[Bug nptl/27744] New: Support different libpthread/ld.so load orders in libthread_db

[Bug nptl/27744] New: Support different libpthread/ld.so load orders in libthread_db

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27744

            Bug ID: 27744
           Summary: Support different libpthread/ld.so load orders in
                    libthread_db
           Product: glibc
           Version: 2.33
            Status: NEW
          Severity: normal
          Priority: P2
         Component: nptl
          Assignee: unassigned at sourceware dot org
          Reporter: fweimer at redhat dot com
                CC: drepper.fsp at gmail dot com
  Target Milestone: ---

This commit:

commit 1daccf403b1bd86370eb94edca794dc106d02039
Author: Florian Weimer <fweimer@redhat.com>
Date:   Mon Nov 16 19:33:30 2020 +0100

    nptl: Move stack list variables into _rtld_global

    Now __thread_gscope_wait (the function behind THREAD_GSCOPE_WAIT,
    formerly __wait_lookup_done) can be implemented directly in ld.so,
    eliminating the unprotected GL (dl_wait_lookup_done) function
    pointer.

    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

exposed a GDB limitation: libthread_db is loaded once GDB encounters
libpthread, and at this point, ld.so may not have been loaded yet. As a result,
_rtld_global cannot be accessed by regular means from libthread_db.

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[Bug nptl/27744] Support different libpthread/ld.so load orders in libthread_db

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27744

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at sourceware dot org   |fweimer at redhat dot com
                 CC|                            |fweimer at redhat dot com
             Status|NEW                         |ASSIGNED

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[Bug nptl/27744] Support different libpthread/ld.so load orders in libthread_db

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27744

--- Comment #1 from Florian Weimer <fweimer at redhat dot com> ---
Patch posted:
https://sourceware.org/pipermail/libc-alpha/2021-April/125137.html

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[Bug nptl/27744] Support different libpthread/ld.so load orders in libthread_db

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=27744

--- Comment #2 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Florian Weimer <fw@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=a64afc225240b2b27129ccfb0516d7c958b98040

commit a64afc225240b2b27129ccfb0516d7c958b98040
Author: Florian Weimer <fweimer@redhat.com>
Date:   Wed Apr 21 11:50:43 2021 +0200

    nptl_db: Support different libpthread/ld.so load orders (bug 27744)

    libthread_db is loaded once GDB encounters libpthread, and at this
    point, ld.so may not have been processed by GDB yet. As a result,
    _rtld_global cannot be accessed by regular means from libthread_db.
    To make this work until GDB can be fixed, acess _rtld_global through
    a pointer stored in libpthread.

    The new test does not reproduce bug 27744 with
    --disable-hardcoded-path-in-tests, but is still a valid smoke test.
    With --enable-hardcoded-path-in-tests, it is necessary to avoid
    add-symbol-file because this can tickle a GDB bug.

    Fixes commit 1daccf403b1bd86370eb94edca794dc106d02039 ("nptl: Move
    stack list variables into _rtld_global").

    Tested-by: Emil Velikov <emil.velikov@collabora.com>

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[Bug nptl/27744] Support different libpthread/ld.so load orders in libthread_db

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27744

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
   Target Milestone|---                         |2.34
             Status|ASSIGNED                    |RESOLVED

--- Comment #3 from Florian Weimer <fweimer at redhat dot com> ---
Fixed for glibc 2.34.

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[Bug nptl/27744] Support different libpthread/ld.so load orders in libthread_db

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27744

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://sourceware.org/bugz
                   |                            |illa/show_bug.cgi?id=27772

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[Bug nptl/27744] Support different libpthread/ld.so load orders in libthread_db

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=27744

--- Comment #4 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The release/2.33/master branch has been updated by Florian Weimer
<fw@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=ea299b62e83cc38b0d910bbd1a879f7d1f836e96

commit ea299b62e83cc38b0d910bbd1a879f7d1f836e96
Author: Florian Weimer <fweimer@redhat.com>
Date:   Wed Apr 21 11:50:43 2021 +0200

    nptl_db: Support different libpthread/ld.so load orders (bug 27744)

    libthread_db is loaded once GDB encounters libpthread, and at this
    point, ld.so may not have been processed by GDB yet. As a result,
    _rtld_global cannot be accessed by regular means from libthread_db.
    To make this work until GDB can be fixed, acess _rtld_global through
    a pointer stored in libpthread.

    The new test does not reproduce bug 27744 with
    --disable-hardcoded-path-in-tests, but is still a valid smoke test.
    With --enable-hardcoded-path-in-tests, it is necessary to avoid
    add-symbol-file because this can tickle a GDB bug.

    Fixes commit 1daccf403b1bd86370eb94edca794dc106d02039 ("nptl: Move
    stack list variables into _rtld_global").

    Tested-by: Emil Velikov <emil.velikov@collabora.com>
    (cherry picked from commit a64afc225240b2b27129ccfb0516d7c958b98040)

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[Bug nptl/27744] Support different libpthread/ld.so load orders in libthread_db

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=27744

Tom de Vries <vries at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://sourceware.org/bugz
                   |                            |illa/show_bug.cgi?id=27526
                 CC|                            |vries at gcc dot gnu.org

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