Pentium III 800MHz 512MB ram
CM8738 sound card

on 2.6.12-rc5-mm1 on gentoo-linux 
play sound through alsa, then quit program. I get an oops:

Unable to handle kernel NULL pointer dereference at virtual address 000000a4
 printing eip:
c02acb79
*pde = 00000000
Oops: 0002 [#1]
PREEMPT
Modules linked in:
CPU:    0
EIP:    0060:[<c02acb79>]    Not tainted VLI
EFLAGS: 00210286   (2.6.12-rc5-mm1-personal)
EIP is at snd_pcm_mmap_data_close+0xa/0x11
eax: 00000000   ebx: db194000   ecx: d9fc8720   edx: d9f24b40
esi: dfabd080   edi: d9f24b18   ebp: df461b80   esp: db195f58
ds: 007b   es: 007b   ss: 0068
Process mplayer (pid: 14876, threadinfo=db194000 task=df382540)
Stack: c013dd8c d9f24b18 00000000 df461b80 b653d000 c013f1d5 d9f24b18 d9f24b18
       d9f24b18 b6545000 c013f4ec df461b80 d9f24b18 d9fc8858 df461b80 df461bb0
       00008000 db194000 c013f529 df461b80 b653d000 00008000 b653d000 00008000
Call Trace:
 [<c013dd8c>] remove_vm_struct+0x49/0x6f
 [<c013f1d5>] unmap_vma_list+0x14/0x1f
 [<c013f4ec>] do_munmap+0xe7/0xf3
 [<c013f529>] sys_munmap+0x31/0x4b
 [<c0102bd7>] sysenter_past_esp+0x54/0x75
Code: 8b 54 24 04 81 48 14 00 00 08 00 c7 40 44 fc c6 38 c0 89 50 50 8b 42 60 ff
80 a4 00 00 00 31 c0 c3 8b 44 24 04 8b 40 50 8b 40 60 <ff> 88 a4 00 00 00 c3 8b
44 24 04 8b 40 50 8b 40 60 ff 80 a4 00