Messages in this thread |  | | From | Mathieu OTHACEHE <> | Subject | Re: [lkp] [x86] 784d5699ed: kmsg.ip_tables:no_symbol_version_for_copy_from_user | Date | Fri, 14 Oct 2016 09:27:25 +0200 |
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Hi Michal,
Sorry for late reply. My toolchain in arch linux gcc version 6.2.1 20160830. I used defconfig (x86_64), with CONFIG_MODVERSIONS=y.
I'm understanding better what's happening here. Running:
nm arch/x86/lib/clear_page_64.o gives, 0000000000000000 T clear_page 0000000000000050 T clear_page_c_e 0000000000000010 T clear_page_orig w __crc_clear_page 0000000000000000 r __kcrctab_clear_page 0000000000000000 r __kstrtab_clear_page 0000000000000000 R __ksymtab_clear_page
but running
nm vmlinux|grep __crc_clear_page gives, 0000000051fac2d3 A __crc_clear_page_dirty_for_io
So the weak symbol "__crc_clear_page" is not copied in vmlinux during linking. modpost uses __crc_* symbols to extract crc. Not founding those crc, it doesn't include symbols in mod.c modversion_info struct.
It seems to be a linker bug. I also tested linking: <main.c> int main() { return 0; }
and <test.S> .section test,"a" __kcrctab_test: .quad __test .weak __test
Linking main.o and test.o, * weak symbol "__test" appears in a.out with gcc 5.4.0 * weak symbol "__test" *does not* appear in a.out with gcc 6.2.1
I'll try to find if there is a related bug report in gcc.
Thanks,
Mathieu
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