[Bug libc/13097] New: gdb regression: Excessive linux-vdso.so.1 name

[Bug libc/13097] New: gdb regression: Excessive linux-vdso.so.1 name

[jan.kratochvil at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=13097

             Bug #: 13097
           Summary: gdb regression: Excessive linux-vdso.so.1 name
           Product: glibc
           Version: 2.14
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: drepper.fsp@gmail.com
        ReportedBy: jan.kratochvil@redhat.com
    Classification: Unclassified


Description of problem:
GDB has started to print on each `run':
warning: Could not load shared library symbols for linux-vdso.so.1.
Do you need "set solib-search-path" or "set sysroot"?

Version-Release number of selected component (if applicable):
FAIL: glibc-2.14.90-5.x86_64
PASS: glibc-2.14.90-4.x86_64
Guessing it is due to:
commit 73d7af4f4c2b394063cb0b3a33ee2b00b5ad80b4
    Implement LD_DEBUG=scopes

How reproducible:
Always.

Steps to Reproduce:
echo 'main(){}'|gcc -x c -;../gdb -nx ./a.out -ex start -ex 'info shared' -ex c
-ex q

Actual results:
Starting program: .../a.out 
warning: Could not load shared library symbols for linux-vdso.so.1.
Do you need "set solib-search-path" or "set sysroot"?
Temporary breakpoint 1, 0x0000000000400478 in main ()
>From                To                  Syms Read   Shared Object Library
0x00007ffff7ddbb20  0x00007ffff7df513a  Yes         /lib64/ld-linux-x86-64.so.2
                                        No          linux-vdso.so.1
0x00007ffff7a4adc0  0x00007ffff7b80050  Yes         /lib64/libc.so.6
Continuing.

Expected results:
Starting program: .../a.out 
Temporary breakpoint 1, 0x0000000000400478 in main ()
>From                To                  Syms Read   Shared Object Library
0x00007ffff7ddbb20  0x00007ffff7df4eda  Yes         /lib64/ld-linux-x86-64.so.2
0x00007ffff7a4ad30  0x00007ffff7b7ff60  Yes         /lib64/libc.so.6
Continuing.

Additional info:
glibc vdso had its name in the link map "" before.
I do not see why the name should be different when there is no corresponding
on-disk file for it.  Should GDB ignore for symbol resolution libraries with
literal path-less name "linux-vdso.so.1"?

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[Bug libc/13097] gdb regression: Excessive linux-vdso.so.1 name

[drepper.fsp at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=13097

Ulrich Drepper <drepper.fsp at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |WORKSFORME

--- Comment #1 from Ulrich Drepper <drepper.fsp at gmail dot com> 2011-09-06 01:39:26 UTC ---
Why on earth would you think this is a problem in glibc?  Make gdb handle
whatever glibc does.  You must already have magic code in gdb to handle this
DSO.

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[Bug libc/13097] gdb regression: Excessive linux-vdso.so.1 name

[jan.kratochvil at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=13097

Jan Kratochvil <jan.kratochvil at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Blocks|                            |14466

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[Bug libc/13097] gdb regression: Excessive linux-vdso.so.1 name

[jan.kratochvil at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=13097

Jan Kratochvil <jan.kratochvil at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jan.kratochvil at redhat
                   |                            |dot com

--- Comment #2 from Jan Kratochvil <jan.kratochvil at redhat dot com> 2012-11-24 19:09:46 UTC ---
For the record it is reverted in Fedora rpm glibc-fedora.patch:
In glibc GIT fedora/master branch:
commit 0c95ab64cb4ec0d22bb222647d9d20c7b4903e38
Author: Andreas Schwab <schwab@redhat.com>
Date:   Fri Oct 7 09:31:27 2011 +0200
-             l->l_libname->name = l->l_name = memcpy (copy, dsoname, len);
+             l->l_libname->name = memcpy (copy, dsoname, len);
+             if (GLRO(dl_debug_mask))
+               l->l_name = copy;

