On Tue, Aug 20, 2024 at 10:59:50AM +0200, Jiri Slaby (SUSE) wrote: > From: Jiri Slaby <jslaby@xxxxxxx> > > == WARNING == > This is only a PoC. There are deficiencies like CROSS_COMPILE or LLVM > are completely unhandled. > > The simple version is just do there: > ifeq ($(CONFIG_64BIT,y) > but it has its own deficiencies, of course. > > So any ideas, inputs? > == WARNING == > > When pahole is run with -j on 32bit userspace (32bit pahole in > particular), it randomly fails with OOM: > > btf_encoder__tag_kfuncs: Failed to get ELF section(62) data: out of memory. > > btf_encoder__encode: failed to tag kfuncs! > > or simply SIGSEGV (failed to allocate the btf encoder). > > It very depends on how many threads are created. > > So do not invoke pahole with -j on 32bit. could you share more details about your setup? does it need to run on pure 32bit to reproduce? I can't reproduce when doing cross build and running 32 bit pahole on x86_64.. I do see some errors though [667939] STRUCT bpf_prog_aux Error emitting BTF type Encountered error while encoding BTF. thanks, jirka > > Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> > Fixes: b4f72786429c ("scripts/pahole-flags.sh: Parse DWARF and generate BTF with multithreading.") > Closes: https://bugzilla.suse.com/show_bug.cgi?id=1229450 > Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx> > Cc: Nathan Chancellor <nathan@xxxxxxxxxx> > Cc: Nicolas Schier <nicolas@xxxxxxxxx> > Cc: Alexei Starovoitov <ast@xxxxxxxxxx> > Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx> > Cc: Andrii Nakryiko <andrii@xxxxxxxxxx> > Cc: Martin KaFai Lau <martin.lau@xxxxxxxxx> > Cc: Eduard Zingerman <eddyz87@xxxxxxxxx> > Cc: Song Liu <song@xxxxxxxxxx> > Cc: Yonghong Song <yonghong.song@xxxxxxxxx> > Cc: John Fastabend <john.fastabend@xxxxxxxxx> > Cc: KP Singh <kpsingh@xxxxxxxxxx> > Cc: Stanislav Fomichev <sdf@xxxxxxxxxxx> > Cc: Hao Luo <haoluo@xxxxxxxxxx> > Cc: Jiri Olsa <jolsa@xxxxxxxxxx> > Cc: linux-kernel@xxxxxxxxxxxxxxx > Cc: linux-kbuild@xxxxxxxxxxxxxxx > Cc: bpf@xxxxxxxxxxxxxxx > Cc: shung-hsi.yu@xxxxxxxx > Cc: msuchanek@xxxxxxxx > --- > init/Kconfig | 4 ++++ > scripts/Makefile.btf | 2 ++ > scripts/pahole-class.sh | 21 +++++++++++++++++++++ > 3 files changed, 27 insertions(+) > create mode 100644 scripts/pahole-class.sh > > diff --git a/init/Kconfig b/init/Kconfig > index f36ca8a0e209..f5e80497eef0 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -113,6 +113,10 @@ config PAHOLE_VERSION > int > default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE)) > > +config PAHOLE_CLASS > + string > + default $(shell,$(srctree)/scripts/pahole-class.sh $(PAHOLE)) > + > config CONSTRUCTORS > bool > > diff --git a/scripts/Makefile.btf b/scripts/Makefile.btf > index b75f09f3f424..f7de8e922bce 100644 > --- a/scripts/Makefile.btf > +++ b/scripts/Makefile.btf > @@ -12,7 +12,9 @@ endif > > pahole-flags-$(call test-ge, $(pahole-ver), 121) += --btf_gen_floats > > +ifeq ($(CONFIG_PAHOLE_CLASS),ELF64) > pahole-flags-$(call test-ge, $(pahole-ver), 122) += -j > +endif > > pahole-flags-$(call test-ge, $(pahole-ver), 125) += --skip_encoding_btf_inconsistent_proto --btf_gen_optimized > > diff --git a/scripts/pahole-class.sh b/scripts/pahole-class.sh > new file mode 100644 > index 000000000000..d15a92077f76 > --- /dev/null > +++ b/scripts/pahole-class.sh > @@ -0,0 +1,21 @@ > +#!/bin/sh > +# SPDX-License-Identifier: GPL-2.0 > +# > +# Usage: $ ./pahole-class.sh pahole > +# > +# Prints pahole's ELF class, such as ELF64 > + > +if [ ! -x "$(command -v "$@")" ]; then > + echo 0 > + exit 1 > +fi > + > +PAHOLE="$(which "$@")" > +CLASS="$(readelf -h "$PAHOLE" 2>/dev/null | sed -n 's/.*Class: *// p')" > + > +# Scripts like scripts/dummy-tools/pahole > +if [ -n "$CLASS" ]; then > + echo "$CLASS" > +else > + echo ELF64 > +fi > -- > 2.46.0 >