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Bug 1712977 - test_gdb: test_gc() fails on s390x with: Unable to locate python frame
Summary: test_gdb: test_gc() fails on s390x with: Unable to locate python frame
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: python3
Version: 8.1
Hardware: s390x
OS: Unspecified
low
unspecified
Target Milestone: rc
: 8.0
Assignee: Victor Stinner
QA Contact: Lukáš Zachar
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2019-05-22 15:31 UTC by Charalampos Stratakis
Modified: 2020-04-28 16:08 UTC (History)
11 users (show)

Fixed In Version: python3-3.6.8-16.el8
Doc Type: No Doc Update
Doc Text:
Clone Of: 1678277
Environment:
Last Closed: 2020-04-28 16:07:22 UTC
Type: Bug
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Python 37631 0 None None None 2019-09-24 09:34:14 UTC
Red Hat Product Errata RHSA-2020:1764 0 None None None 2020-04-28 16:08:22 UTC

Description Charalampos Stratakis 2019-05-22 15:31:25 UTC 
+++ This bug was initially created as a clone of Bug #1678277 +++

The s390x job of the Fedora CI fails on building python3 package.

test_gdb.test_gc() failed twice on Python compiled in **debug mode** on s390x arch:

FAIL: test_gc (test.test_gdb.PyBtTests)
Verify that "py-bt" indicates if a thread is garbage-collecting
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/builddir/build/BUILD/Python-3.7.2/Lib/test/test_gdb.py", line 852, in test_gc
    self.assertIn('Garbage-collecting', gdb_output)
AssertionError: 'Garbage-collecting' not found in 'Breakpoint 1 (builtin_id) pending.\n[Thread debugging using libthread_db enabled]\nUsing host libthread_db library "/lib64/libthread_db.so.1".\n\nBreakpoint 1, builtin_id (self=, self@entry=<error reading variable: value has been optimized out>, v=42, v@entry=<error reading variable: value has been optimized out>) at /builddir/build/BUILD/Python-3.7.2/Python/bltinmodule.c:1216\n1216\t    return PyLong_FromVoidPtr(v);\nBreakpoint 2: file /builddir/build/BUILD/Python-3.7.2/Modules/gcmodule.c, line 860.\n[Inferior 1 (process 12917) exited normally]\nUnable to locate python frame\n'

Reformatted gdb catched output:

Breakpoint 1 (builtin_id) pending.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

Breakpoint 1, builtin_id (self=, self@entry=<error reading variable: value has been optimized out>, v=42, v@entry=<error reading variable: value has been optimized out>) at /builddir/build/BUILD/Python-3.7.2/Python/bltinmodule.c:1216
1216	    return PyLong_FromVoidPtr(v);
Breakpoint 2: file /builddir/build/BUILD/Python-3.7.2/Modules/gcmodule.c, line 860.
[Inferior 1 (process 12917) exited normally]
Unable to locate python frame

--- Additional comment from Victor Stinner on 2019-02-18 13:20:32 CET ---

Related bug reports:

* 2015: https://bugzilla.redhat.com/show_bug.cgi?id=1181034#c0 "test_gdb fails on s390(x)" closed as "EOL" (no fixed)
* 2016: https://bugzilla.redhat.com/show_bug.cgi?id=1333064#c0 "/CoreOS/python/Sanity/gdb test is failing on s390x" closed as ERRATA except that no change has been written :-)
* 2016: https://github.com/python/cpython/commit/0d88c652318c4c5eed77fd2e78e9e955ffa5c8d1 fix test_gdb on s390x (ignore some warnings)
* 2018: https://bugs.python.org/issue34007 "test_gdb fails in s390x SLES buildbots" fixed upstream in Python 3.7.1

--- Additional comment from Charalampos Stratakis on 2019-05-22 16:45:46 CEST ---

This seems to be the change that triggered the bug for some reason: https://src.fedoraproject.org/rpms/python3/c/8927d3f2671041d33c2682b47d238c7070474d0e?branch=master
Comment 1 Marcel Plch 2019-06-24 10:38:58 UTC 
I have managed to reproduce the issue.
It seems like the compiler on s390x arch inlines functions even with -O0 (and therefore with -Og too) in CFLAGS, when certain flags are specified.

I'm trying to isolate the minimum set of flags required to reproduce the issue.
Comment 2 Marcel Plch 2019-07-19 11:51:48 UTC 
The problem emerges from bad compiler flags handling.
I have submitted an upstream issue:
https://bugs.python.org/issue37631?
Comment 3 Charalampos Stratakis 2019-10-03 00:17:12 UTC 
This issue can be fixed by making the following change to the SPEC:

-  make EXTRA_CFLAGS="$CFLAGS $MoreCFlags" %{?_smp_mflags}
+  %make_build CFLAGS_NODIST="$CFLAGS_NODIST $MoreCFlags"

This will make the -Og the be appended to the end of the compiler flags, since CFLAGS_NODIST are appended at the end as well. As it stands now, CFLAGS_NODIST contains the -O2 which overrides -Og for the debug build.

The same fix also resolves bug 1714733
Comment 4 Charalampos Stratakis 2019-10-03 01:10:14 UTC 
As a side note, when trying to change -Og to -O0 the debug build, the compilation segfaults, as the hardening flags that are enabled by default, require optimizations higher than -O0
Comment 8 errata-xmlrpc 2020-04-28 16:07:22 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2020:1764
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