How to get the detailed kernel stack trace if specified fuction takes too long to finish?

[Josh Stone]

On 04/02/2014 03:25 AM, liang xie wrote:
> I tried the last scheduler script, the output just like this:
> # stap --all-modules y.stp
> WARNING: missing unwind/symbol data for module 'uprobes'
> long sys_write in tid 10162
> Systemtap probe: kernel.trace("sched_switch")
> long sys_write in tid 11510
> Systemtap probe: kernel.trace("sched_switch")
> long sys_write in tid 11288
> Systemtap probe: kernel.trace("sched_switch")
> 
> I could not figure out why "print_backtrace()" didn't output any log:)

Ah, this "Systemtap probe:" message is fairly old.

>>> My OS:2.6.32-220.el6.x86_64
>>> # stap -V
>>> Systemtap translator/driver (version 1.6/0.152 non-git sources)

Is it possible for you to update your systemtap rpm?  1.6 was released
with RHEL 6.2 (presumably CentOS 6.2 as well), and we've since released
systemtap-1.7 in 6.3, 1.8 in 6.4, and 2.3 in 6.5.  I believe at least
systemtap-1.8 will work better for you here.

Josh