Thanks Masami, so that explains why a lot of these warnings come out just after we upgrading to gcc-7.3 (now the objdump version is 2.30). Currently we've already ignore these warnings and won't send this report.
>-----Original Message----- >From: kbuild-all [mailto:[email protected]] On Behalf Of Masami >Hiramatsu >Sent: Thursday, February 8, 2018 10:34 PM >To: Wu, Fengguang <[email protected]> >Cc: Ingo Molnar <[email protected]>; [email protected]; linux- >[email protected] >Subject: Re: [kbuild-all] arch/x86/tools/insn_decoder_test: warning: >ffffffff810005ac: >0f ff e9 ud0 %ecx, %ebp > >On Thu, 8 Feb 2018 06:04:45 +0800 >kbuild test robot <[email protected]> wrote: > >> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git >> master >> head: 7590e37bdaeec25ae325f4ba450be13e2aac6c8d >> commit: 10c91577d5e631773a6394e14cf60125389b71ae x86/tools: Standardize >output format of insn_decode_test >> date: 8 weeks ago >> config: x86_64-randconfig-s2-02072130 (attached as .config) >> compiler: gcc-6 (Debian 6.4.0-9) 6.4.0 20171026 >> reproduce: >> git checkout 10c91577d5e631773a6394e14cf60125389b71ae >> # save the attached .config to linux build tree >> make ARCH=x86_64 >> >> All warnings (new ones prefixed by >>): >> >> arch/x86/tools/insn_decoder_test: warning: Found an x86 instruction >> decoder bug, >please report this. >> >> arch/x86/tools/insn_decoder_test: warning: ffffffff810005ac: 0f ff e9 > ud0 %ecx,%ebp > >Does UD0 really take an operand? Hmm, indeed, the latest Intel SDM >(December2017) >says > >NOTES: >1. Some older processors decode the UD0 instruction without a ModR/M byte. As a >result, those processors would deliver an invalid- >opcode exception instead of a fault on instruction fetch when the instruction >with a >ModR/M byte (and any implied bytes) would >cross a page or segment boundary. > >and older SDM (e.g. March 2017) says UD0 has no modrm byte. >It is easy to change x86-opecode-map.txt, but this means this test may fail >with older >objdump... > >> >> --- >> 0-DAY kernel test infrastructure Open Source Technology Center >> https://lists.01.org/pipermail/kbuild-all Intel Corporation > > >-- >Masami Hiramatsu <[email protected]> >_______________________________________________ >kbuild-all mailing list >[email protected] >https://lists.01.org/mailman/listinfo/kbuild-all
