850398 – python backtrace "py-bt" gdb command doesn't work on x86_64

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Bug 850398 - python backtrace "py-bt" gdb command doesn't work on x86_64

Summary: python backtrace "py-bt" gdb command doesn't work on x86_64

Keywords:
Status:	CLOSED CURRENTRELEASE
Alias:	None
Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	python
Sub Component:
Version:	7.0
Hardware:	x86_64
OS:	Unspecified
Priority:	medium
Severity:	low
Target Milestone:	rc
Target Release:	---
Assignee:	Python Maintainers
QA Contact:	Branislav Náter
Docs Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+	depends on / blocked

Reported:	2012-08-21 14:22 UTC by Branislav Náter
Modified:	2014-06-13 12:43 UTC (History)
CC List:	2 users (show)
Fixed In Version:
Doc Type:	Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed:	2014-06-13 12:43:36 UTC
Target Upstream Version:
Embargoed:
Flags:	bnater: needinfo-

Attachments	(Terms of Use)

Description Branislav Náter 2012-08-21 14:22:38 UTC

Description of problem:
Looks like there is regression in printing feature on x86_64 architecture. Feature does work correctly on ppc64 and s390x.

Version-Release number of selected component (if applicable):
python-2.7.3-7.el7.x86_64
python-debuginfo-2.7.3-7.el7.x86_64
gdb-7.4.50.20120120-46.el7.x86_64

How reproducible:
Output from automated test:

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
:: [   LOG    ] :: Test
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff6e84ebf in __strlen_sse42 () from /lib64/libc.so.6
#10 Frame 0x6e3180, for file /usr/lib64/python2.7/ctypes/__init__.py, line 504, in string_at (ptr=3735928559, size=-1)
    return _string_at(ptr, size)
#14 (frame information optimized out)
#17 Frame 0x6d93a0, for file test.py, line 13, in <module> ()
    f.bar()
A debugging session is active.

	Inferior 1 [process 3947] will be killed.

Quit anyway? (y or n) [answered Y; input not from terminal]
:: [   PASS   ] :: Running gdb
:: [   PASS   ] :: File 'output' should not contain 'Error occurred in Python command'
:: [   PASS   ] :: File 'output' should contain 'file .*ctypes.*in.*string_at'
:: [   FAIL   ] :: File 'output' should contain 'file.*test.py.*in.*bar' 
:: [   PASS   ] :: File 'output' should contain 'file.*test.py.*in.*module'

=============================================================================
Additional info:
Pretty output from s390x architecture:

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
:: [   LOG    ] :: Test
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
PyString_FromString (str=0xdeadbeef <Address 0xdeadbeef out of bounds>) at /usr/src/debug/Python-2.7.3/Objects/stringobject.c:121
121	    size = strlen(str);
#9 Frame 0x800e4038, for file /usr/lib64/python2.7/ctypes/__init__.py, line 504, in string_at (ptr=3735928559, size=-1)
    return _string_at(ptr, size)
#13 Frame 0x800da598, for file test.py, line 4, in bar (self=<Foo(someattr=42, someotherattr={'three': [(), (None,), (None, None)], 'two': 2L, 'one': 1}) at remote 0x3fffda40048>, string_at=<function at remote 0x3fffda3fba8>)
    string_at(0xDEADBEEF) # this code will cause Python to segfault
#16 Frame 0x800d9f08, for file test.py, line 13, in <module> ()
    f.bar()
A debugging session is active.

	Inferior 1 [process 4978] will be killed.

Quit anyway? (y or n) [answered Y; input not from terminal]
:: [   PASS   ] :: Running gdb
:: [   PASS   ] :: File 'output' should not contain 'Error occurred in Python command'
:: [   PASS   ] :: File 'output' should contain 'file .*ctypes.*in.*string_at'
:: [   PASS   ] :: File 'output' should contain 'file test.py, line 4, in bar.*someattr=42'
:: [   PASS   ] :: File 'output' should contain 'file test.py, line 13, in <module>'

Comment 4 Petr Šplíchal 2013-02-22 11:15:57 UTC

I guess broken functionality on x86_64 is caused by bug 556975.
However, on RHEL6 we get at least something rather than just
"frame information optimized out", here's the RHEL6 output:

Program received signal SIGSEGV, Segmentation fault.
__strlen_sse2 () at ../sysdeps/x86_64/strlen.S:32
32		movdqu	(%rdi), %xmm1
#10 file '/usr/lib64/python2.6/ctypes/__init__.py', in 'string_at'
#14 file 'test.py', in 'bar'
#17 file 'test.py', in '<module>'
A debugging session is active.

Dave, could we get the same on RHEL7 until bug 556975 is fixed?

Comment 6 Bohuslav "Slavek" Kabrda 2013-07-24 09:58:18 UTC

There is a chance that this may be fixed by fixing https://bugzilla.redhat.com/show_bug.cgi?id=835053, let's wait till that is fixed and then rerun the tests using new build.

Comment 7 Branislav Náter 2013-07-31 13:53:46 UTC

Issue si fixed in python-debug-2.7.5-1.el7

<snip>
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff6d6e631 in __strlen_sse2 () from /lib64/libc.so.6
#10 Frame 0x86c2d0, for file /usr/lib64/python2.7/ctypes/__init__.py, line 504, in string_at (ptr=3735928559, size=-1)
    return _string_at(ptr, size)
#14 Frame 0x686140, for file test.py, line 5, in bar (self=<Foo(someattr=42, someotherattr={'three': [(), (None,), (None, None)], 'two': 2L, 'one': 1}) at remote 0x823600>, string_at=<function at remote 0x884450>)
    string_at(0xDEADBEEF) # this code will cause Python to segfault
#17 Frame 0x85d2b0, for file test.py, line 16, in <module> ()
    f.bar()
A debugging session is active.

	Inferior 1 [process 1476] will be killed.

Quit anyway? (y or n) [answered Y; input not from terminal]
:: [   PASS   ] :: Running gdb
:: [   PASS   ] :: File 'output' should not contain 'Error occurred in Python command'
:: [   PASS   ] :: File 'output' should contain '[fF]ile .*ctypes.*in.*string_at'
:: [   PASS   ] :: File 'output' should contain '[fF]ile.*test.py.*in.*bar'
:: [   PASS   ] :: File 'output' should contain '[fF]ile.*test.py.*in.*module'
</snip>

Comment 8 Ludek Smid 2014-06-13 12:43:36 UTC

This request was resolved in Red Hat Enterprise Linux 7.0.

Contact your manager or support representative in case you have further questions about the request.

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