[Bug dynamic-link/17078] New: error while loading shared libraries: unexpected reloc type 0x0d

[Bug dynamic-link/17078] New: error while loading shared libraries: unexpected reloc type 0x0d

[macro@linux-mips.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17078

            Bug ID: 17078
           Summary: error while loading shared libraries: unexpected reloc
                    type 0x0d
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: dynamic-link
          Assignee: unassigned at sourceware dot org
          Reporter: macro@linux-mips.org
                CC: macro@linux-mips.org
            Target: arm-linux-gnueabi

All the TLS test cases fail in the prelinker test suite when built with
the use of R_ARM_TLS_DESC relocations, that is with the
`-mtls-dialect=gnu2' GCC option in effect.  The following messages are
produced:

./tls1: error while loading shared libraries: unexpected reloc type 0x0d
FAIL: tls1.sh
./tls2: error while loading shared libraries: unexpected reloc type 0x0d
FAIL: tls2.sh
./tls3: error while loading shared libraries: unexpected reloc type 0x0d
FAIL: tls3.sh
./tls4: error while loading shared libraries: unexpected reloc type 0x0d
FAIL: tls4.sh
./tls5: error while loading shared libraries: unexpected reloc type 0x0d
FAIL: tls5.sh
./tls6: error while loading shared libraries: unexpected reloc type 0x0d
FAIL: tls6.sh

The reason is the lack of handling for prelinked R_ARM_TLS_DESC
relocations in the dynamic linker.

Borrowing the testcase from bug #17075 it can also be reproduced as
follows:

$ cat libgetfoo.c
int __thread foo;

int
getfoo (void)
{
  return foo;
}
$ arm-linux-gnueabi-gcc -mtls-dialect=gnu2 -fPIC -shared
-Wl,-dynamic-linker,.../lib/ld-linux.so.3 -Wl,-rpath,.../lib -Wl,-rpath,$(pwd)
-o libgetfoo.so libgetfoo.c
$ cat getfoo.c
int getfoo (void);

int
main (void)
{
  return getfoo ();
}
$ arm-linux-gnueabi-gcc -mtls-dialect=gnu2
-Wl,-dynamic-linker,.../lib/ld-linux.so.3 -Wl,-rpath,.../lib -Wl,-rpath,$(pwd)
-o getfoo -L. -lgetfoo getfoo.c
$ ssh arm-host $(pwd)/getfoo
$ echo $?
0
$ echo .../lib > prelink.conf
$ echo $(pwd) >> prelink.conf
$ arm-linux-gnueabi-prelink -c ./prelink.conf -C ./prelink.cache
--ld-library-path=.../lib:$(pwd) --dynamic-linker=.../lib/ld-linux.so.3 -v
getfoo
Laying out 4 libraries in virtual address space 41000000-50000000
Assigned virtual address space slots for libraries:
.../lib/ld-linux.so.3 41000000-41028954
.../lib/libc.so.6 41030000-4116d588
.../lib/libgcc_s.so.1 41170000-4119832c
$(pwd)/libgetfoo.so 411a0000-411a8910
Prelinking .../lib/ld-2.19.90.so
Prelinking .../lib/libc-2.19.90.so
Prelinking .../lib/libgcc_s.so.1
Prelinking $(pwd)/libgetfoo.so
Prelinking $(pwd)/getfoo
$ ssh arm-host $(pwd)/getfoo
$(pwd)/getfoo: error while loading shared libraries: unexpected reloc type 0x0d
$ echo $?
127
$ 

I have substituted `...' for the sysroot path and $(pwd) for the CWD even
in output to avoid clutter.

The ARM TLS descriptor specification can be referred at bug #17075.

