Hi Nick, On Thu, 3 Aug 2023 13:50:02 -0700 Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote: > 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... Actually, even with DWARFv5, if I use newer clang, pahole succeded to make BTF info. So it may depend on compiler version too. > > 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. Yeah, it seems a different issue. I could build it at least. Thank you, > > > > > 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 -- Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
