[Bug corefiles/14983] New: GDB 7.5.1 crash due to NULL pointer reference at -break-insert

[Bug corefiles/14983] New: GDB 7.5.1 crash due to NULL pointer reference at -break-insert

[forum at emblocks dot org]

http://sourceware.org/bugzilla/show_bug.cgi?id=14983

             Bug #: 14983
           Summary: GDB 7.5.1 crash due to NULL pointer reference at
                    -break-insert
           Product: gdb
           Version: 7.5
            Status: NEW
          Severity: critical
          Priority: P2
         Component: corefiles
        AssignedTo: unassigned@sourceware.org
        ReportedBy: forum@emblocks.org
    Classification: Unclassified


File: dwarf2read.c
Function:  process_full_comp_unit

Original:

  static_block = end_symtab_get_static_block (highpc + baseaddr, objfile, 0);

  /* If the comp unit has DW_AT_ranges, it may have discontiguous ranges.
     Also, DW_AT_ranges may record ranges not belonging to any child DIEs
     (such as virtual method tables).  Record the ranges in STATIC_BLOCK's
     addrmap to help ensure it has an accurate map of pc values belonging to
     this comp unit.  */

  dwarf2_record_block_ranges (cu->dies, static_block, baseaddr, cu);
  symtab = end_symtab_from_static_block (static_block, objfile,
                                           SECT_OFF_TEXT (objfile), 0);

The pointer static_block can be NULL while iterating through the symbols. this
will cause a crash of GDB.

I have this patched by:

  static_block = end_symtab_get_static_block (highpc + baseaddr, objfile, 0);

  /* If the comp unit has DW_AT_ranges, it may have discontiguous ranges.
     Also, DW_AT_ranges may record ranges not belonging to any child DIEs
     (such as virtual method tables).  Record the ranges in STATIC_BLOCK's
     addrmap to help ensure it has an accurate map of pc values belonging to
     this comp unit.  */

  // NOTE (Gerard#1#): Bug fix!!!!!!
  symtab = NULL; 
  if(static_block ) 
  {
        dwarf2_record_block_ranges (cu->dies, static_block, baseaddr, cu);

        symtab = end_symtab_from_static_block (static_block, objfile,
                                                SECT_OFF_TEXT (objfile), 0);
  }

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[Bug corefiles/14983] GDB 7.5.1 crash due to NULL pointer reference at -break-insert

[forum at emblocks dot org]

http://sourceware.org/bugzilla/show_bug.cgi?id=14983

Gerard Zagema <forum at emblocks dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |forum at emblocks dot org

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[Bug corefiles/14983] GDB 7.5.1 crash due to NULL pointer reference at -break-insert

[tromey at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14983

Tom Tromey <tromey at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tromey at redhat dot com

--- Comment #1 from Tom Tromey <tromey at redhat dot com> 2013-03-06 22:02:49 UTC ---
It would be useful to know how to trigger the bug.

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[Bug corefiles/14983] GDB 7.5.1 crash due to NULL pointer reference at -break-insert

[forum at emblocks dot org]

http://sourceware.org/bugzilla/show_bug.cgi?id=14983

--- Comment #2 from Gerard Zagema <forum at emblocks dot org> 2013-03-07 06:44:24 UTC ---
The bug can be triggered if you take an ARM build and load a file created with
the RealView compiler from ELF.

I could send you such file but you also need another patch to solve another bug
in the same file which takes care of the path separators, a bug which is for
ages in GDB.

The previous versions always go right because the NULL_POINTER was tested and
now it is used without test which will give a crash instantly if I try to set a
breakpoint.

The 7.5.1 version is, with the modifications I did, working fine.

Regards

Gerard

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[Bug corefiles/14983] GDB 7.5.1 crash due to NULL pointer reference at -break-insert

[forum at emblocks dot org]

http://sourceware.org/bugzilla/show_bug.cgi?id=14983

--- Comment #3 from Gerard Zagema <forum at emblocks dot org> 2013-03-07 06:46:18 UTC ---
The bug can be triggered if you take an ARM build and load a file created with
the RealView compiler from ARM.

