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    SubjectRe: ERROR: INT DW_ATE_unsigned_1 Error emitting BTF type
    On Sat, Feb 6, 2021 at 10:48 AM Sedat Dilek <sedat.dilek@gmail.com> wrote:
    >
    > On Sat, Feb 6, 2021 at 10:32 AM Sedat Dilek <sedat.dilek@gmail.com> wrote:
    > >
    > > On Sat, Feb 6, 2021 at 9:32 AM Sedat Dilek <sedat.dilek@gmail.com> wrote:
    > > >
    > > > On Sat, Feb 6, 2021 at 9:27 AM Yonghong Song <yhs@fb.com> wrote:
    > > > >
    > > > >
    > > > >
    > > > > On 2/5/21 10:52 PM, Sedat Dilek wrote:
    > > > > > On Sat, Feb 6, 2021 at 7:26 AM Sedat Dilek <sedat.dilek@gmail.com> wrote:
    > > > > >>
    > > > > >> On Sat, Feb 6, 2021 at 6:53 AM Sedat Dilek <sedat.dilek@gmail.com> wrote:
    > > > > >>>
    > > > > >>> On Sat, Feb 6, 2021 at 6:44 AM Sedat Dilek <sedat.dilek@gmail.com> wrote:
    > > > > >>>>
    > > > > >>>> On Sat, Feb 6, 2021 at 4:34 AM Sedat Dilek <sedat.dilek@gmail.com> wrote:
    > > > > >>>>>
    > > > > >>>>> On Fri, Feb 5, 2021 at 10:54 PM Yonghong Song <yhs@fb.com> wrote:
    > > > > >>>>>>
    > > > > >>>>>>
    > > > > >>>>>>
    > > > > >>>>>> On 2/5/21 12:31 PM, Sedat Dilek wrote:
    > > > > >>>>>>> On Fri, Feb 5, 2021 at 9:03 PM Yonghong Song <yhs@fb.com> wrote:
    > > > > >>>>>>>>
    > > > > >>>>>>>>
    > > > > >>>>>>>>
    > > > > >>>>>>>> On 2/5/21 11:24 AM, Arnaldo Carvalho de Melo wrote:
    > > > > >>>>>>>>> Em Fri, Feb 05, 2021 at 11:10:08AM -0800, Yonghong Song escreveu:
    > > > > >>>>>>>>>> On 2/5/21 11:06 AM, Sedat Dilek wrote:
    > > > > >>>>>>>>>>> On Fri, Feb 5, 2021 at 7:53 PM Sedat Dilek <sedat.dilek@gmail.com> wrote:
    > > > > >>>>>>>>>>> Grepping through linux.git/tools I guess some BTF tools/libs need to
    > > > > >>>>>>>>>>> know what BTF_INT_UNSIGNED is?
    > > > > >>>>>>>>>
    > > > > >>>>>>>>>> BTF_INT_UNSIGNED needs kernel support. Maybe to teach pahole to
    > > > > >>>>>>>>>> ignore this for now until kernel infrastructure is ready.
    > > > > >>>>>>>>>
    > > > > >>>>>>>>> Yeah, I thought about doing that.
    > > > > >>>>>>>>>
    > > > > >>>>>>>>>> Not sure whether this information will be useful or not
    > > > > >>>>>>>>>> for BTF. This needs to be discussed separately.
    > > > > >>>>>>>>>
    > > > > >>>>>>>>> Maybe search for the rationale for its introduction in DWARF.
