Bug 556944

Summary:

semantic error: No cfa_ops supplied, but needed by DW_OP_call_frame_cfa

Product:

[Fedora] Fedora

Reporter:

Dave Malcolm <dmalcolm>

Component:

systemtap

Assignee:

Mark Wielaard <mjw>

Status:

CLOSED CURRENTRELEASE

QA Contact:

Fedora Extras Quality Assurance <extras-qa>

Severity:

medium

Docs Contact:

Priority:

low

Version:

CC:

dsmith, fche, jistone, mjw, roland, wcohen

Target Milestone:

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Target Release:

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Hardware:

All

OS:

Linux

Whiteboard:

Fixed In Version:

Doc Type:

Bug Fix

Doc Text:

Story Points:

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Clone Of:

Environment:

Last Closed:

2010-02-19 09:17:50 UTC

Type:

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Regression:

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Mount Type:

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Documentation:

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CRM:

Verified Versions:

Category:

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oVirt Team:

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RHEL 7.3 requirements from Atomic Host:

Cloudforms Team:

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Target Upstream Version:

Embargoed:

Bug Depends On:

563528

Bug Blocks:

546295

Attachments:

Description	Flags
/usr/lib/libpython2.6.so.1.0 that's showing this	none
.debug file	none

Description Dave Malcolm 2010-01-19 21:38:09 UTC

Description of problem:
From https://bugzilla.redhat.com/show_bug.cgi?id=546006#c5
> > I'm also sometimes seeing error messages in pass 1 of the
> > form:
> >   semantic error: No cfa_ops supplied, but needed by DW_OP_call_frame_cfa
> > when I make the script more complex; should I file that as a separate bug?

> Yes please, if you see it after updating to systemtap-1.1.
> There has been one bug fix for 1.1 that addresses one case of
> DW_OP_call_frame_cfa not being found, but there seems to be some other issue
> lurking out there. If you get anything with a good reproducer that would b
> very appreciated.    

I'm seeing this with systemtap-1.1-1.fc12.i686, trying to instrument python.

Simplified script is:
probe process("/usr/lib/libpython2.6.so.1.0").function("PyObject_Malloc") {
  printf("PyObject_Malloc(%i)\n", $nbytes);
}

$ stap python-mem-simplified.stp -c "python -c 'import gtk; import dbus'"
semantic error: No cfa_ops supplied, but needed by DW_OP_call_frame_cfa: identifier '$nbytes' at python-mem-simplified.stp:2:35
        source:   printf("PyObject_Malloc(%i)\n", $nbytes);
                                                  ^
Pass 2: analysis failed.  Try again with another '--vp 01' option.

$ stap -vvvv python-mem-simplified.stp -c "python -c 'import gtk; import dbus'"
SystemTap translator/driver (version 1.1/0.143 non-git sources)
Copyright (C) 2005-2009 Red Hat, Inc. and others
This is free software; see the source for copying conditions.
Session arch: i386 release: 2.6.31.9-174.fc12.i686.PAE
Created temporary directory "/tmp/staprQVQaC"
Parsed kernel "/lib/modules/2.6.31.9-174.fc12.i686.PAE/build/.config", number of tuples: 3260
Searched "/usr/share/systemtap/tapset/i386/*.stp", found 3
Searched "/usr/share/systemtap/tapset/*.stp", found 62
Pass 1: parsed user script and 65 library script(s) using 20104virt/12264res/2076shr kb, in 220usr/10sys/285real ms.
dwarf_builder::build for /usr/lib/libpython2.6.so.1.0
parsed 'PyObject_Malloc', func 'PyObject_Malloc'
pattern '/usr/lib/libpython2.6.so.1.0' matches module '/usr/lib/libpython2.6.so.1.0'
focused on module '/usr/lib/libpython2.6.so.1.0 = [0x4eea000-0x5078b6c, bias 0x0] file /usr/lib/debug/usr/lib/libpython2.6.so.1.0.debug ELF machine i?86|x86_64 (code 3)
focused on module '/usr/lib/libpython2.6.so.1.0'
selected function PyObject_Malloc
prologue searching function 'PyObject_Malloc' 0x6c000-0x6c642@Objects/obmalloc.c:724
checking line record 0x6c000@Objects/obmalloc.c:725
prologue found function 'PyObject_Malloc' (naked) = 0x6c000
probe PyObject_Malloc@Objects/obmalloc.c:724 process=/usr/lib/libpython2.6.so.1.0 reloc=.dynamic pc=0x6c000
entry-pc lookup (dwarf_entrypc dieoffset: 0x51118) = 0x6c000 (rc 0)
finding location for local 'nbytes' near address 0x6c000, module bias 0x4eea000
get_cfa_ops @0x6c000, module_start @0x4eea000
dwfl_module_dwarf_cfi failed: no error
got eh cfi bias: 0x10000
dwarf_cfi_addrframe failed: no matching address range
not found cfa
dwarf_builder releasing user dwflpp /usr/lib/libpython2.6.so.1.0
Eliding side-effect-free singleton block operator '{' at python-mem-simplified.stp:1:75
Resolution problem with probe probe_1905
printf("PyObject_Malloc(%i)\\n", $nbytes)
semantic error: No cfa_ops supplied, but needed by DW_OP_call_frame_cfa: identifier '$nbytes' at python-mem-simplified.stp:2:35
        source:   printf("PyObject_Malloc(%i)\n", $nbytes);
                                                  ^
Pass 2: analyzed script: 1 probe(s), 0 function(s), 0 embed(s), 0 global(s) using 25260virt/15548res/4104shr kb, in 40usr/10sys/86real ms.
Pass 2: analysis failed.  Try again with another '--vp 01' option.
Running rm -rf /tmp/staprQVQaC
Spawn waitpid result (0x802): 0

