[Bug libc/19826] invalid pointer returned from __tls_get_addr with static linking

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https://sourceware.org/bugzilla/show_bug.cgi?id=19826

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https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=17af5da98cd2c9ec958421ae2108f877e0945451

commit 17af5da98cd2c9ec958421ae2108f877e0945451
Author: Alexandre Oliva <aoliva@redhat.com>
Date:   Wed Sep 21 22:01:16 2016 -0300

    [PR19826] fix non-LE TLS in static programs

    An earlier fix for TLS dropped early initialization of DTV entries for
    modules using static TLS, leaving it for __tls_get_addr to set them
    up.  That worked on platforms that require the GD access model to be
    relaxed to LE in the main executable, but it caused a regression on
    platforms that allow GD in the main executable, particularly in
    statically-linked programs: they use a custom __tls_get_addr that does
    not update the DTV, which fails when the DTV early initialization is
    not performed.

    In static programs, __libc_setup_tls performs the DTV initialization
    for the main thread, but the DTV of other threads is set up in
    _dl_allocate_tls_init, so that's the fix that matters.

    Restoring the initialization in the remaining functions modified by
    this patch was just for uniformity.  It's not clear that it is ever
    needed: even on platforms that allow GD in the main executable, the
    dynamically-linked version of __tls_get_addr would set up the DTV
    entries, even for static TLS modules, while updating the DTV counter.

    for  ChangeLog

        [BZ #19826]
        * elf/dl-tls.c (_dl_allocate_tls_init): Restore DTV early
        initialization of static TLS entries.
        * elf/dl-reloc.c (_dl_nothread_init_static_tls): Likewise.
        * nptl/allocatestack.c (init_one_static_tls): Likewise.

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

Summary of changes:
 ChangeLog            |    8 ++++++++
 elf/dl-reloc.c       |    6 ++++++
 elf/dl-tls.c         |    4 ++++
 nptl/allocatestack.c |    9 ++++++---
 4 files changed, 24 insertions(+), 3 deletions(-)

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