Weird strace of #! python script

Dan Stromberg drsalists at
Mon Mar 14 21:37:06 UTC 2022

I posted to python-list about the matter here:

...but it may be more relevant to strace-devel.

Thanks for reading!

Here's the text of the python-list post:

Hi folks.

First off, I know, python2 is ancient history.  Porting to 3.x is on my
list of things to do (though I'm afraid it's not yet at the top of the
list), and the same thing happens with python3.

So anyway, I'm strace'ing a #!/usr/bin/python2 script.

I expected to see an exec of /usr/bin/python2, but I don't.  I just see an
exec of /tmp/t.

As follows:
tact at celery_worker:/app$ strace -f -s 1024 -o /tmp/t.strace /tmp/t
[1]+  Stopped                 strace -f -s 1024 -o /tmp/t.strace /tmp/t
tact at celery_worker:/app$ bg
[1]+ strace -f -s 1024 -o /tmp/t.strace /tmp/t &
tact at celery_worker:/app$ ps axf
 1163 pts/0    Ss     0:00 bash
 1363 pts/0    S      0:00  \_ strace -f -s 1024 -o /tmp/t.strace /tmp/t
 1366 pts/0    S      0:00  |   \_ /usr/bin/python2 /tmp/t
 1367 pts/0    R+     0:00  \_ ps axf
tact at celery_worker:/app$ fg
bash: fg: job has terminated
[1]+  Done                    strace -f -s 1024 -o /tmp/t.strace /tmp/t
tact at celery_worker:/app$ grep execve /tmp/t.strace
1366  execve("/tmp/t", ["/tmp/t"], 0x7ffd89f9c3b8 /* 49 vars */) = 0
tact at celery_worker:/app$

I've deleted some irrelevant processes from the 'ps axf'.

/tmp/t is actually just:
tact at celery_worker:/app$ cat /tmp/t

import time


Was this some sort of security feature I never heard about?  I'm tracing a
very simple time.sleep(10) here, but the same thing is (not) happening in a
larger script that I need to track down a bug in.

Is there a way I can coax Linux and/or strace to show all the exec's, like
they used to?  Not having them makes me wonder what else is missing from
the strace report.

I'm on a Debian 11.2 system with strace 5.10 and Python 2.7.18.

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