00:00 <Vall> OK, systemtap-doc man pages installed, "man error::pass5" now works, having a look

00:00 <fche> righto

00:13 <Vall> man page was not very helpful... nothing specific about the error abovr

00:13 <Vall> *above

00:14 <Vall> anyway, just tried using filename directly in the printf, as you suggested

00:14 <Vall> it aborts right off:

00:14 <Vall> stap -e 'probe syscall.execve { printf("%d %d %s exec %s\n", pid(), ppid(), execname(), filename) }'

00:14 <Vall> ERROR: user string copy fault -14 at 0000000000439486 near identifier 'user_string_n' at /usr/share/systemtap/tapset/uconversions.stp:120:10

00:15 <Vall> trying with argstr now

00:17 <Vall> exactly the same thing happens with argstr as with the kernel_string($filename): it runs for a while, and then aborts with ERROR: user string copy fault -14 at 0000000000439486 near identifier 'user_string_n' at /usr/share/systemtap/tapset/uconversions.stp:120:10

00:17 <Vall> :-(

00:17 <Vall> Any ideas, fche?

01:19 <fche> Vall, hi, the man page (current version) says to try --suppress-handler-errors or --skip-badvars stap options

01:19 <fche> these things can happen e.g. if the syscall parameters reside in user memory that hasn't actually been paged in yet

12:45 <Vall> back

12:45 <Vall> fell asleep last night ;-)

12:45 <Vall> fche: thanks for the suggestion, will try.

13:01 <Vall> fche: seems like it solved the issue, my one-liner above has been running for almost half an hour and hasn't aborted yet

13:02 <Vall> will let it run a little more until I declare that fixed

13:38 <fche> righto

13:40 <fche> I believe newer systemtap has that more automated, in the sense that user-space strings that are unavailable will get the hex address substituted instead of an outright error

21:39 <Vall> fche, just reporting back that I've left my one-liner running the whole day and it is working OK; I think we can now safely say that your suggestion of adding the " --suppress-handler-errors" and "--skip-badvars" options (I'm running with both) have indeed fixed the issue. Many thanks for your help!

21:54 <fche> righto

21:55 <fche> also see if a newer version of stap can be made available for your distro; it takes care of this particular complication automatically