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[Bug dynamic-link/17078] error while loading shared libraries: unexpected reloc type 0x0d

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17078

Florian Weimer <fweimer at redhat dot com> changed:

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

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[Bug dynamic-link/17078] error while loading shared libraries: unexpected reloc type 0x0d

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17078

--- Comment #1 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  9c82da17b5794efebe005de2fd22d61a3ea4b58a (commit)
      from  831b9896d8e957580591a3cbe11dcd5ac6743ba2 (commit)

Those revisions listed above that are new to this repository have
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- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=9c82da17b5794efebe005de2fd22d61a3ea4b58a

commit 9c82da17b5794efebe005de2fd22d61a3ea4b58a
Author: Maciej W. Rozycki <macro@codesourcery.com>
Date:   Thu Jul 17 19:22:05 2014 +0100

    [BZ #17078] ARM: R_ARM_TLS_DESC prelinker support

    This is a change to the dynamic linker to add prelinker support for the
    R_ARM_TLS_DESC relocation.  Two cases can be considered here, the usual
    one where lazy binding is in use and the less frequent one, where
    immediate binding is requested via the use of the DF_BIND_NOW dynamic
    flag (e.g. by using the GNU linker's "-z now" option).

    This change only handles the first case.  In this scenario the prelinker
    does what the dynamic linker would do, that is it preinitialises
    R_ARM_TLS_DESC relocations with a pointer to the lazy specialization as
    provided with the DT_TLSDESC_PLT dynamic tag.  A conflict is
    additionally created and in the conflict resolution path the dynamic
    linker complements the work by initialising the object's pointer as
    indicated by the DT_TLSDESC_GOT dynamic tag to the linker's internal
    lazy specialization worker function and also providing the associated
    link map in the second entry of the GOT.  This step is required, because
    if prelinking is successful at the run time, then the dynamic linker's
    elf_machine_runtime_setup() function isn't called that would normally do
    so.

    The second case remains unresolved, because support for that scenario
    has not been implemented in the prelinker.  In this case the lazy
    specialization is unavailable and the DT_TLSDESC_PLT dynamic tag is not
    present.

    The prelinker could assume the common case of static specialization and
    resolve the relocation, but that would require the exposure of dynamic
    linker's specialization worker function.  Furthermore the dynamic linker
    would have to handle the relocation in the conflict resolution path and
    see if the dynamic specialization should be used instead.  This however
    would require access to data structures currently not made available to
    the conflict resolution path and therefore a redesign of this part of
    the dynamic linker.

    Alternatively the prelinker could defer all processing to the dynamic
    linker's conflict resolution path, but that would require similar access
    to the said data structures.

    Therefore the prelinker issues an error instead and the dynamic linker
    has assertions to check that DT_TLSDESC_PLT and DT_TLSDESC_GOT are in
    use in its conflict resolution path.

    This change resolves all TLS failures in the prelinker testsuite, as
    noted in the bug report, as well as the small test case provided there.
    Unfortunately we don't seem to have any hooks to factor in the prelinker
    (if present on a system) to testing, so at this time this fix has to
    rely on using the prelinker test suite and enabling TLS descriptors
    there for coverage.

        [BZ #17078]
        * sysdeps/arm/dl-machine.h (elf_machine_rela)
        [RESOLVE_CONFLICT_FIND_MAP]: Handle R_ARM_TLS_DESC relocation.
        (elf_machine_lazy_rel): Handle prelinked R_ARM_TLS_DESC entries.

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

Summary of changes:
 ChangeLog                |    7 +++++++
 NEWS                     |    4 ++--
 sysdeps/arm/dl-machine.h |   34 +++++++++++++++++++++++++++++++---
 3 files changed, 40 insertions(+), 5 deletions(-)

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[Bug dynamic-link/17078] error while loading shared libraries: unexpected reloc type 0x0d

[macro@linux-mips.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17078

Maciej W. Rozycki <macro@linux-mips.org> changed:

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

--- Comment #2 from Maciej W. Rozycki <macro@linux-mips.org> ---
Fixed as per the automatically entered commit message.

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