Subject: Re: bug#56962: [PATCH] gnu: Add perf-tools.

From: Olivier Dion <[email-masked]>
Date: Fri, 05 Aug 2022 10:18:34 -0400

On Fri, 05 Aug 2022, Mathieu Othacehe <[email-masked]> wrote:
>> * gnu/packages/instrumentation.scm (perf-tools): New variable.
>
> Nice one. It looks like execsnoop is not working here, any idea why?
>
> --8<---------------cut here---------------start------------->8---
> mathieu@meije ~/guix [env]$ sudo execsnoop 
> Tracing exec()s. Ctrl-C to end.
> ERROR: adding a kprobe for execve. Exiting.
> --8<---------------cut here---------------end--------------->8---
>

Hmm I don't know.  `sudo cat /sys/kernel/debug/kprobes/enabled' gives
`1' so kprobe should work correctly.  Also:
--8<---------------cut here---------------start------------->8---
$ zcat /proc/config.gz | grep KPROBES
CONFIG_KPROBES=y
CONFIG_KPROBES_ON_FTRACE=y
CONFIG_HAVE_KPROBES=y
CONFIG_HAVE_KPROBES_ON_FTRACE=y
--8<---------------cut here---------------end--------------->8---

killsnoop also fails.  It seems that the problem is here:
--8<---------------cut here---------------start------------->8---
 133 ### select awk
 134 # workaround for mawk fflush()
 135 [[ -x /usr/bin/mawk ]] && awk="mawk" && mawk -W interactive && \
 136 [ $? -eq 0 ] && awk="mawk -W interactive"
 137 # workaround for gawk strtonum()
 138 [[ -x /usr/bin/gawk ]] && awk="gawk --non-decimal-data"
--8<---------------cut here---------------end--------------->8---

Substituing /usr/bin/gawk seems to fix it.  I'll open a new bug thread.

-- 
Olivier Dion
oldiob.dev