missing debug symbol for 3.0a-2ubuntu0.4

[胡玮文]

The debug symbol for tmux package is only available for 3.0a-2, but not for the latest 3.0a-2ubuntu0.4 in focal. Making it nearly impossible to debug the segfault we have seen.

$ apt policy tmux-dbgsym
tmux-dbgsym:
  Installed: (none)
  Candidate: 3.0a-2
  Version table:
     3.0a-2 500
        500 http://ddebs.ubuntu.com focal/main amd64 Packages
$ apt policy tmux
tmux:
  Installed: 3.0a-2ubuntu0.4
  Candidate: 3.0a-2ubuntu0.4
  Version table:
 *** 3.0a-2ubuntu0.4 500
        500 https://mirrors.scut-smil.cn/ubuntu focal-updates/main amd64 Packages
        500 https://mirrors.scut-smil.cn/ubuntu focal-security/main amd64 Packages
        100 /var/lib/dpkg/status
     3.0a-2 500
        500 https://mirrors.scut-smil.cn/ubuntu focal/main amd64 Packages

I think this issue is not limited to tmux. even apt don't get an updated ddeb package at http://ddebs.ubuntu.com/dists/focal-updates/main/binary-amd64/Packages

[Athos Ribeiro (athos-ribeiro)]

Hi,

Thanks for reporting this one.

browsing to https://launchpad.net/ubuntu/+source/tmux, I can see that the debug symbols package was indeed built, but was not published.

For instance, for amd64, you could fetch it from https://launchpad.net/ubuntu/+archive/primary/+files/tmux-dbgsym_3.0a-2ubuntu0.4_amd64.ddeb.

For this specific case, I will ping the archive admins to check wahat is going on here (but hopefully you won't be blocked on this since you can fetch the package from launchpad directly).

[Sergio Durigan Junior (sergiodj)]

Hey!

Kudos to Athos for bringing this to my attention. Thanks!

I confirmed here that our debuginfod instance (https://debuginfod.ubuntu.com) does carry the debuginfo in question:

$ DEBUGINFOD_URLS=https://debuginfod.ubuntu.com debuginfod-find debuginfo 0d8c82958f52b0ab83205cbf4e03f125f3ecb0ec
/home/ubuntu/.cache/debuginfod_client/0d8c82958f52b0ab83205cbf4e03f125f3ecb0ec/debuginfo

Unfortunately, the GDB we ship in Focal doesn't support debuginfod. For that reason, I built a newer GDB here:

https://launchpad.net/~sergiodj/+archive/ubuntu/gdb-12-focal-backport

If you're comfortable installing from a PPA, feel free to use it and let me know if you run into problems. All you need to do after installing this newer GDB is to export DEBUGINFOD_URLS=https://debuginfod.ubuntu.com.

Cheers.

[Athos Ribeiro (athos-ribeiro)]

Since the dbg symbols package was indeed built and we already set ddeb-retriever to track the missing package in the archive down, I am marking the tmux bugas invalid here.