehci_hcd snd_timer snd_page_alloc snd_hwdep iwl3945 yenta_socket snd rsrc_nonstatic tifm_7xx1 pcmcia_core tifm_core mac80211 sdhci video uhci_hcd soundcore output

cat /proc/modules -- again, only relevant parts
ppp_deflate 4544 0 - Live 0xf8c86000
ppp_async 8192 1 - Live 0xf8bf8000
usb_storage 32256 0 - Live 0xf8c59000
option 8640 0 - Live 0xf8bf4000
ppp_generic 17172 7 ppp_deflate,bsd_comp,ppp_async, Live 0xf8c45000
slhc 5376 1 ppp_generic, Live 0xf8bce000
usbserial 25832 5 option, Live 0xf8c3d000
ehci_hcd 26828 0 - Live 0xf8be0000
sdhci 13964 0 - Live 0xf8875000
uhci_hcd 19404 0 - Live 0xf8868000

Problem Description: With the USB modem connected and hard at work, the entire system freezes randomly. Checking dmesg does not reveal any clues. 

Steps to reproduce: unknown