Re: crash on CONFIG_CFAG12864B=y in 2.6.20-rc3-mm1

From: Miguel Ojeda
Date: Thu Feb 01 2007 - 08:52:49 EST


On 1/7/07, Daniel Walker <dwalker@xxxxxxxxxx> wrote:
(forgot to CC LKML)

The options,

CONFIG_CFAG12864B=y
CONFIG_CFAG12864B_RATE=20

causes a crash at boot in 2.6.20-rc3-mm1. I don't have the hardware
associated with the options. It looks like it just doesn't have guards
to detect if the hardware doesn't exists.

Here is the crash,

ks0108: ERROR: parport didn't find 888 port
BUG: unable to handle kernel NULL pointer dereference at virtual address
0000004 printing eip:
c02dbff9
*pde = 00000000
Oops: 0000 [#1]
PREEMPT SMP
last sysfs file:
Modules linked in:
CPU: 3
EIP: 0060:[<c02dbff9>] Not tainted VLI
EFLAGS: 00010246 (2.6.20-rc3-mm1 #11)
EIP is at ks0108_writecontrol+0x79/0xc0
eax: 00001008 ebx: 0000000a ecx: 673e2eb8 edx: 00000001
esi: 0000000a edi: 00000000 ebp: f7c3ff6c esp: f7c3ff50
ds: 007b es: 007b fs: 00d8 gs: 0000 ss: 0068
Process swapper (pid: 1, ti=f7c3e000 task=f7c26a90 task.ti=f7c3e000)
Stack: 00000001 f7552c40 f7c3ff60 c0120e3f 00000000 c049f450 00000000
f7c3ff74
c02dc159 f7c3ff80 c02dc177 00000000 f7c3ff98 c048feda 00000378
c02d74db
00000000 00000000 f7c3ffe0 c0478610 c03d9d35 00000004 f7c26a90
c0473fc4
Call Trace:
[<c01053da>] show_trace_log_lvl+0x1a/0x30
[<c0105499>] show_stack_log_lvl+0xa9/0xd0
[<c01056c7>] show_registers+0x207/0x370
[<c0105949>] die+0x119/0x250
[<c011d267>] do_page_fault+0x277/0x610
[<c038e9d4>] error_code+0x7c/0x84
[<c02dc159>] cfag12864b_e+0x19/0x20
[<c02dc177>] cfag12864b_page+0x17/0x30
[<c048feda>] cfag12864b_init+0x8a/0x130
[<c0478610>] init+0x110/0x250
[<c0104fd3>] kernel_thread_helper+0x7/0x14
=======================
Code: 8b 98 ec 00 00 00 0f b6 03 24 df 88 45 f3 80 75 f3 20 0f b6 43 01 20
45 f
EIP: [<c02dbff9>] ks0108_writecontrol+0x79/0xc0 SS:ESP 0068:f7c3ff50
<0>Kernel panic - not syncing: Attempted to kill init!





As Daniel Walker pointed out, the driver doesn't probe for the
hardware because it just uses the parallel port for output (there
isn't any kind of input).

The driver shouldn't continue execution and using
ks0108_writecontrol() (which writes to the parallel port) after the
"ks0108: ERROR: parport didn't find 888 port" message.

Will check.

Thanks for the warning,
Miguel

(forgot to reply to all).

--
Miguel Ojeda
http://maxextreme.googlepages.com/index.htm
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