I could send you such file but you also need another patch to solve another bug
in the same file which takes care of the path separators, a bug which is for
ages in GDB.

The previous versions always go right because the NULL_POINTER was tested and
now it is used without test which will give a crash instantly if I try to set a
breakpoint.

The 7.5.1 version is, with the modifications I did, working fine.

Regards

Gerard

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[Bug corefiles/14983] GDB 7.5.1 crash due to NULL pointer reference at -break-insert

[tromey at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14983

--- Comment #4 from Tom Tromey <tromey at redhat dot com> 2013-03-08 16:03:29 UTC ---
(In reply to comment #3)
> The bug can be triggered if you take an ARM build and load a file created with
> the RealView compiler from ARM.
> 
> I could send you such file but you also need another patch to solve another bug
> in the same file which takes care of the path separators, a bug which is for
> ages in GDB.

If you could attach a small one, that would be helpful.
I am mostly concerned about how to write a regression test for this.
So I'd want to inspect the DWARF to see what is confusing gdb.

Could you please file the path separator thing, plus your patch,
as a separate bug?

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[Bug corefiles/14983] GDB 7.5.1 crash due to NULL pointer reference at -break-insert

[tromey at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14983

Tom Tromey <tromey at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |smarf at gmx dot de

--- Comment #5 from Tom Tromey <tromey at redhat dot com> 2013-04-12 17:44:23 UTC ---
*** Bug 15325 has been marked as a duplicate of this bug. ***

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[Bug corefiles/14983] GDB 7.5.1 crash due to NULL pointer reference at -break-insert

[tromey at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14983

Tom Tromey <tromey at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |Andreas.Kaufmann at gmx dot
                   |                            |de

--- Comment #6 from Tom Tromey <tromey at redhat dot com> 2013-04-12 17:45:35 UTC ---
*** Bug 15343 has been marked as a duplicate of this bug. ***

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[Bug corefiles/14983] GDB 7.5.1 crash due to NULL pointer reference at -break-insert

[tromey at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14983

--- Comment #7 from Tom Tromey <tromey at redhat dot com> 2013-04-12 17:46:02 UTC ---
There is a patch pending:
http://sourceware.org/ml/gdb-patches/2013-04/msg00171.html

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[Bug corefiles/14983] GDB 7.5.1 crash due to NULL pointer reference at -break-insert

[cvs-commit at gcc dot gnu.org]

http://sourceware.org/bugzilla/show_bug.cgi?id=14983

--- Comment #8 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> 2013-04-25 16:25:38 UTC ---
CVSROOT:    /cvs/src
Module name:    src
Changes by:    tromey@sourceware.org    2013-04-25 16:25:37

Modified files:
    gdb            : ChangeLog dwarf2read.c 
    gdb/testsuite  : ChangeLog 
Added files:
    gdb/testsuite/gdb.dwarf2: nostaticblock.exp 

Log message:
    PR corefiles/14983:
    * dwarf2read.c (process_full_comp_unit): Always create a static
    block.
    gdb/testsuite
    * gdb.dwarf2/nostaticblock.exp: New file.

Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/ChangeLog.diff?cvsroot=src&r1=1.15474&r2=1.15475
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/dwarf2read.c.diff?cvsroot=src&r1=1.788&r2=1.789
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/ChangeLog.diff?cvsroot=src&r1=1.3638&r2=1.3639
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/gdb.dwarf2/nostaticblock.exp.diff?cvsroot=src&r1=NONE&r2=1.1

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[Bug corefiles/14983] GDB 7.5.1 crash due to NULL pointer reference at -break-insert

[tromey at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14983

Tom Tromey <tromey at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |7.7

--- Comment #9 from Tom Tromey <tromey at redhat dot com> 2013-04-25 16:27:26 UTC ---
Fix checked in.

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