14:52 <Minnozz> hi, I built systemtap 3.0 on Ubuntu 14.04 (because the version in the repository doesn't work with kernel >= 3.15) and I am getting "ERROR: user string copy fault -14 at 00007ff3c4b2e658 [man error::fault] near identifier 'user_string_n' at /usr/local/share/systemtap/tapset/uconversions.stp:133:10"

14:53 <Minnozz> does that ring a bell with anyone?

14:53 <fche> Minnozz, that can be expected (tm) if e.g. that part of the userspace program's memory hasn't been paged in

14:53 <fche> so it depends on script & context

14:53 <Minnozz> ah

14:53 <fche> can use try { } catch { } or stap --skip-badvars to work around such things

14:55 <Minnozz> fche: thanks. is this still expected if I only use user_string($argN) in my script?

14:56 <fche> yes, [man function::user_string] mentions the possibility of errors

14:56 <fche> and see also [man error::fault]

14:57 <Minnozz> thank you, I'll look into that

15:08 <Minnozz> ah right, I'm passing in a pointer, but what it points to isn't necessarily paged in

15:08 <Minnozz> re: my question about $argN

15:08 <fche> yup

15:08 <fche> so esp. at the early startup of a program, this can happen

15:10 <Minnozz> I suspect it's a string literal I'm passing in

15:13 <fche> could be. one way to check would be to put a strlen(foo) into your c program, to force it to be paged in. or an mlockall() syscall.

15:13 <fche> or

15:13 <fche> use user_string_quoted()