Re: Crash

it looks like that dsp_Function get called from two different threads.
dsp_core.c - function dsp_function:
1. hh->prim == PH_DEACTIVATE_REQ - ch->recv(ch->peer, skb) - crash occurs
2. hh->prim == PH_DEACTIVATE_CNF - dsp->up->send(dsp->up, skb) returns 0

dsp_function switch enter PH_DEACTIVATE_REQ
dsp_function before ch->recv(ch->peer, skb)
dsp_function: enter
dsp_function switch enter PH_DEACTIVATE_CNF
before dsp->up->send(dsp->up, skb)
valuex: 0
dsp_function after ch->recv(ch->peer, skb) returns: 0
CPU 0 Unable to handle kernel paging request at virtual address c1081088,
epc == c1163fcc, ra == c1163af0
Oops[#1]:

Do you have any idee how to debug any further ?

regard,

2013/5/9 kkjoe kkjoe <[email protected]>

> Yes i have recompiled both, kernel and module with debugging symbols.
> I've add some more printks in dsp_function and got these:
>
> Printk before crash:
>
> dsp_function before skb_queue_purge(&dsp->sendq);
> dsp_function before spin_unlock_irqrestore
> dsp_function before ch->recv(ch->peer, skb)
> dsp_function enter
> dsp_function switch enter PH_DEACTIVATE_CNF
> dsp_function: b_channel is now inactive DSP_C2(0xc10b8000)
> dsp_function exit before dsp->up->send(dsp->up, skb)
> CPU 0 Unable to handle kernel paging request at virtual address c10b8088,
> epc == c10821e8, ra == c10821dc
> Oops[#1]:
>
> Sourcecode:
>
> case (PH_DEACTIVATE_CNF):
>             printk(KERN_DEBUG "dsp_function switch enter
> PH_DEACTIVATE_CNF\n");
>             printk(KERN_DEBUG "%s: b_channel is now inactive %s\n",
>                    __func__, dsp->name);
>         /* bchannel now inactive */
>         spin_lock_irqsave(&dsp_lock, flags);
>         dsp->b_active = 0;
>         dsp->data_pending = 0;
>         dsp_cmx_hardware(dsp->conf, dsp);
>         dsp_rx_off(dsp);
>         spin_unlock_irqrestore(&dsp_lock, flags);
>         hh->prim = DL_RELEASE_CNF;
>         if (dsp->up) {
>             printk(KERN_DEBUG "dsp_function exit before
> dsp->up->send(dsp->up, skb)\n");
>             return dsp->up->send(dsp->up, skb);
>         }
>         break;
>
> It seems that dsp->up->send is last function before crash occurs.
>
> regards,
>
>
> 2013/5/9 Andreas Eversberg <[email protected]>
>
>>  kkjoe kkjoe wrote:
>>
>>  Hello,
>>
>> i have recompiled the kernel and the module and could reproduce the oops.
>>
>> [<c1166438>] dsp_function+0x994/0x1e3c [mISDN_dsp]
>> [<c0059a88>] bchannel_bh+0x130/0x148 [mISDN_core]
>> [<8013dd38>] run_workqueue+0xb4/0x2d0
>> [<8013ed64>] worker_thread+0x94/0x140
>> [<80143a3c>] kthread+0x80/0xa8
>> [<80106010>] kernel_thread_helper+0x10/0x18
>>
>> // Get Symbol offset
>> /mnt/cf0/modules/misdn # cat /sys/module/mISDN_dsp/sections/.init.text
>> 0xc0079000
>>
>> // Load Symbol file
>> /mnt/cf0/modules/misdn # /mnt/cf0/bin/gdb mISDN_dsp.ko
>> GNU gdb 6.8
>> Copyright (C) 2008 Free Software Foundation, Inc.
>> License GPLv3+: GNU GPL version 3 or later <
>> http://gnu.org/licenses/gpl.html>
>> This is free software: you are free to change and redistribute it.
>> There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
>> and "show warranty" for details.
>> This GDB was configured as "mipsel-unknown-linux-gnu"...
>> (gdb) add-symbol-file /mnt/cf0/modules/misdn/mISDN_dsp.o 0xc0079000
>> add symbol table from file "/mnt/cf0/modules/misdn/mISDN_dsp.o" at
>>     .text_addr = 0xc0079000
>> (y or n) y
>> Reading symbols from /mnt/cf0/modules/misdn/mISDN_dsp.o...done.
>> (gdb)
>>
>> // Get source line  - does not work
>> (gdb) b *dsp_function + 0x994
>> Breakpoint 1 at 0x1438
>>  -> I do not get any source line
>> // get start location
>> (gdb) disassemble dsp_function
>> Dump of assembler code for function dsp_function:
>> 0x00000aa4 <dsp_function+0>:    addiu    sp,sp,-88
>>
>> (gdb) b *dsp_function + 0x00001e3c
>> Breakpoint 3 at 0x28e0: file
>> /home/kkjoe/test/test1/mIsdn/mISDN/standalone/drivers/isdn/mISDN/dsp_cmx.c,
>> line 1922.
>>
>>  best regards and thank you very much for your support
>>
>>
>> 2013/5/9 jolly <[email protected]>
>>
>>> kkjoe kkjoe wrote:
>>> > Do i have to rebuild the kernel and the misdn modules with debugging
>>> > information ?
>>>  yes.
>>>
>>
>>  can you try to test some words before and after, like 0x988-0x99f ?
>> area there lines close before and after the crash point? did you re-compile
>> misdn after adding kernel debugging? anyone else an idea how to find that
>> line?
>>
>>
>

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