    > > > > >>>>>>>>
    > > > > >>>>>>>> In LLVM, we have:
    > > > > >>>>>>>> uint8_t BTFEncoding;
    > > > > >>>>>>>> switch (Encoding) {
    > > > > >>>>>>>> case dwarf::DW_ATE_boolean:
    > > > > >>>>>>>> BTFEncoding = BTF::INT_BOOL;
    > > > > >>>>>>>> break;
    > > > > >>>>>>>> case dwarf::DW_ATE_signed:
    > > > > >>>>>>>> case dwarf::DW_ATE_signed_char:
    > > > > >>>>>>>> BTFEncoding = BTF::INT_SIGNED;
    > > > > >>>>>>>> break;
    > > > > >>>>>>>> case dwarf::DW_ATE_unsigned:
    > > > > >>>>>>>> case dwarf::DW_ATE_unsigned_char:
    > > > > >>>>>>>> BTFEncoding = 0;
    > > > > >>>>>>>> break;
    > > > > >>>>>>>>
    > > > > >>>>>>>> I think DW_ATE_unsigned can be ignored in pahole since
    > > > > >>>>>>>> the default encoding = 0. A simple comment is enough.
    > > > > >>>>>>>>
    > > > > >>>>>>>
    > > > > >>>>>>> Yonghong Son, do you have a patch/diff for me?
    > > > > >>>>>>
    > > > > >>>>>> Looking at error message from log:
    > > > > >>>>>>
    > > > > >>>>>> LLVM_OBJCOPY=/opt/binutils/bin/objcopy /opt/pahole/bin/pahole -J
    > > > > >>>>>> .tmp_vmlinux.btf
    > > > > >>>>>> [115] INT DW_ATE_unsigned_1 Error emitting BTF type
    > > > > >>>>>> Encountered error while encoding BTF.
    > > > > >>>>>>
    > > > > >>>>>> Not exactly what is the root cause. Maybe bt->bit_size is not
    > > > > >>>>>> encoded correctly. Could you put vmlinux (in the above it is
    > > > > >>>>>> .tmp_vmlinux.btf) somewhere, I or somebody else can investigate
    > > > > >>>>>> and provide a proper fix.
    > > > > >>>>>>
    > > > > >>>>>
    > > > > >>>>> [ TO: Masahiro ]
    > > > > >>>>>
    > > > > >>>>> Thanks for taking care Yonghong - hope this is your first name, if not
    > > > > >>>>> I am sorry.
    > > > > >>>>> In case of mixing my first and last name you will make me female -
    > > > > >>>>> Dilek is a Turkish female first name :-).
    > > > > >>>>> So, in some cultures you need to be careful.
    > > > > >>>>>
    > > > > >>>>> Anyway... back to business and facts.
    > > > > >>>>>
    > > > > >>>>> Out of frustration I killed my last build via `make distclean`.
    > > > > >>>>> The whole day I tested diverse combination of GCC-10 and LLVM-12
    > > > > >>>>> together with BTF Kconfigs, selfmade pahole, etc.
    > > > > >>>>>
    > > > > >>>>> I will do ne run with some little changes:
    > > > > >>>>>
    > > > > >>>>> #1: Pass LLVM_IAS=1 to make (means use Clang's Integrated ASsembler -
    > > > > >>>>> as per Nick this leads to the same error - should be unrelated)
    > > > > >>>>> #2: I did: DEBUG_INFO_COMPRESSED y -> n
    > > > > >>>>>
    > > > > >>>>> #2 I did in case you need vmlinux and I have to upload - I will
    > > > > >>>>> compress the resulting vmlinux with ZSTD.
    > > > > >>>>> You need vmlinux or .tmp_vmlinux.btf file?
    > > > > >>>>> Nick was not allowed from his company to download from a Dropbox link.
    > > > > >>>>> So, as an alternative I can offer GoogleDrive...
    > > > > >>>>> ...or bomb into your INBOX :-).
    > > > > >>>>>
    > > > > >>>>> Now, why I CCed Masahiro:
    > > > > >>>>>
    > > > > >>>>> In case of ERRORs when running `scripts/link-vmlinux.sh` above files
    > > > > >>>>> will be removed.
    > > > > >>>>>
    > > > > >>>>> Last, I found a hack to bypass this - means to keep these files (I
    > > > > >>>>> need to check old emails).
