New bug?

[Alexander Shiyan <shc_work@xxxxxxx>]

Hello.

During testing functions transfer_one(), stumbled upon an error.
I'm using kernel 3.13, so I had to apply a patch from upstream
(spi: core: Fix transfer failure when master->transfer_one returns positive value).
After applying all becomes normal with probing, but where did the error
"Unable to handle kernel NULL pointer dereference" ?
Did someone have similar bugs?

Thanks.

spi_master spi0: failed to transfer one message from queue: 1
74x164 spi0.1: Failed writing: 1
74x164: probe of spi0.1 failed with error 1
Unable to handle kernel NULL pointer dereference at virtual address 00000020
CAN device driver interface
pgd = c0024000
[00000020] *pgd=00000000
Internal error: Oops: 63c11805 [#1] PREEMPT ARM
CPU: 0 PID: 22 Comm: spi0 Not tainted 3.13.3 #1
task: c396b260 ti: c396e000 task.ti: c396e000
PC is at spi_pump_messages+0x150/0x194
LR is at spi_pump_messages+0x148/0x194
pc : [<c02b690c>]    lr : [<c02b6904>]    psr: 60000013
sp : c396ff20  ip : c04806c4  fp : 00000000
r10: 00000000  r9 : 00000000  r8 : c396b19c
r7 : 00000001  r6 : c396b020  r5 : 00000001  r4 : c396b1b0
r3 : 00000000  r2 : 00000000  r1 : 20000093  r0 : c396b020
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
Control: 0000217f  Table: c0024017  DAC: 00000017
Process spi0 (pid: 22, stack limit = 0xc396e1c0)
Stack: (0xc396ff20 to 0xc3970000)
ff20: c396b1b0 c396b18c c396e000 c004a93c 00000000 c396ad60 00000000 c396b18c
ff40: c004a8a0 00000000 00000000 c004a318 ffefb1cc 00000000 ffff3348 c396b18c
ff60: 00000000 00000001 dead4ead ffffffff ffffffff c396ff74 c396ff74 00000000
ff80: 00000001 dead4ead ffffffff ffffffff c396ff90 c396ff90 c396ffac c396ad60
ffa0: c004a264 00000000 00000000 c0029330 00000000 00000000 00000000 00000000
ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
ffe0: 00000000 00000000 00000000 00000000 00000013 00000000 efff23cc fd5f33cc
[<c02b690c>] (spi_pump_messages+0x150/0x194) from [<c004a93c>] (kthread_worker_fn+0x9c/0xf0)
[<c004a93c>] (kthread_worker_fn+0x9c/0xf0) from [<c004a318>] (kthread+0xb4/0xd0)
[<c004a318>] (kthread+0xb4/0xd0) from [<c0029330>] (ret_from_fork+0x14/0x24)
Code: e1a02005 ebfef650 e5943040 e1a00006 (e5835020)
---[ end trace 3e93175567c311da ]---

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