On Thu, Jan 21, 2021 at 6:07 PM Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote: > > On Thu, Jan 21, 2021 at 9:53 PM Andrii Nakryiko > <andrii.nakryiko@xxxxxxxxx> wrote: > > > > On Thu, Jan 21, 2021 at 8:09 AM Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote: > > > > > > On Thu, Jan 21, 2021 at 2:38 PM Arnaldo Carvalho de Melo > > > <arnaldo.melo@xxxxxxxxx> wrote: > > > > > > > > Em Tue, Jan 12, 2021 at 04:27:59PM -0800, Tom Stellard escreveu: > > > > > On 1/12/21 10:40 AM, Jiri Olsa wrote: > > > > > > When processing kernel image build by clang we can > > > > > > find some functions without the name, which causes > > > > > > pahole to segfault. > > > > > > > > > > > > Adding extra checks to make sure we always have > > > > > > function's name defined before using it. > > > > > > > > > > > > > > > > I backported this patch to pahole 1.19, and I can confirm it fixes the > > > > > segfault for me. > > > > > > > > I'm applying v2 for this patch and based on your above statement I'm > > > > adding a: > > > > > > > > Tested-by: Tom Stellard <tstellar@xxxxxxxxxx> > > > > > > > > Ok? > > > > > > > > Who originally reported this? > > > > > > > > > > The origin was AFAICS the thread where I asked initially [1]. > > > > > > Tom reported in the same thread in [2] that pahole segfaults. > > > > > > Later in the thread Jiri offered a draft of this patch after doing some tests. > > > > > > I have tested all diffs and v1 and v2 of Jiri's patch. > > > ( Anyway, latest pahole ToT plus Jiri's patch did not solve my origin problem. ) > > > > Your original problem was with DWARF5 or DWARF4? I think you mentioned > > both at some point, but I remember I couldn't repro DWARF4 problems. > > If you still have problems, can you start a new thread with steps to > > repro (including Kconfig, tooling versions, etc). And one for each > > problem, no all at the same time, please. I honestly lost track of > > what's still not working among those multiple intertwined email > > threads, sorry about that. > > > > I love people saying "I have a (one) problem." :-). > > The origin was Debian kernel-team enabled BTF-debuginfo Kconfig. > > My main focus is to be as close to Debian's kernel-config and if this > works well with (experimental) Linux DWARF v5 support I am a happy > guy. I don't know what kernel config Debian is using, that's why I'm asking for kernel config that does cause the problem. Because the one I'm using doesn't. But this problem can be a result of a lot of things, specific compiler and its version, specific kernel config, who knows what else. > > Do you want Nick's DWARF v5 patch-series as a base? Arnaldo was going to figure out the DWARF v5 problem, so I'm leaving it up to him. I'm curious about DWARF v4 problems because no one yet reported that previously. > Thinking of DWARF-v4? > Use Nick's patchset or DWARF-v4 what is in Linux upstream means Linux > v5.11-rc4+? > What Git tree to use - Linus or one of your BPF/BTF folks? I checked both v5.11-rc4 and the latest bpf-next with CONFIG_DEBUG_INFO_DWARF4=y and CONFIG_DEBUG_INFO_BTF=y. I get no warnings, everything works. > > What version of pahole (latest Git) etc.? Latest pahole built from Git, yes. But let's not do it in a backwards manner with me telling you what works (my environment, my config), rather you telling us what *doesn't* work (your config, your environment), so that we can try to reproduce. > > - Sedat - > > > > > > > So up to you Arnaldo for the credits. > > > > > > - Sedat - > > > > > > [1] https://marc.info/?t=161036949500004&r=1&w=2 > > > [2] https://marc.info/?t=161036949500004&r=1&w=2 > > > > > > > - Arnaldo > > > > > > > > > -Tom > > > > > > > > > > > Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx> > > > > > > --- > > > > > > btf_encoder.c | 8 ++++++-- > > > > > > 1 file changed, 6 insertions(+), 2 deletions(-) > > > > > > > > > > > > diff --git a/btf_encoder.c b/btf_encoder.c > > > > > > index 333973054b61..17f7a14f2ef0 100644 > > > > > > --- a/btf_encoder.c > > > > > > +++ b/btf_encoder.c > > > > > > @@ -72,6 +72,8 @@ static int collect_function(struct btf_elf *btfe, GElf_Sym *sym) > > > > > > if (elf_sym__type(sym) != STT_FUNC) > > > > > > return 0; > > > > > > + if (!elf_sym__name(sym, btfe->symtab)) > > > > > > + return 0; > > > > > > if (functions_cnt == functions_alloc) { > > > > > > functions_alloc = max(1000, functions_alloc * 3 / 2); > > > > > > @@ -730,9 +732,11 @@ int cu__encode_btf(struct cu *cu, int verbose, bool force, > > > > > > if (!has_arg_names(cu, &fn->proto)) > > > > > > continue; > > > > > > if (functions_cnt) { > > > > > > - struct elf_function *func; > > > > > > + const char *name = function__name(fn, cu); > > > > > > + struct elf_function *func = NULL; > > > > > > - func = find_function(btfe, function__name(fn, cu)); > > > > > > + if (name) > > > > > > + func = find_function(btfe, name); > > > > > > if (!func || func->generated) > > > > > > continue; > > > > > > func->generated = true; > > > > > > > > > > > > > > > > > > > -- > > > > > > > > - Arnaldo