    > > > > >>>>>
    > > > > >>>>> Masahiro, you see a possibility to have a way to keep these files in
    > > > > >>>>> case of ERRORs without doing hackery?
    > > > > >>>>>
    > > > > >>>>> From a previous post in this thread:
    > > > > >>>>>
    > > > > >>>>> + info BTF .btf.vmlinux.bin.o
    > > > > >>>>> + [ != silent_ ]
    > > > > >>>>> + printf %-7s %s\n BTF .btf.vmlinux.bin.o
    > > > > >>>>> BTF .btf.vmlinux.bin.o
    > > > > >>>>> + LLVM_OBJCOPY=llvm-objcopy /opt/pahole/bin/pahole -J .tmp_vmlinux.btf
    > > > > >>>>> [2] INT long unsigned int Error emitting BTF type
    > > > > >>>>> Encountered error while encoding BTF.
    > > > > >>>>> + llvm-objcopy --only-section=.BTF --set-section-flags
    > > > > >>>>> .BTF=alloc,readonly --strip-all .tmp_vmlinux.btf .btf.vmlinux.bin.o
    > > > > >>>>> ...
    > > > > >>>>> + info BTFIDS vmlinux
    > > > > >>>>> + [ != silent_ ]
    > > > > >>>>> + printf %-7s %s\n BTFIDS vmlinux
    > > > > >>>>> BTFIDS vmlinux
    > > > > >>>>> + ./tools/bpf/resolve_btfids/resolve_btfids vmlinux
    > > > > >>>>> FAILED: load BTF from vmlinux: Invalid argument
    > > > > >>>>> + on_exit
    > > > > >>>>> + [ 255 -ne 0 ]
    > > > > >>>>> + cleanup
    > > > > >>>>> + rm -f .btf.vmlinux.bin.o
    > > > > >>>>> + rm -f .tmp_System.map
    > > > > >>>>> + rm -f .tmp_vmlinux.btf .tmp_vmlinux.kallsyms1
    > > > > >>>>> .tmp_vmlinux.kallsyms1.S .tmp_vmlinux.kallsyms1.o
    > > > > >>>>> .tmp_vmlinux.kallsyms2 .tmp_vmlinux.kallsyms2.S .tmp_vmlinux.kallsyms
    > > > > >>>>> 2.o
    > > > > >>>>> + rm -f System.map
    > > > > >>>>> + rm -f vmlinux
    > > > > >>>>> + rm -f vmlinux.o
    > > > > >>>>> make[3]: *** [Makefile:1166: vmlinux] Error 255
    > > > > >>>>>
    > > > > >>>>> ^^^ Look here.
    > > > > >>>>>
    > > > > >>>>
    > > > > >>>> With this diff:
    > > > > >>>>
    > > > > >>>> $ git diff scripts/link-vmlinux.sh
    > > > > >>>> diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
    > > > > >>>> index eef40fa9485d..40f1b6aae553 100755
    > > > > >>>> --- a/scripts/link-vmlinux.sh
    > > > > >>>> +++ b/scripts/link-vmlinux.sh
    > > > > >>>> @@ -330,7 +330,7 @@ vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o}
    > > > > >>>> # fill in BTF IDs
    > > > > >>>> if [ -n "${CONFIG_DEBUG_INFO_BTF}" -a -n "${CONFIG_BPF}" ]; then
    > > > > >>>> info BTFIDS vmlinux
    > > > > >>>> - ${RESOLVE_BTFIDS} vmlinux
    > > > > >>>> + ##${RESOLVE_BTFIDS} vmlinux
    > > > > >>>> fi
    > > > > >>>>
    > > > > >>>> if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then
    > > > > >>>>
    > > > > >>>> This files are kept - not removed:
    > > > > >>>>
    > > > > >>>> $ LC_ALL=C ll .*btf* vmlinux vmlinux.o
    > > > > >>>> -rwxr-xr-x 1 dileks dileks 31M Feb 6 06:37 .btf.vmlinux.bin.o
    > > > > >>>> -rwxr-xr-x 1 dileks dileks 348M Feb 6 06:37 .tmp_vmlinux.btf
    > > > > >>>> -rwxr-xr-x 1 dileks dileks 348M Feb 6 06:37 vmlinux
    > > > > >>>> -rw-r--r-- 1 dileks dileks 344M Feb 6 06:37 vmlinux.o
    > > > > >>>>
    > > > > >>>> Pleas let me know where to upload - Dropbox or GoogleDrive or
    > > > > >>>> elsewhere and give me a link.