Comment 1 Dave Malcolm 2010-01-19 21:48:59 UTC

Created attachment 385528 [details]
/usr/lib/libpython2.6.so.1.0 that's showing this

Comment 2 Dave Malcolm 2010-01-19 21:49:56 UTC

Created attachment 385530 [details]
.debug file

Comment 3 Mark Wielaard 2010-01-19 21:59:33 UTC

Replicated against:

python-2.6.2-2.fc12.i686
systemtap-1.1-1.fc12.i686

[mark@fedora32 ~]$ stap -e 'probe
process("/usr/lib/libpython2.6.so.1.0").function("PyObject_Malloc")
{printf("PyObject_Malloc(%i)\n", $nbytes);}'
semantic error: No cfa_ops supplied, but needed by DW_OP_call_frame_cfa:
identifier '$nbytes' at <input>:1:108
        source: probe
process("/usr/lib/libpython2.6.so.1.0").function("PyObject_Malloc")
{printf("PyObject_Malloc(%i)\n", $nbytes);}
                                                                               
                                           ^
Pass 2: analysis failed.  Try again with another '--vp 01' option.

Also fails against current systemtap git-trunk.

Comment 4 Mark Wielaard 2010-01-20 09:39:37 UTC

For the record, doesn't fail on x86_64.

Comment 5 Mark Wielaard 2010-02-02 12:55:23 UTC

Fixed upstream:

commit 87748e2b87e574d3c83866ccd0d83678c3c68d93
Author: Mark Wielaard <mjw>
Date:   Tue Feb 2 13:47:19 2010 +0100

    Make sure cfa_ops are always retrieved through dwfl global address.
    
    dwflpp::translate_location() works on the dw address space, but
    get_cfa_ops() starts out with dwfl calls (only dwarf_cfi_addrframe()
    needs to be adjusted for bias).
    
    * dwflpp.cxx (translate_location): Pass pc plus module bias through to
      get_cfa_ops.
      (get_cfa_ops): Adjust for bias when calling dwarf_cfi_addrframe(),
      add frame start/end address when found if verbose logging.
    * testsuite/systemtap.exelib/lib.stp: Add $foo and $bar variables to
      process.function probes.
    * testsuite/systemtap.exelib/libmarkunamestack.stp: Likewise.
    * testsuite/systemtap.exelib/lib.tcl: Expect correct values for
      process.function probe variables.
    * testsuite/systemtap.exelib/libmarkunamestack.tcl: Likewise.

Comment 6 Mark Wielaard 2010-02-10 14:29:03 UTC

The patch in comment #5 relies on an elfutils fix for bug #563528

Comment 7 Mark Wielaard 2010-02-19 09:17:50 UTC

systemtap-1.1-2.fc13 and systemtap-1.1-2.fc12 have been pushed with the fix from comment #5. Which should fix this issue mostly. Full fix will be when new elfutils 0.145 lands (any day now).