On Thu, Aug 3, 2023 at 1:39 PM Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote: > > Em Thu, Aug 03, 2023 at 11:02:46AM -0700, Nick Desaulniers escreveu: > > Hi Martin (and BTF/BPF team), > > I've observed 2 user reports with the error from the subject of this email. > > https://github.com/ClangBuiltLinux/linux/issues/1825 > > https://bbs.archlinux.org/viewtopic.php?id=284177 > > > > Any chance you could take a look at these reports and help us figure > > out what's going wrong here? Nathan and I haven't been able to > > reproduce, but this seems to be affecting OpenMandriva (and Tomasz). > > > > Sounds like perhaps llvm-objcopy vs gnu objcopy might be a relevant detail? > > Masami had a problem with new versions of compilers that was solved > with: > > ------------------------ 8< -------------------------------------------- > > To check that please tweak: > > > > ⬢[acme@toolbox perf-tools-next]$ grep DWARF ../build/v6.2-rc5+/.config > > CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y > > # CONFIG_DEBUG_INFO_DWARF4 is not set > > # CONFIG_DEBUG_INFO_DWARF5 is not set > > ⬢[acme@toolbox perf-tools-next]$ > > > > i.e. disable CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT and enable > > CONFIG_DEBUG_INFO_DWARF4. > > Hm, with CONFIG_DEBUG_INFO_DWARF4, no warning were shown. Downgrading from the now-6-year-old DWARFv5 to now-13-year-old DWARFv4 is not what I'd consider a fix. Someday we can move to DWARFv5...someday... What you describe sounds like build success, but reduction in debug info. The reports I'm referring to seem to result in a build failure. > > LD .tmp_vmlinux.btf > BTF .btf.vmlinux.bin.o > LD .tmp_vmlinux.kallsyms1 > > And > > / # strings /sys/kernel/btf/vmlinux | wc -l > 89921 > / # strings /sys/kernel/btf/vmlinux | grep -w kfree > kfree > > It seems the BTF is correctly generated. (with DWARF5, the number of symbols > are about 30000.) -- Thanks, ~Nick Desaulniers
