• Fredrik Noring's avatar
    kbuild: modversions: Fix relative CRC byte order interpretation · aa7f29f8
    Fredrik Noring authored
    commit 54a7151b upstream.
    
    Fix commit 56067812 ("kbuild: modversions: add infrastructure for
    emitting relative CRCs") where CRCs are interpreted in host byte order
    rather than proper kernel byte order. The bug is conditional on
    CONFIG_MODULE_REL_CRCS.
    
    For example, when loading a BE module into a BE kernel compiled with a LE
    system, the error "disagrees about version of symbol module_layout" is
    produced. A message such as "Found checksum D7FA6856 vs module 5668FAD7"
    will be given with debug enabled, which indicates an obvious endian
    problem within __kcrctab within the kernel image.
    
    The general solution is to use the macro TO_NATIVE, as is done in
    similar cases throughout modpost.c. With this correction it has been
    verified that a BE kernel compiled with a LE system accepts BE modules.
    
    This change has also been verified with a LE kernel compiled with a LE
    system, in which case TO_NATIVE returns its value unmodified since the
    byte orders match. This is by far the common case.
    
    Fixes: 56067812 ("kbuild: modversions: add infrastructure for emitting relative CRCs")
    Signed-off-by: default avatarFredrik Noring <noring@nocrew.org>
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    aa7f29f8
modpost.c 65.6 KB