I got the following oops after doing "modprobe uhci". The system froze completely about 30 seconds after that. Before that, I have unloaded uhci, loaded usb-uhci, and then unloaded usb-uhci again. This could be relevant. Please contact me if you need more information. --J. ksymoops 2.4.5 on i686 2.4.21. Options used -V (default) -k /proc/ksyms (default) -l /proc/modules (default) -o /lib/modules/2.4.21/ (default) -m /boot/bzI-2.4.21-a20030523s10p12l.map (specified) Jun 28 03:20:20 tnuctip kernel: kernel BUG at slab.c:815! Jun 28 03:20:20 tnuctip kernel: invalid operand: 0000 Jun 28 03:20:20 tnuctip kernel: CPU: 0 Jun 28 03:20:20 tnuctip kernel: EIP: 0010:[] Tainted: PF Using defaults from ksymoops -t elf32-i386 -a i386 Jun 28 03:20:20 tnuctip kernel: EFLAGS: 00010246 Jun 28 03:20:20 tnuctip kernel: eax: 00000000 ebx: c12c7bb0 ecx: c12c7c18 edx: c12c7ba8 Jun 28 03:20:20 tnuctip kernel: esi: c12c7ba2 edi: d083bd1a ebp: 0000003c esp: ce159eec Jun 28 03:20:20 tnuctip kernel: ds: 0018 es: 0018 ss: 0018 Jun 28 03:20:20 tnuctip kernel: Process modprobe (pid: 19676, stackpage=ce159000) Jun 28 03:20:20 tnuctip kernel: Stack: fffffff4 00000001 d0836000 00006b90 ce159f08 c12c7bd0 00000004 0000001c Jun 28 03:20:20 tnuctip kernel: d083a7c0 d083bd0c 0000003c 00000020 00020000 00000000 00000000 00000001 Jun 28 03:20:20 tnuctip kernel: c0117361 ce158000 00000000 00000013 bfffc178 d0836000 00005d48 c2d4b000 Jun 28 03:20:20 tnuctip kernel: Call Trace: [] [] [] [] [] Jun 28 03:20:20 tnuctip kernel: Code: 0f 0b 2f 03 40 8a 24 c0 8b 12 8b 02 0f 18 00 81 fa 08 ae 28 >>EIP; c013267d <===== >>ebx; c12c7bb0 <_end+fca3d8/1050c888> >>ecx; c12c7c18 <_end+fca440/1050c888> >>edx; c12c7ba8 <_end+fca3d0/1050c888> >>esi; c12c7ba2 <_end+fca3ca/1050c888> >>edi; d083bd1a <[mousedev].bss.end+7a63/42da9> >>esp; ce159eec <_end+de5c714/1050c888> Trace; d083a7c0 <[mousedev].bss.end+6509/42da9> Trace; d083bd0c <[mousedev].bss.end+7a55/42da9> Trace; c0117361 Trace; d0836060 <[mousedev].bss.end+1da9/42da9> Trace; c01086df Code; c013267d 00000000 <_EIP>: Code; c013267d <===== 0: 0f 0b ud2a <===== Code; c013267f 2: 2f das Code; c0132680 3: 03 40 8a add 0xffffff8a(%eax),%eax Code; c0132683 6: 24 c0 and $0xc0,%al Code; c0132685 8: 8b 12 mov (%edx),%edx Code; c0132687 a: 8b 02 mov (%edx),%eax Code; c0132689 c: 0f 18 00 prefetchnta (%eax) Code; c013268c f: 81 fa 08 ae 28 00 cmp $0x28ae08,%edx