Messages in this thread | | | Date | Wed, 14 Oct 2020 15:50:28 -0700 | From | Kees Cook <> | Subject | Re: [PATCH v6 14/25] kbuild: lto: remove duplicate dependencies from .mod files |
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On Mon, Oct 12, 2020 at 05:31:52PM -0700, Sami Tolvanen wrote: > With LTO, llvm-nm prints out symbols for each archive member > separately, which results in a lot of duplicate dependencies in the > .mod file when CONFIG_TRIM_UNUSED_SYMS is enabled. When a module > consists of several compilation units, the output can exceed the > default xargs command size limit and split the dependency list to > multiple lines, which results in used symbols getting trimmed. > > This change removes duplicate dependencies, which will reduce the > probability of this happening and makes .mod files smaller and > easier to read. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > Reviewed-by: Kees Cook <keescook@chromium.org>
Hi Masahiro,
This appears to be a general improvement as well. This looks like it can land without depending on the rest of the series.
-Kees
> --- > scripts/Makefile.build | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > index ab0ddf4884fd..96d6c9e18901 100644 > --- a/scripts/Makefile.build > +++ b/scripts/Makefile.build > @@ -266,7 +266,7 @@ endef > > # List module undefined symbols (or empty line if not enabled) > ifdef CONFIG_TRIM_UNUSED_KSYMS > -cmd_undef_syms = $(NM) $< | sed -n 's/^ *U //p' | xargs echo > +cmd_undef_syms = $(NM) $< | sed -n 's/^ *U //p' | sort -u | xargs echo > else > cmd_undef_syms = echo > endif > -- > 2.28.0.1011.ga647a8990f-goog >
-- Kees Cook
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