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[Bug libc/13097] gdb regression: Excessive linux-vdso.so.1 name

[ldv at altlinux dot org]

http://sourceware.org/bugzilla/show_bug.cgi?id=13097

Dmitry V. Levin <ldv at altlinux dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ldv at altlinux dot org

--- Comment #3 from Dmitry V. Levin <ldv at altlinux dot org> 2012-11-24 21:40:16 UTC ---
That patch(In reply to comment #2)
> For the record it is reverted in Fedora rpm glibc-fedora.patch:

Also for the record, it was later factored out from glibc-fedora.patch as
http://pkgs.fedoraproject.org/cgit/glibc.git/tree/glibc-fedora-elf-rh737223.patch?id=fb633eaa14bb4c2b35f26c6ec2f4d829f27819ac

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[Bug libc/13097] gdb regression: Excessive linux-vdso.so.1 name

[naesten at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=13097

Samuel Bronson <naesten at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
                 CC|                            |naesten at gmail dot com
         Resolution|WORKSFORME                  |---

--- Comment #4 from Samuel Bronson <naesten at gmail dot com> ---
This is still an issue; how could listing a library under a valid but
non-existent filename not confuse tools?

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[Bug libc/13097] gdb regression: Excessive linux-vdso.so.1 name

[carlos at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=13097

Carlos O'Donell <carlos at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |WAITING
                 CC|                            |carlos at redhat dot com

--- Comment #5 from Carlos O'Donell <carlos at redhat dot com> ---
(In reply to Samuel Bronson from comment #4)
> This is still an issue; how could listing a library under a valid but
> non-existent filename not confuse tools?

We aren't likely to get to work on this any time soon. We don't have enough
resources.

The code in question is now in elf/setup-vdso.h, and I would be more than happy
to review a patch that fixes this bug.

You'd need to run the testsuite on master to make sure you don't introduce any
regressions and then show that LD_DEBUG=all still works, and that the debugger
which was previously reporting bogus warnings doesn't report any more bogus
warnings.

The best possible patch avoids this hack:
+             if (GLRO(dl_debug_mask))
+               l->l_name = copy;

and instead adjusts the debug code to inform the user that this DSO has no
associated file e.g. a virtual dso.

Notes:
http://sourceware.org/glibc/wiki/Contribution%20checklist

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[Bug libc/13097] gdb regression: Excessive linux-vdso.so.1 name

[naesten at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=13097

Samuel Bronson <naesten at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|drepper.fsp at gmail dot com       |unassigned at sourceware dot org

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[Bug dynamic-link/13097] gdb regression: Excessive linux-vdso.so.1 name

[jsm28 at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=13097

Joseph Myers <jsm28 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|libc                        |dynamic-link

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[Bug dynamic-link/13097] gdb regression: Excessive linux-vdso.so.1 name

[jackie.rosen at hushmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=13097

Jackie Rosen <jackie.rosen at hushmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jackie.rosen at hushmail dot com

--- Comment #6 from Jackie Rosen <jackie.rosen at hushmail dot com> ---
*** Bug 260998 has been marked as a duplicate of this bug. ***
Seen from the domain http://volichat.com
Page where seen: http://volichat.com/adult-chat-rooms
Marked for reference. Resolved as fixed @bugzilla.

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[Bug dynamic-link/13097] gdb regression: Excessive linux-vdso.so.1 name

[kalvdans at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=13097

chn <kalvdans at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kalvdans at gmail dot com

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[Bug dynamic-link/13097] gdb regression: Excessive linux-vdso.so.1 name

[ovidiu.b13 at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=13097

Ovidiu-Florin Bogdan <ovidiu.b13 at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ovidiu.b13 at gmail dot com

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[Bug dynamic-link/13097] gdb regression: Excessive linux-vdso.so.1 name

[schwab at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=13097

Andreas Schwab <schwab at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|jackie.rosen at hushmail dot com   |

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[Bug dynamic-link/13097] gdb regression: Excessive linux-vdso.so.1 name

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=13097

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
              Flags|                            |security-

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