[ltt-dev] lttng enabled SMP kernel soft locks up

[vchitlur@cisco.com (Venkatesh Babu Chitlur Srinivasa (vchitlur))]

-----Original Message-----
From: Mathieu Desnoyers [mailto:compudj@krystal.dyndns.org]

> Can you provide your .config for both the kernel that works and the
> kernel that doesn't ?

  Please see the attached config files.

> Maybe some other kernel option got selected. Also,
> please try to disable the added LTTng options (diffing between the two
> config files will help you there) to see if it helps.

The difference between the working config (.config.2.6.35.4) and non-working config (.config.2.6.35.4.lttng) is shown below:

[root at arch-lab4 linux-2.6.35]# diff .config.2.6.35.4.lttng .config.2.6.35.4
4c4
< # Thu Sep 23 09:55:03 2010
---
> # Thu Sep 23 08:35:21 2010
129,133d128
< CONFIG_HAVE_GET_CYCLES=y
< CONFIG_HAVE_TRACE_CLOCK=y
< # CONFIG_HAVE_TRACE_CLOCK_GENERIC is not set
< # CONFIG_HAVE_TRACE_CLOCK_32_TO_64 is not set
< CONFIG_HAVE_UNSYNCHRONIZED_TSC=y
188d182
< CONFIG_MARKERS=y
215,217d208
< CONFIG_HAVE_IMMEDIATE=y
< CONFIG_IMMEDIATE=y
< CONFIG_HAVE_LTT_DUMP_TABLES=y

So I disabled all LTTNG config variables as follows and rebuilt the kernel. But even this one is having the same soft lockup problem.

[root at arch-lab4 linux-2.6.35]# diff .config .config.2.6.35.4
4c4
< # Thu Sep 23 09:55:03 2010
---
> # Thu Sep 23 08:35:21 2010
129,133d128
< # CONFIG_HAVE_GET_CYCLES is not set
< # CONFIG_HAVE_TRACE_CLOCK is not set
< # CONFIG_HAVE_TRACE_CLOCK_GENERIC is not set
< # CONFIG_HAVE_TRACE_CLOCK_32_TO_64 is not set
< # CONFIG_HAVE_UNSYNCHRONIZED_TSC is not set
188d182
< # CONFIG_MARKERS is not set
215,217d208
< # CONFIG_HAVE_IMMEDIATE is not set
< # CONFIG_IMMEDIATE is not set
< # CONFIG_HAVE_LTT_DUMP_TABLES is not set


> Another point is to make sure you reinstall your modules too (make
> modules_install) when you deploy the lttng-patched kernel, and make sure
> you re-create your initrd if you have one.


 I did reinstall the modules and also re-created the initrd. Still the same problem.

 The only way I was able to get LTTng patched kernel booted up without soft lockup is with UP kernel (I disabled the SMP in config menu).

Regards,
  VBabu


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