Objdump can't parse our Linux debug information

laanwj commented at 8:37 pm on May 1, 2024: member

Upstream issue: https://sourceware.org/bugzilla/show_bug.cgi?id=31692

The debug information in the shipped .dbg artifacts seems to be unusable for objdump. The .debug_info section is corrupt:

0$ tar -zxvf bitcoin-27.0-x86_64-linux-gnu-debug.tar.gz
1$ objdump -Wi bitcoin-27.0/bin/bitcoin-cli.dbg
2
3Section '.debug_info' has an invalid size: 0.
4
5bitcoin-27.0/bin/bitcoin-cli.dbg:     file format elf64-x86-64
6
7Section '.debug_info' has an invalid size: 0.

i’ve checked various Linux architectures (at least x86_64, ARM, RISC-V) and the same issue exists there. Interestingly, the Windows build is unaffected. Maybe because of a different gcc/binutils? Builds outside guix seem unaffected.

My first thought is that something goes wrong while splitting the debug symbols. However, the unsplitted binaries suffer from the same problem:

0$ objdump -Wi guix-build-27.0/distsrc-27.0-x86_64-linux-gnu/src/bitcoind
1
2Section '.debug_info' has an invalid size: 0

This issue affects at least release 27.0 and current master.

Edit: Looks like there is a .debug_info section in the files. objdump -s -j .debug_info bitcoin-27.0/bin/bitcoind.dbg shows contents, so it’s not really size 0. But it can’t be parsed somehow.

laanwj added the label Build system on May 1, 2024

laanwj assigned laanwj on May 1, 2024

laanwj commented at 9:23 pm on May 1, 2024: member

Okay, may be a objdump bug actually?

readelf -wi (which should be equivalent to objdump -Wi) parses the same section fine. So does gdb it seems?

(FWIW i did try various versions of objdump before reporting this)

laanwj commented at 9:24 pm on May 1, 2024: member

Closing for now.

edit: It’s this objdump bug in dealing with compressed debug info sections: https://sourceware.org/bugzilla/show_bug.cgi?id=24319 which was supposedly fixed but… sigh

laanwj closed this on May 1, 2024

laanwj renamed this:
~~Linux debug information for release is broken~~
Objdump can't parse our Linux debug information
on May 2, 2024

laanwj added the label Upstream on May 2, 2024

laanwj commented at 6:04 am on May 2, 2024: member

Reopening with more accurate title (phew).

Filed upstream issue: https://sourceware.org/bugzilla/show_bug.cgi?id=31692

laanwj reopened this on May 2, 2024

fanquake commented at 7:42 am on May 2, 2024: member

Interestingly, the Windows build is unaffected. Maybe because of a different gcc/binutils?

This is probably because the Windows Binutils is configured without support for compressed debug sections, as it was, iirc, causing other windows build issues.

laanwj commented at 7:47 am on May 2, 2024: member

This is probably because the Windows Binutils is configured without support for compressed debug sections, as it was, iirc, causing other windows build issues.

Right, that makes sense. DWARF in PE binaires is a quite peculiar concept in the first place–heck, GNU even has its own way to encode the long section names needed: lief-project/LIEF#1043. i’m not surprised it’s not set up to handle compressed sections.

laanwj commented at 12:24 pm on May 2, 2024: member

This was already solved upstream!

Diff: https://sourceware.org/git/?p=binutils-gdb.git;a=blobdiff;f=binutils/objdump.c;h=3d70df470f290f7e4dc46cf80bc075f3015e6c14;hp=5acaa54929dbd4bbe37d7a2195ca698bfca603d0;hb=635d05b88f4823f46ef1ddbb3d438db16c0f6e71;hpb=5ce0e02478cc79a260c7e29822450284a32b9b12

i expect this will land in binutils 2.43. No need to keep this issue open.

laanwj closed this on May 2, 2024

Objdump can’t parse our Linux debug information #30016