Messages in this thread | | | Subject | Re: Excessive stall times on ext4 in 3.9-rc2 | From | (Frank Ch. Eigler) | Date | Sun, 07 Apr 2013 17:59:06 -0400 |
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Hi -
tytso wrote:
> So I tried to reproduce the problem, and so I installed systemtap > (bleeding edge, since otherwise it won't work with development > kernel), and then rebuilt a kernel with all of the necessary CONFIG > options enabled: > > CONFIG_DEBUG_INFO, CONFIG_KPROBES, CONFIG_RELAY, CONFIG_DEBUG_FS, > CONFIG_MODULES, CONFIG_MODULE_UNLOAD > [...]
That sounds about right.
> I then pulled down mmtests, and tried running watch-dstate.pl, which > is what I assume you were using [...]
I just took a look at the mmtests, particularly the stap-fix.sh stuff. The heroics therein are really not called for. git kernel developers should use git systemtap, as has always been the case. All compatibility hacks in stap-fix.sh have already been merged, in many cases for months.
> [...] > semantic error: while resolving probe point: identifier 'kprobe' at /tmp/stapdjN4_l:18:7 > source: probe kprobe.function("get_request_wait") > ^ > Pass 2: analysis failed. [man error::pass2] > Unexpected exit of STAP script at ./watch-dstate.pl line 296. > I have no clue what to do next. Can you give me a hint?
You should see the error::pass2 man page, which refers to error::reporting, which refers to involving stap folks and running stap-report to gather needed info.
But in this case, that's unnecessary: the problem is most likely that the get_request_wait function does not actually exist any longer, since
commit a06e05e6afab70b4b23c0a7975aaeae24b195cd6 Author: Tejun Heo <tj@kernel.org> Date: Mon Jun 4 20:40:55 2012 -0700
block: refactor get_request[_wait]()
Systemtap could endavour to list roughly-matching functions that do exist, if you think that's be helpful.
- FChE
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