spidev dma test

gistfile1.txt

root@debian:~# echo 1 > /dev/spidev32766.0 
spi_master spi32766: tfr->tx_buf =   (null), t->len = 2 
spi_master spi32766: tfr->rx_buf = ee82d000, t->len = 2 
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = c0003000
[00000000] *pgd=80000040004003, *pmd=00000000
Internal error: Oops: 2a07 [#1] PREEMPT SMP THUMB2
CPU: 0 PID: 48 Comm: spi32766 Not tainted 3.17.0-rc3-00064-ga5e9ad57-dirty #7
task: ee8cf200 ti: eeb64000 task.ti: eeb64000
PC is at v7_dma_inv_range+0x2c/0x40
LR is at dma_cache_maint_page+0x6d/0xf0
pc : [<c0017026>]    lr : [<c0013e75>]    psr: 00001833
sp : eeb65e28  ip : 00000000  fp : c048045c
r10: 00080000  r9 : ef7f8000  r8 : c04b56c0
r7 : 00000002  r6 : 00000000  r5 : 00000002  r4 : 00000000
r3 : 0000003f  r2 : 00000040  r1 : 00000000  r0 : 00000000
Flags: nzcv  IRQs on  FIQs on  Mode SVC_32  ISA Thumb  Segment kernel
Control: 70c5387d  Table: 6d4a9740  DAC: fffffffd
Process spi32766 (pid: 48, stack limit = 0xeeb64240)
Stack: (0xeeb65e28 to 0xeeb66000)
5e20:                   00000002 eeb62a00 c0017095 00000000 ef7f8000 eeb65ec0
5e40: 00000000 00000001 eeb65ec0 c0013f3b c0017095 c01658f5 c0009149 00000000
5e60: c0013ef9 c04850a8 eeb62a00 c001413b 00000002 00000000 00000000 00000002
5e80: ee2b9f04 eeb62bc0 00000000 c00140e5 00000003 c04efa00 00001f40 ee2b9ed4
5ea0: ee2b9f04 c018fb3d 00000000 c03126a5 ef5c85a2 00000000 00000002 6e82d000
5ec0: ef7f8002 00000000 00000002 00000000 eeb62a00 00000001 00000000 c0497a80
5ee0: eeb62b7c c018dab7 00000001 00000000 eeb65ef8 eeb62a00 ee2b9ed4 eeb62b64
5f00: 00000001 eeb62b40 00000000 00000000 00000000 c018d9b5 00000001 c0036b71
5f20: 00000001 eeb62b54 eeb62b3c eeb64000 00000001 eeb62b40 00000000 00000000
5f40: 00000000 c00285a7 00000000 eeb4ea80 00000000 eeb62b3c c0028541 00000000
5f60: 00000000 c0028105 baff7ff7 00000000 dfd97b7f eeb62b3c 00000000 00000000
5f80: eeb65f80 eeb65f80 00000000 00000000 eeb65f90 eeb65f90 00000000 eeb4ea80
5fa0: c002807d 00000000 00000000 c000cddd 00000000 00000000 00000000 00000000
5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
5fe0: 00000000 00000000 00000000 00000000 00000013 00000000 f7f2ef5f 5b93fffb
[<c0017026>] (v7_dma_inv_range) from [<c0013e75>] (dma_cache_maint_page+0x6d/0xf0)
[<c0013e75>] (dma_cache_maint_page) from [<c0013f3b>] (arm_dma_map_page+0x43/0x50)
[<c0013f3b>] (arm_dma_map_page) from [<c001413b>] (arm_dma_map_sg+0x57/0xa0)
[<c001413b>] (arm_dma_map_sg) from [<c018fb3d>] (sun6i_spi_transfer_one+0x1dd/0x31c)
[<c018fb3d>] (sun6i_spi_transfer_one) from [<c018dab7>] (spi_transfer_one_message+0x47/0x13c)
[<c018dab7>] (spi_transfer_one_message) from [<c018d9b5>] (spi_pump_messages+0x20d/0x2c8)
[<c018d9b5>] (spi_pump_messages) from [<c00285a7>] (kthread_worker_fn+0x67/0xa0)
[<c00285a7>] (kthread_worker_fn) from [<c0028105>] (kthread+0x89/0xa0)
[<c0028105>] (kthread) from [<c000cddd>] (ret_from_fork+0x11/0x34)