    > > > > >>>>
    > > > > >>>
    > > > > >>>
    > > > > >>> WOW, ZSTD is great :-).
    > > > > >>>
    > > > > >>> $ zstd -19 -T0 -v vmlinux
    > > > > >>> *** zstd command line interface 64-bits v1.4.8, by Yann Collet ***
    > > > > >>> Note: 2 physical core(s) detected
    > > > > >>> vmlinux : 22.71% (364466016 => 82784801 bytes, vmlinux.zst)
    > > > > >>>
    > > > > >>> $ du -m vmlinux*
    > > > > >>> 348 vmlinux
    > > > > >>> 79 vmlinux.zst
    > > > > >>>
    > > > > >>
    > > > > >> Dropbox link:
    > > > > >> https://www.dropbox.com/sh/kvyh8ps7na0r1h5/AABfyNfDZ2bESse_bo4h05fFa?dl=0
    > > > > >>
    > > > > >> I hope this is public available.
    > > > > >>
    > > > > >
    > > > > > Inspecting vmlinux with llvm-dwarf:
    > > > > >
    > > > > > $ /opt/llvm-toolchain/bin/llvm-dwarfdump vmlinux | grep DW_AT_name |
    > > > > > grep DW_ATE_ | sort | uniq
    > > > > > DW_AT_name ("DW_ATE_signed_1")
    > > > > > DW_AT_name ("DW_ATE_signed_16")
    > > > > > DW_AT_name ("DW_ATE_signed_32")
    > > > > > DW_AT_name ("DW_ATE_signed_64")
    > > > > > DW_AT_name ("DW_ATE_signed_8")
    > > > > > DW_AT_name ("DW_ATE_unsigned_1")
    > > > > > DW_AT_name ("DW_ATE_unsigned_128")
    > > > > > DW_AT_name ("DW_ATE_unsigned_16")
    > > > > > DW_AT_name ("DW_ATE_unsigned_24")
    > > > > > DW_AT_name ("DW_ATE_unsigned_32")
    > > > > > DW_AT_name ("DW_ATE_unsigned_40")
    > > > > > DW_AT_name ("DW_ATE_unsigned_64")
    > > > > > DW_AT_name ("DW_ATE_unsigned_8")
    > > > > >
    > > > > > - Sedat -
    > > > >
    > > > > Thanks for the above dropbot link, I am able to reproduce the issue.
    > > > >
    > > > > I tried to use latest llvm + Nick's patch + latest pahole + dwarf5
    > > > > config option to compile kernel with LLVM=1 LLVM_IAS=1, somehow
    > > > > I did not hit the issue. It complained like
    > > > >
    > > > > MODPOST vmlinux.symvers
    > > > > WARNING: modpost: vmlinux.o(.text+0x6ce73): Section mismatch in
    > > > > reference from the function __nodes
    > > > > _weight() to the variable .init.data:numa_nodes_parsed
    > > > > The function __nodes_weight() references
    > > > > the variable __initdata numa_nodes_parsed.
    > > > > This is often because __nodes_weight lacks a __initdata
    > > > > annotation or the annotation of numa_nodes_parsed is wrong.
    > > > >
    > > > > but otherwise compilation is fine.
    > > > >
    > > > > With the above vmlinux, the issue appears to be handling
    > > > > DW_ATE_signed_1, DW_ATE_unsigned_{1,24,40}.
