[Bug dynamic-link/17620] New: DTV_SURPLUS limits loading of Static TLS-requiring modules in multi-threaded programs

[Bug dynamic-link/17620] New: DTV_SURPLUS limits loading of Static TLS-requiring modules in multi-threaded programs

[aoliva at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17620

            Bug ID: 17620
           Summary: DTV_SURPLUS limits loading of Static TLS-requiring
                    modules in multi-threaded programs
           Product: glibc
           Version: 2.21
            Status: NEW
          Severity: normal
          Priority: P2
         Component: dynamic-link
          Assignee: aoliva at sourceware dot org
          Reporter: aoliva at sourceware dot org

elf/dl-open.c has long had this piece of code:

         if (! RTLD_SINGLE_THREAD_P && imap->l_tls_modid > DTV_SURPLUS)
           _dl_signal_error (0, "dlopen", NULL, N_("\
cannot load any more object with static TLS"));

It sets a limit on the modid that a module can have if its TLS area is to be
placed in the Static TLS area.  That's because we initialize Static TLS DTV
entries right away immediately, and this may require growing DTVs if the modid
that indexes the DTV is past the minimum number of entries guaranteed to be
present in every thread's DTV, and we can't grow another thread's DTV safely.

This problem becomes more apparent on platforms that use TLS Descriptors, that
attempt to use Static TLS more often than others, and that did not take modid
into account when deciding whehter or not the attempt can be successful.

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[Bug dynamic-link/17620] DTV_SURPLUS limits loading of Static TLS-requiring modules in multi-threaded programs

[aoliva at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17620

Alexandre Oliva <aoliva at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED

--- Comment #1 from Alexandre Oliva <aoliva at sourceware dot org> ---
Mine, I have a patch.

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[Bug dynamic-link/17620] DTV_SURPLUS limits loading of Static TLS-requiring modules in multi-threaded programs

[david.abdurachmanov at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17620

David Abdurachmanov <david.abdurachmanov at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |david.abdurachmanov at gmail dot c
                   |                            |om

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[Bug dynamic-link/17620] DTV_SURPLUS limits loading of Static TLS-requiring modules in multi-threaded programs

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17620

--- Comment #2 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU C Library master sources".

The branch, master has been updated
       via  f8aeae347377f3dfa8cbadde057adf1827fb1d44 (commit)
      from  b97eb2bdb1ed72982a7821c3078be591051cef59 (commit)

Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
revisions in full, below.

- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=f8aeae347377f3dfa8cbadde057adf1827fb1d44

commit f8aeae347377f3dfa8cbadde057adf1827fb1d44
Author: Alexandre Oliva <aoliva@redhat.com>
Date:   Tue Mar 17 01:14:11 2015 -0300

    Fix DTV race, assert, DTV_SURPLUS Static TLS limit, and nptl_db garbage

    for  ChangeLog

        [BZ #17090]
        [BZ #17620]
        [BZ #17621]
        [BZ #17628]
        * NEWS: Update.
        * elf/dl-tls.c (_dl_update_slotinfo): Clean up outdated DTV
        entries with Static TLS too.  Skip entries past the end of the
        allocated DTV, from Alan Modra.
        (tls_get_addr_tail): Update to glibc_likely/unlikely.  Move
        Static TLS DTV entry set up from...
         (_dl_allocate_tls_init): ... here (fix modid assertion), ...
        * elf/dl-reloc.c (_dl_nothread_init_static_tls): ... here...
        * nptl/allocatestack.c (init_one_static_tls): ... and here...
        * elf/dlopen.c (dl_open_worker): Drop l_tls_modid upper bound
        for Static TLS.
        * elf/tlsdeschtab.h (map_generation): Return size_t.  Check
        that the slot we find is associated with the given map before
        using its generation count.
        * nptl_db/db_info.c: Include ldsodefs.h.
        (rtld_global, dtv_slotinfo_list, dtv_slotinfo): New typedefs.
        * nptl_db/structs.def (DB_RTLD_VARIABLE): New macro.
        (DB_MAIN_VARIABLE, DB_RTLD_GLOBAL_FIELD): Likewise.
        (link_map::l_tls_offset): New struct field.
        (dtv_t::counter): Likewise.
        (rtld_global): New struct.
        (_rtld_global): New rtld variable.
        (dl_tls_dtv_slotinfo_list): New rtld global field.
        (dtv_slotinfo_list): New struct.
        (dtv_slotinfo): Likewise.
        * nptl_db/td_symbol_list.c: Drop gnu/lib-names.h include.
        (td_lookup): Rename to...
        (td_mod_lookup): ... this.  Use new mod parameter instead of
        LIBPTHREAD_SO.
        * nptl_db/td_thr_tlsbase.c: Include link.h.
        (dtv_slotinfo_list, dtv_slotinfo): New functions.
        (td_thr_tlsbase): Check DTV generation.  Compute Static TLS
        addresses even if the DTV is out of date or missing them.
        * nptl_db/fetch-value.c (_td_locate_field): Do not refuse to
        index zero-length arrays.
        * nptl_db/thread_dbP.h: Include gnu/lib-names.h.
        (td_lookup): Make it a macro implemented in terms of...
        (td_mod_lookup): ... this declaration.
        * nptl_db/db-symbols.awk (DB_RTLD_VARIABLE): Override.
        (DB_MAIN_VARIABLE): Likewise.

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                |   47 +++++++++++++
 NEWS                     |   11 ++--
 elf/dl-open.c            |   12 +---
 elf/dl-reloc.c           |    6 --
 elf/dl-tls.c             |   63 +++++++++--------
 elf/tlsdeschtab.h        |    4 +-
 nptl/allocatestack.c     |    9 +--
 nptl_db/db-symbols.awk   |    2 +
 nptl_db/db_info.c        |    4 +
 nptl_db/fetch-value.c    |    3 +-
 nptl_db/structs.def      |   39 +++++++++++
 nptl_db/td_symbol_list.c |    7 +-
 nptl_db/td_thr_tlsbase.c |  172 +++++++++++++++++++++++++++++++++++++++++++++-
 nptl_db/thread_dbP.h     |   11 ++--
 14 files changed, 317 insertions(+), 73 deletions(-)

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[Bug dynamic-link/17620] DTV_SURPLUS limits loading of Static TLS-requiring modules in multi-threaded programs

[aoliva at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17620

Alexandre Oliva <aoliva at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #3 from Alexandre Oliva <aoliva at sourceware dot org> ---
Fixed

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[Bug dynamic-link/17620] DTV_SURPLUS limits loading of Static TLS-requiring modules in multi-threaded programs

[schwab@linux-m68k.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17620

Andreas Schwab <schwab@linux-m68k.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Depends on|                            |18457


Referenced Bugs:

https://sourceware.org/bugzilla/show_bug.cgi?id=18457
[Bug 18457] pthread_join deadlock in library destructor
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[Bug dynamic-link/17620] DTV_SURPLUS limits loading of Static TLS-requiring modules in multi-threaded programs

[siddhesh at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17620
Bug 17620 depends on bug 18457, which changed state.

Bug 18457 Summary: pthread_join deadlock in library destructor
https://sourceware.org/bugzilla/show_bug.cgi?id=18457

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

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