BUG: unable to handle kernel paging request on 2.6.33-rc2

Hi:

When I perform "echo mem > /sys/power/state", I got BUG on
rs600_gart_set_page, then suspend hangs.

    I don't have a camera to log the outputs, the call trace are:

    rs600_gart_set_page+0x31
    radeon_gart_bind
    radeon_ttm_backend
    ttm_tt_bind
    ttm_bo_handle_move_mem
    ttm_mem_evict_fist
    ttm_bo_force_list_clean
    ttm_bo_evict_vram
    ttm_suspend_kms
    radeon_pci_suspend
    pci_legacy_suspend
    pci_pm_suspend
    pm_op
    dpm_suspend
    suspend_devices_and_enter
    enter_state
    state_store
    kobj_attr_store
    sysfs_write_file
    vfs_write
    sys_write
    system_call_fastpath

    l *rs600_gart_set_page+0x31 is in writeq, maybe this is a possible 

use-after-free. Thanks.