• Rusty Russell's avatar
    module: trim exception table on init free. · ad6561df
    Rusty Russell authored
    It's theoretically possible that there are exception table entries
    which point into the (freed) init text of modules.  These could cause
    future problems if other modules get loaded into that memory and cause
    an exception as we'd see the wrong fixup.  The only case I know of is
    kvm-intel.ko (when CONFIG_CC_OPTIMIZE_FOR_SIZE=n).
    
    Amerigo fixed this long-standing FIXME in the x86 version, but this
    patch is more general.
    
    This implements trim_init_extable(); most archs are simple since they
    use the standard lib/extable.c sort code.  Alpha and IA64 use relative
    addresses in their fixups, so thier trimming is a slight variation.
    
    Sparc32 is unique; it doesn't seem to define ARCH_HAS_SORT_EXTABLE,
    yet it defines its own sort_extable() which overrides the one in lib.
    It doesn't sort, so we have to mark deleted entries instead of
    actually trimming them.
    Inspired-by: 's avatarAmerigo Wang <amwang@redhat.com>
    Signed-off-by: 's avatarRusty Russell <rusty@rustcorp.com.au>
    Cc: linux-alpha@vger.kernel.org
    Cc: sparclinux@vger.kernel.org
    Cc: linux-ia64@vger.kernel.org
    ad6561df
extable.c 2.43 KB