Messages in this thread | | | Date | Mon, 8 Apr 2013 07:01:12 -0400 | From | Theodore Ts'o <> | Subject | Re: Excessive stall times on ext4 in 3.9-rc2 |
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On Sun, Apr 07, 2013 at 05:59:06PM -0400, Frank Ch. Eigler wrote: > > 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?
Is there any reason why the error message couldn't be simplified, to something as "kernel symbol not found"? I wasn't sure if the problem was that there was some incompatibility between a recent change with kprobe and systemtap, or parse failure in the systemtap script, etc.
> Systemtap could endavour to list roughly-matching functions that do > exist, if you think that's be helpful.
If the goal is ease of use, I suspect the more important thing that systemtap could do is to make its error messages more easily understandable, instead of pointing the user to read a man page where the user then has to figure out which one of a number of failure scenarios were caused by a particularly opaque error message. (The man page doesn't even say that "semantic error while resolving probe point" means that a kernel function doesn't exist -- especially complaining about the kprobe identifier points the user in the wrong direction.)
- Ted
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