Re: [lkp] [x86] 784d5699ed: kmsg.ip_tables:no_symbol_version_for_copy_from_user

From: Mathieu OTHACEHE
Date: Sun Oct 09 2016 - 05:46:19 EST


> Do we have any resolution of this?

I got the exact same problem if CONFIG_MODVERSIONS is enabled.
Here is my understanding.

All the symbols exported using assembler macro EXPORT_SYMBOL will need a
__crc_<symbol> to be defined later on (include/asm-generic/export.h).

This is what genksyms should do but it only runs on *.c files. So all the
symbols exported from *.S files won't get crc.

modpost is complaining about missing crc and it will not include those
symbols in *.mod.c modversion_info struct. Then, we got "Unknown
symbol" errors when modules are inserted at runtime.

I fixed it locally by setting __crc_<symbol> to a constant value in
export.h. But it may be a better idea to have genksyms run on *.S files ?