Description of problem:
There is really no "button" on my machine to be handled by ACPI
and 'lsmod' shows usage 0.  Still 'rmmod button' ends up with
the following oops:

kernel BUG at fs/proc/generic.c:660!
invalid operand: 0000 [#1]
SMP 
CPU:    0
EIP:    0060:[<0218f128>]    Not tainted
EFLAGS: 00010202   (2.6.4-1.305smp) 
EIP is at remove_proc_entry+0xa6/0xf6
eax: 21ecc4b0   ebx: 228615f5   ecx: 00000000   edx: 21ecc4b0
esi: 21ecc4b0   edi: 20e82d80   ebp: 00000006   esp: 1ede3f50
ds: 007b   es: 007b   ss: 0068
Process rmmod (pid: 1218, threadinfo=1ede3000 task=1ee68670)
Stack: 21ecc480 228615f5 22861f80 02314b38 00000000 1ede3000 228614b2
0213817d 
       00000000 74747562 21006e6f 21015380 f70cb000 02150345 21ee7e00
f70cc000 
       021507f3 210153bc 1ed6a140 1f776080 00000246 21015380 1ede3fc0
00000004 
Call Trace:
 [<228614b2>] acpi_button_exit+0x1a/0x1b [button]
 [<0213817d>] sys_delete_module+0x115/0x157
 [<02150345>] unmap_vma_list+0xe/0x17
 [<021507f3>] do_munmap+0x17e/0x18a
 [<0211c220>] do_page_fault+0x0/0x4b0

Code: 0f 0b 94 02 3a de 2d 02 8b 47 40 85 c0 75 09 89 f8 e8 0c ff 

This is ACPI information from dmesg:

ACPI: S3 and PAE do not like each other for now, S3 disabled.
ACPI: RSDP (v000 PTLTD                                     ) @ 0x000f7190
ACPI: RSDT (v001 PTLTD    RSDT   0x06040000  LTP 0x00000000) @ 0x1fefd123
ACPI: FADT (v001 AMD    TECATE   0x06040000 PTL  0x000f4240) @ 0x1fefef2e
ACPI: MADT (v001 PTLTD  	 APIC   0x06040000  LTP 0x00000000) @
0x1fefefa2ACPI: DSDT (v001    AMD  AMDACPI 0x06040000 MSFT 0x0100000d)
@ 0x00000000
ACPI: PM-Timer IO Port: 0x8008
ACPI: Local APIC address 0xfee00000
ACPI: LAPIC (acpi_id[0x00] lapic_id[0x01] enabled)
ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] enabled)
ACPI: LAPIC_NMI (acpi_id[0x00] high edge lint[0x1])
ACPI: LAPIC_NMI (acpi_id[0x01] high edge lint[0x1])
ACPI: IOAPIC (id[0x02] address[0xfec00000] global_irq_base[0x0])
ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 high edge)
Using ACPI (MADT) for SMP configuration information
ACPI: Subsystem revision 20040326
ACPI: Interpreter enabled
ACPI: Using IOAPIC for interrupt routing
ACPI: PCI Root Bridge [PCI0] (00:00)
ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT]
ACPI: PCI Interrupt Routing Table [\_SB_.PCI0.AGP_._PRT]
ACPI: PCI Interrupt Routing Table [\_SB_.PCI0.OP2P._PRT]
ACPI: PCI Interrupt Link [LNKA] (IRQs 3 5 *10 11)
ACPI: PCI Interrupt Link [LNKB] (IRQs 3 5 10 11)
ACPI: PCI Interrupt Link [LNKC] (IRQs 3 5 *10 11)
ACPI: PCI Interrupt Link [LNKD] (IRQs 3 *5 10 11)

Yes, I know; "don't do it then".  Still oops is not that nice.

Version-Release number of selected component (if applicable):
kernel 2.6.4-1.305smp

How reproducible:
100%