this time I managed to get a register dump. the crash is ISDN related.
------------------------------------------------------------------------------
general protection: 0000
CPU: 0
EIP: 0010:[<0285dbde>]
EFLAGS: 00010086
eax: 00000007 ebx: 00247918 ecx: cd641400 edx: 00000018
esi: 20000000 edi: 01cd6c0c ebp: 00000019 esp: 001ad5d4
ds: 0018 es: 0018 fs: 002b gs: 0018 ss: 0018
Process swapper (pid: 0, process nr: 0, stackpage=001ab8bc)
Stack: 00247918 20000000 00000007 00000019 746e6576 5f564520 555f324c 00000a49
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 ffffffff 00000004 ffffffff
Call Trace: [<00184e45>] [<0010f048>] [<0010c6fd>] [<0010b405>] [<0010c74a>] [<0010bba9>] [<001122e3>]
[<02850000>] [<0010a851>] [<0285f2ae>] [<02860018>] [<0010ae10>] [<0010ade8>] [<0010a69d>] [<0285f2ae>]
[<02864e0f>] [<00110b38>] [<00110b70>] [<0285f3fa>] [<001105f8>] [<0011628b>] [<0010ff86>] [<00109664>]
[<00109674>] [<0010a512>] [<00109360>] [<001091eb>]
Code: 8a 89 e0 01 00 00 88 8c 24 d4 00 00 00 eb 14 90 90 90 66 8b
Aiee, killing interrupt handler
kfree of non-kmalloced memory: 001ad904, next= 00000000, order=38444
kfree of non-kmalloced memory: 001ad8f4, next= 00000000, order=38444
kfree of non-kmalloced memory: 001ade08, next= 00000000, order=38444
idle task may not sleep
idle task may not sleep
idle task may not sleep
idle task may not sleep
idle task may not sleep
Using `System.map' to map addresses to symbols.
>>EIP: 285dbde <ippp_table+273a/6960>
Trace: 184e45 <clear_selection+d/48>
Trace: 10f048 <pentium_timer_interrupt+18/8c>
Trace: 10c6fd <do_IRQ+2d/50>
Trace: 10b405 <fast_IRQ0_interrupt+55/80>
Trace: 10c74a <do_fast_IRQ+2a/4c>
Trace: 10bba9 <fast_IRQ7_interrupt+39/60>
Trace: 1122e3 <printk+117/130>
Trace: 2850000 <isdn_net_log_packet+208/b6ac>
Trace: 10a851 <die_if_kernel+65/2c0>
Trace: 285f2ae <ippp_table+3e0a/6960>
Trace: 2860018 <ippp_table+4b74/6960>
Trace: 10ae10 <do_general_protection+28/54>
Trace: 10ae10 <do_general_protection+28/54>
Trace: 10a69d <error_code+3d/50>
Trace: 285f2ae <ippp_table+3e0a/6960>
Trace: 2864e0f <2863004+300b/5200>
Trace: 110b38 <timer_bh+b8/14c>
Trace: 110b70 <timer_bh+f0/14c>
Trace: 285f3fa <ippp_table+3f56/6960>
Trace: 1105f8 <immediate_bh+28/38>
Trace: 11628b <do_bottom_half+3b/60>
Trace: 10ff86 <schedule+3a/288>
Trace: 109664 <sys_idle+5c/70>
Trace: 109674 <sys_idle+6c/70>
Trace: 10a512 <system_call+52/80>
Trace: 109360 <init>
Trace: 1091eb <start_kernel+177/184>
Code: 285dbde <ippp_table+273a/6960> movb 0x1e0(%ecx),%cl
Code: 285dbe4 <ippp_table+2740/6960> movb %cl,0xd4(%esp,1)
Code: 285dbeb <ippp_table+2747/6960> jmp 285dc01 <ippp_table+275d/6960>
Code: 285dbed <ippp_table+2749/6960> nop
Code: 285dbee <ippp_table+274a/6960> nop
Code: 285dbef <ippp_table+274b/6960> nop
Code: 285dbf0 <ippp_table+274c/6960> movw (%eax),%ax
Code: 285dbf3 <ippp_table+274f/6960> nop
Code: 285dbf4 <ippp_table+2750/6960> nop