Hi Matthieu, On 2025-04-29 18:12:29+0200, Matthieu Baerts wrote: > Hi Thomas, Masahiro, > > +Cc Peter Oberparleiter, MPTCP ML > > On 15/03/2025 14:20, Thomas Weißschuh wrote: > > -fmacro-prefix-map only affects __FILE__ and __BASE_FILE__. > > Other references, for example in debug information, are not affected. > > This makes handling of file references in the compiler outputs harder to > > use and creates problems for reproducible builds. > > > > Switch to -ffile-prefix map which affects all references. > > > > Also drop the documentation section advising manual specification of > > -fdebug-prefix-map for reproducible builds, as it is not necessary > > anymore. > > > > Suggested-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> > > Link: https://lore.kernel.org/lkml/c49cc967294f9a3a4a34f69b6a8727a6d3959ed8.camel@xxxxxxxxxxxxxxx/ > > Acked-by: Borislav Petkov (AMD) <bp@xxxxxxxxx> # arch/x86/ > > Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx> > > Thank you for having worked on that! > > (...) > > > diff --git a/Makefile b/Makefile > > index 5c333682dc9142b1aacfe454a5c77f5923554b7d..4f920187cee658ae4d1b807fca365f6994274828 100644 > > --- a/Makefile > > +++ b/Makefile > > @@ -1067,7 +1067,7 @@ endif > > > > # change __FILE__ to the relative path to the source directory > > ifdef building_out_of_srctree > > -KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srcroot)/=) > > +KBUILD_CPPFLAGS += $(call cc-option,-ffile-prefix-map=$(srcroot)/=) > > KBUILD_RUSTFLAGS += --remap-path-prefix=$(srcroot)/= > > endif > > Today, I noticed that my CI for the MPTCP subsystem couldn't produce > code coverage files like before: the source files are not found. A 'git > bisect' pointed me to this patch. Reverting it seems to fix the issue. > > > My CI is building the kernel out of the source tree, in ".virtme/build". > Before and after this patch, GCOV seems to do its job properly. > Capturing GCOV data with this lcov command seems OK too: > > lcov --capture --keep-going -j "${INPUT_CPUS}" \ > --rc geninfo_unexecuted_blocks=1 \ > --include '/net/mptcp/' \ > --function-coverage --branch-coverage \ > -b "${PWD}/.virtme/build" -o kernel.lcov > > But after this patch, lcov complains some files are not found, e.g. > > ERROR: (source) unable to open > ${WORKDIR}/.virtme/build/net/mptcp/ctrl.c: No such file or directory > > > The output file is different: the path to the source file is wrong > because it points to the build dir. Instead of ... > > SF:${WORKDIR}/net/mptcp/ctrl.c > > ... now I have ... > > SF:${WORKDIR}/.virtme/build/net/mptcp/ctrl.c > > > Are there modifications needed on GCOV side to adapt to the behaviour > change introduced by this patch? Or something else needed on the > userspace side? I'd like to focus on the report from Ville Syrjälä [0] first. While it is easier to reproduce and investigate, I suspect the solution found there will also work for your usecase. Thomas [0] https://lore.kernel.org/lkml/aBEttQH4kimHFScx@xxxxxxxxx/