    > > > >
    > > > > The following patch should fix the issue:
    > > > >
    > > > > -bash-4.4$ git diff
    > > > >
    > > > > diff --git a/dwarf_loader.c b/dwarf_loader.c
    > > > >
    > > > > index b73d786..0341b5e 100644
    > > > >
    > > > > --- a/dwarf_loader.c
    > > > >
    > > > > +++ b/dwarf_loader.c
    > > > >
    > > > > @@ -467,8 +467,16 @@ static struct base_type *base_type__new(Dwarf_Die
    > > > > *die, struct cu *cu)
    > > > >
    > > > >
    > > > > if (bt != NULL) {
    > > > >
    > > > > tag__init(&bt->tag, cu, die);
    > > > >
    > > > > - bt->name = strings__add(strings, attr_string(die,
    > > > > DW_AT_name));
    > > > > - bt->bit_size = attr_numeric(die, DW_AT_byte_size) * 8;
    > > > >
    > > > > + const char *name = attr_string(die, DW_AT_name);
    > > > >
    > > > > + bt->name = strings__add(strings, name);
    > > > >
    > > > > + /* DW_ATE_unsigned_1 has DW_AT_byte_size == 0.
    > > > >
    > > > > + * specially process it.
    > > > >
    > > > > + */
    > > > >
    > > > > + if (strcmp(name, "DW_ATE_unsigned_1") == 0)
    > > > >
    > > > > + bt->bit_size = 1;
    > > > >
    > > > > + else
    > > > >
    > > > > + bt->bit_size = attr_numeric(die,
    > > > > DW_AT_byte_size) * 8;
    > > > > +
    > > > >
    > > > > uint64_t encoding = attr_numeric(die, DW_AT_encoding);
    > > > > bt->is_bool = encoding == DW_ATE_boolean;
    > > > > bt->is_signed = encoding == DW_ATE_signed;
    > > > > diff --git a/libbtf.c b/libbtf.c
    > > > > index 9f76283..b5aa077 100644
    > > > > --- a/libbtf.c
    > > > > +++ b/libbtf.c
    > > > > @@ -367,13 +367,32 @@ static void btf_log_func_param(const struct
    > > > > btf_elf *btfe,
    > > > > }
    > > > > }
    > > > >
    > > > > +/* btf requires power-of-2 bytes, yet dwarf may have something like
    > > > > + * DW_ATE_unsigned_24 which encodes as 24 bits (3 bytes).
    > > > > + */
    > > > > +static int bits_to_int_bytes(uint16_t bit_size)
    > > > > +{
    > > > > + if (bit_size <= 8)
    > > > > + return 1;
    > > > > + if (bit_size <= 16)
    > > > > + return 2;
    > > > > + if (bit_size <= 32)
    > > > > + return 4;
    > > > > + if (bit_size <= 64)
    > > > >
    > > > > + return 8;
    > > > >
    > > > > + if (bit_size <= 128)
    > > > > + return 16;
    > > > > + /* BTF supports upto 16byte int (__int128). */
    > > > > + return -1;
    > > > > +}
    > > > > +
    > > > > int32_t btf_elf__add_base_type(struct btf_elf *btfe, const struct
    > > > > base_type *bt,
    > > > > const char *name)
    > > > > {
    > > > > struct btf *btf = btfe->btf;
    > > > > const struct btf_type *t;
    > > > > uint8_t encoding = 0;
    > > > > - int32_t id;
    > > > > + int32_t id, nbytes;
    > > > >
    > > > > if (bt->is_signed) {
    > > > > encoding = BTF_INT_SIGNED;
    > > > > @@ -384,7 +403,13 @@ int32_t btf_elf__add_base_type(struct btf_elf
    > > > > *btfe, const struct base_type *b
    > > > > t,
    > > > > return -1;
    > > > > }
    > > > > - id = btf__add_int(btf, name, BITS_ROUNDUP_BYTES(bt->bit_size),
    > > > > encoding);
    > > > > + nbytes = bits_to_int_bytes(bt->bit_size);
    > > > > + if (nbytes < 0) {
    > > > > + fprintf(stderr, "not supported bit_size %hu\n",
    > > > > bt->bit_size);
    > > > > + return -1;
    > > > > + }
    > > > > +
    > > > > + id = btf__add_int(btf, name, nbytes, encoding);
    > > > > if (id < 0) {
    > > > > btf_elf__log_err(btfe, BTF_KIND_INT, name, true, "Error
    > > > > emitting BTF type");
    > > > > } else {
    > > > > -bash-4.4$
    > > > >
    > > > > Please help do a test. I can submit a formal patch tomorrow.
