2018-03-30 3:01 GMT+09:00 Laura Abbott <labbott@xxxxxxxxxx>: > Hi, > > This is v2 of my proposal to allow unique build-ids in the kernel. from > last time: > > "" > In Fedora, the debug information is packaged separately (foo-debuginfo) and > can be installed separately. There's been a long standing issue where only one > version of a debuginfo info package can be installed at a time. Mark Wielaard > made an effort for Fedora 27 to allow parallel installation of debuginfo (see > https://fedoraproject.org/wiki/Changes/ParallelInstallableDebuginfo for > more details) > > Part of the requirement to allow this to work is that build ids are > unique between builds. The existing upstream rpm implementation ensures > this by re-calculating the build-id using the version and release as a > seed. This doesn't work 100% for the kernel because of the vDSO which is > its own binary and doesn't get updated. After poking holes in a few of my > ideas, there was a discussion with some people from the binutils team about > adding --build-id-salt to let ld do the calculation debugedit is doing. There > was a counter proposal made about adding some extra information via a .comment > which will affect the build id calculation but just get stripped out. > "" I think you already know '--build-id=uuid' linker option. Doesn't this solve your problem? The disadvantage of this option is, we will lose reproducible building because --build-id=uuid adds every time random salt. The advantage is, the implementation is even simpler, and easier to migrate to --build-id-salt once it is supported in the future. > This v2 cleans up the naming to be consistent and also switches to a > config option vs. an environment variable. I've seen some sporadic > failures about missing the generated header so I think I'm still missing > a dependency somewhere. Right. There is no dependency between 'prepare' and 'scripts' in the top Makefile. Therefore, Kbuild can run them simultaneously, which would cause a race in parallel building. I'm still mostly looking for feedback whether > this would be acceptable for merging or if we should just persue a > --build-id-salt in binutils. > > Thanks, > Laura > > > Laura Abbott (3): > kbuild: Introduce build-salt generated header > kbuild: Link with generated build-salt header > x86/vdso: Add build salt to the vDSO > > Makefile | 13 +++++++++++-- > arch/x86/entry/vdso/vdso-layout.lds.S | 3 +++ > init/Kconfig | 8 ++++++++ > scripts/.gitignore | 1 + > scripts/Makefile | 2 +- > scripts/build-salt.lds.S | 5 +++++ > scripts/gensalt | 21 +++++++++++++++++++++ > scripts/link-vmlinux.sh | 3 ++- > 8 files changed, 52 insertions(+), 4 deletions(-) > create mode 100644 scripts/build-salt.lds.S > create mode 100755 scripts/gensalt > > -- > 2.16.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
