[ltt-dev] LTTng 2.0 on ARM

[Avik Sil]

On Wednesday 21 September 2011 07:41 PM, Mathieu Desnoyers wrote:
> * Mathieu Desnoyers (compudj at krystal.dyndns.org) wrote:
>> * Avik Sil (avik.sil at linaro.org) wrote:
>>> Hi Mathieu,
>>>
>>> Now as the ARM patch is in, I'm able to generate trace and read the
>>> trace with babeltrace on Pandaboard. But while enabling the events, I
>>> get following output:
>>>
>>> # lttng enable-event -a -k
>>> [ 4304.827819] BUG: spinlock bad magic on CPU#1, ltt-sessiond/1305
>>> [ 4304.841735]  lock: 81453c00, .magic: 00000000, .owner: <none>/-1,
>>> .owner_cpu: 0
>>> [ 4304.857421] [<800110ad>] (unwind_backtrace+0x1/0x90) from
>>> [<8022c847>] (do_raw_spin_lock+0x17/0xfc)
>>> [ 4304.875213] [<8022c847>] (do_raw_spin_lock+0x17/0xfc) from
>>> [<7f97c30f>] (channel_create+0xd6/0x158 [lib_ring_buffer])
>>> [ 4304.894866] [<7f97c30f>] (channel_create+0xd6/0x158
>>> [lib_ring_buffer]) from [<7f99856b>] (_channel_create+0x28/0x32
>>> [ltt_ring_buffer_client_discard])
>>> [ 4304.917755] [<7f99856b>] (_channel_create+0x28/0x32
>>> [ltt_ring_buffer_client_discard]) from [<7f98b507>]
>>> (ltt_channel_create+0x12a/0x190 [ltt_relay])
>>> [ 4304.940551] [<7f98b507>] (ltt_channel_create+0x12a/0x190 [ltt_relay])
>>> from [<7f98c34b>] (lttng_abi_create_channel+0xba/0x158 [ltt_relay])
>>> [ 4304.962341] [<7f98c34b>] (lttng_abi_create_channel+0xba/0x158
>>> [ltt_relay]) from [<7f98c43f>] (lttng_session_ioctl+0x56/0x64 [ltt_relay])
>>> [ 4304.984436] [<7f98c43f>] (lttng_session_ioctl+0x56/0x64 [ltt_relay])
>>> from [<800baa49>] (do_vfs_ioctl+0x1a5/0x1dc)
>>> [ 4305.004394] [<800baa49>] (do_vfs_ioctl+0x1a5/0x1dc) from [<800baab3>]
>>> (sys_ioctl+0x33/0x4c)
>>> [ 4305.022369] [<800baab3>] (sys_ioctl+0x33/0x4c) from [<8000c2c1>]
>>> (ret_fast_syscall+0x1/0x50)
>>> All kernel events are enabled in channel channel0
>>>
>>> Can you please look into this issue?
>>
>> Yes, it looks like I missed a spinlock initialization in there. Can you
>> try with the following commit applied ?
>>
>> commit 6fb8de4b6c1e8dcc69ff6f67310c5cf29718101a
>> Author: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
>> Date:   Wed Sep 21 10:08:34 2011 -0400
>>
>>     lib ring buffer frontend: add missing lock initialization
> 
> Silly me. Also make sure you have commit
> 02a766bbaa8b112e87d88aa4a70a507f5a6deb99, which marks the new init
> function as a module_init().
>
Thanks! With this patch the spinlock error disappears.

Regards,
Avik

> Thanks,
> 
> Mathieu