Re: Bug#1076564: pahole BTF processing seems flaky on powerpc

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Adding Alan and Jiri to the CC list.

On Fri, Jul 19, 2024 at 08:53:24AM +0200, Domenico Andreoli wrote:
> Hi Arnaldo,
> 
> On Thu, Jul 18, 2024 at 11:56:09PM +0200, Ben Hutchings wrote:
> > Package: pahole
> > Version: 1.27-1
> > Severity: normal
> > X-Debbugs-Cc: debian-kernel@lists.debian.org
> > 
> > Several kernel builds on powerpc have failed recently:
> > 
> > 6.8.12-1:    https://buildd.debian.org/status/fetch.php?pkg=linux&arch=powerpc&ver=6.8.12-1&stamp=1717234422&raw=1
> > 6.9.9-1:     https://buildd.debian.org/status/fetch.php?pkg=linux&arch=powerpc&ver=6.9.9-1&stamp=1720906547&raw=1
> > 6.10-1~exp1: https://buildd.debian.org/status/fetch.php?pkg=linux&arch=powerpc&ver=6.10-1%7Eexp1&stamp=1721287862&raw=1
> > 
> > Note, these log files are up to 270 MB in size and should be
> > downloaded; at least Firefox becomes unresponsive when trying to
> > display them.
> > 
> > For each of these, the failure seems to start with an error from
> > pahole such as:
> > 
> >     [102044] ARRAY (anon) type_id=99491 index_type_id=14 nr_elems=12 Error emitting BTF type
> >     Encountered error while encoding BTF.
> 
> Does the above error ring any bell?

Nope
 
> Is there anything I can do to help?

From the 6.10-1~exp1:
https://buildd.debian.org/status/fetch.php?pkg=linux&arch=powerpc&ver=6.10-1%7Eexp1&stamp=1721287862&raw=1
file:

+ LLVM_OBJCOPY=powerpc-linux-gnu-objcopy pahole -J -j --btf_features=encode_force,var,float,enum64,decl_tag,type_tag,optimized_func,consistent_func --lang_exclude=rust .tmp_vmlinux.btf

Can I have access to that .tmp_vmlinux.btf file so that I can try to
reproduce it here?

- Arnaldo
 
> > 
> > This does *not* happen consistently.  Compare these successful
> > builds:
> > 
> > 6.8.12-1:    https://buildd.debian.org/status/fetch.php?pkg=linux&arch=powerpc&ver=6.8.12-1&stamp=1717278092&raw=1
> > - This same version failed to build on the first try.
> > 6.9.7-1:     https://buildd.debian.org/status/fetch.php?pkg=linux&arch=powerpc&ver=6.9.7-1&stamp=1719538806&raw=1
> > - Earlier and later 6.9.x versions failed to build.
> > 
> > Both pahole versions 1.26-1 and 1.27-1 have been used in both
> > successful and failing builds.
> > 
> > Ben.
> > 
> > -- System Information:
> > Debian Release: trixie/sid
> >   APT prefers unstable-debug
> >   APT policy: (500, 'unstable-debug'), (500, 'stable-updates'), (500, 'stable-security'), (500, 'oldstable-updates'), (500, 'oldstable-security'), (500, 'oldoldstable-updates'), (500, 'oldoldstable'), (500, 'unstable'), (500, 'stable'), (500, 'oldstable'), (1, 'experimental')
> > Architecture: amd64 (x86_64)
> > Foreign Architectures: i386
> > 
> > Kernel: Linux 6.9.9-amd64 (SMP w/12 CPU threads; PREEMPT)
> > Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE not set
> > Shell: /bin/sh linked to /usr/bin/dash
> > Init: systemd (via /run/systemd/system)
> > LSM: AppArmor: enabled
> > 
> > Versions of packages pahole depends on:
> > ii  libbpf1     1:1.4.3-1
> > ii  libc6       2.39-4
> > ii  libdw1t64   0.191-2
> > ii  libelf1t64  0.191-2
> > ii  zlib1g      1:1.3.dfsg+really1.3.1-1
> > 
> > pahole recommends no packages.
> > 
> > pahole suggests no packages.
> > 
> > -- debconf-show failed
> 
> -- 
> rsa4096: 3B10 0CA1 8674 ACBA B4FE  FCD2 CE5B CF17 9960 DE13
> ed25519: FFB4 0CC3 7F2E 091D F7DA  356E CC79 2832 ED38 CB05