Re: SystemTap 3.0 doesn't work on Ubuntu 14.04.4 LTS

[Aleksander Alekseev <mail at eax dot me>]

Hello

Thanks for your replies!

> What issues do you have?
> It is certainly supposed to build against elfutils 0.165.

`make` fails like this:

http://pastebin.com/raw/afHGbFpE

> As noted in that answer, can you provide "objdump -d" around those
> addresses?

Could you please explain how to find reported address (e.g.
0xffffffff81205870) in objdump output? Here is a full output of `sudo
objdump -dr /boot/vmlinuz-4.2.0-27-generic` command:

https://www.dropbox.com/s/w9iywua0c6pdkju/vmlinux.decoded.gz?dl=0

I hope at list this is a right assembly code? :)

Also here is an output of `stap -vv`:

http://pastebin.com/raw/GEdMqL7U

> Are you sure the dbgsym you downloaded is an exact match for your
> kernel?  It should have failed earlier if it wasn't, but a mismatch
> could lead us to attempt kprobes on weird addresses, like in the
> middle of an instruction.

`uname -r` says `4.2.0-27-generic` and installed packages are:

linux-headers-4.2.0-27
linux-headers-4.2.0-27-generic
linux-image-4.2.0-27-generic
linux-image-4.2.0-27-generic-dbgsym
linux-image-extra-4.2.0-27-generic

Looks right. Is it any other way to check this?

> Another thing to try is instead use "nd_syscall.open" etc. which will
> probe functions by name, without requiring debuginfo at all.

Wow, it works! So... why I need debuginfo in the first place? Are there
any features that will not work without it or something like this?

-- 
Best regards,
Aleksander Alekseev
http://eax.me/