    > > >
    > > > Thanks for the patch.
    > > >
    > > > Can you attach the diff as Gmail has totally truncated/malformed it?
    > > >
    > > > For the Linux breakage - you will need some additional Clang specific patches.
    > > > Is this Linux 5.11-rcX?
    > > > The "Blocking bugs" are listed in the first post of "Linux 5.11 release cycle".
    > > > Hope this helps.
    > > >
    > > > This is cool co-working :-).
    > > >
    > > > - Sedat -
    > > >
    > > > [1] https://github.com/ClangBuiltLinux/linux/issues/1228
    > >
    > > With the attached diff and new selfmade pahole looks good here.
    > >
    > > Passed (see line-numbers):
    > >
    > > 11090:+ info LD .tmp_vmlinux.btf
    > > 11099:+ info BTF .btf.vmlinux.bin.o
    > > 11103:+ LLVM_OBJCOPY=llvm-objcopy /opt/pahole/bin/pahole -J .tmp_vmlinux.btf
    > > 11121:+ info LD .tmp_vmlinux.kallsyms1
    > > 11139:+ info KSYMS .tmp_vmlinux.kallsyms1.S
    > > 11145:+ info AS .tmp_vmlinux.kallsyms1.S
    > > 11160:+ info LD .tmp_vmlinux.kallsyms2
    > > 11178:+ info KSYMS .tmp_vmlinux.kallsyms2.S
    > > 11184:+ info AS .tmp_vmlinux.kallsyms2.S
    > > 11200:+ info LD vmlinux
    > > 11210:+ info BTFIDS vmlinux
    > > 11216:+ info SORTTAB vmlinux
    > >
    > > Still building linux-kernel...
    > >
    > > Will report later if I was able to boot on bare metal.
    > >
    >
    > When running scripts/Makefile.modfinal:
    >
    > ...
    > not supported bit_size 160
    > Encountered error while encoding BTF.
    > ...
    > make[5]: *** [scripts/Makefile.modfinal:59:
    > drivers/net/ethernet/mellanox/mlx5/core/mlx5_core.ko] Error 1
    > make[5]: *** Deleting file
    > 'drivers/net/ethernet/mellanox/mlx5/core/mlx5_core.ko'
    >

    I added "bit_size 160" to libbtf.c:

    static int bits_to_int_bytes(uint16_t bit_size)
    {
    if (bit_size <= 8)
    return 1;
    if (bit_size <= 16)
    return 2;
    if (bit_size <= 32)
    return 4;
    if (bit_size <= 64)
    return 8;
    if (bit_size <= 128)
    return 16;
    if (bit_size <= 160)
    return 20;
    /* BTF supports upto 16byte int (__int128). */
    return -1;
    }

    It still breaks with:

    [521367] INT DW_ATE_unsigned_160 Error emitting BTF type
    Encountered error while encoding BTF.
    make[5]: *** [scripts/Makefile.modfinal:58:
    drivers/net/ethernet/mellanox/mlx5/core/mlx5_core.ko] Error 1
    make[5]: *** Deleting file
    'drivers/net/ethernet/mellanox/mlx5/core/mlx5_core.ko'

    Comments?

    - Sedat -

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