Control: tags -1 + moreinfo upstream

Hi

On Wed, Mar 11, 2026 at 11:02:42AM +0100, Alejandro Olivan Alvarez wrote:
> Package: linux-image-6.12.73+deb13-amd64
> Version: 6.12.73-1
> Severity: normal
> X-Debbugs-Cc: [email protected]
> 
> Dear Maintainer,
> 
>    * What led up to the situation?
>         apt-get dist-upgrade
> 
>    * What exactly did you do (or not do) that was effective (or
>      ineffective)?
>         reboot to previous linux-image-6.12.41+deb13-amd64 makes networking
> work again.
> 
>    * What was the outcome of this action?
> 
>         Seems like TCP connections do not work beyond the first connection.
>         For example, two apt-get update commands fail on the second one:
> 
> root@marcamalaga:~# uname -r
> 6.12.73+deb13-amd64
> root@marcamalaga:~# date
> Wed Mar 11 10:22:19 AM CET 2026
> root@marcamalaga:~# apt-get update
> Get:1 http://security.debian.org/debian-security trixie-security InRelease
> [43.4 kB]
> Hit:2 http://ftp.es.debian.org/debian trixie InRelease
> Get:3 http://ftp.es.debian.org/debian trixie-updates InRelease [47.3 kB]
> Hit:4 https://www.deb-multimedia.org trixie InRelease
> Fetched 90.7 kB in 1s (152 kB/s)
> Reading package lists... Done
> root@marcamalaga:~#
> root@marcamalaga:~# date
> Wed Mar 11 10:22:28 AM CET 2026
> root@marcamalaga:~#
> root@marcamalaga:~# apt-get update
> Hit:1 http://security.debian.org/debian-security trixie-security InRelease
> Hit:2 http://ftp.es.debian.org/debian trixie InRelease
> Hit:3 http://ftp.es.debian.org/debian trixie-updates InRelease
> Ign:4 https://www.deb-multimedia.org trixie InRelease
> Ign:4 https://www.deb-multimedia.org trixie InRelease
> Ign:4 https://www.deb-multimedia.org trixie InRelease
> Err:4 https://www.deb-multimedia.org trixie InRelease
>   Cannot initiate the connection to www.deb-multimedia.org:443
> (2607:5300:120:e71::1). - connect (101: Network is unreachable) Could not
> connect to www.deb-multimedia.org:443 (158.69.254.113), connection timed out
>   Cannot initiate the connection to www.deb-multimedia.org:443
> (2607:5300:120:e71::1). - connect (101: Network is unreachable)
> Reading package lists... Done
> W: Failed to fetch https://www.deb-multimedia.org/dists/trixie/InRelease
> Cannot initiate the connection to www.deb-multimedia.org:443
> (2607:5300:120:e71::1). - connect (101: Network is unreachable)
> W: Some index files failed to download. They have been ignored, or old ones
> used instead.
> root@marcamalaga:~#
> 
>         Similarly, for illustration, here two probes of an HTTP stream, works
> only once:
> 
> administrator@marcamalaga:~$ uname -r
> 6.12.73+deb13-amd64
> administrator@marcamalaga:~$ date
> Wed Mar 11 10:19:23 AM CET 2026
> administrator@marcamalaga:~$ ffprobe http://10.20.10.80:8130/malagafmmobile
> ffprobe version 7.1.3 Copyright (c) 2007-2025 the FFmpeg developers
>   built with gcc 14 (Debian 14.2.0-19)
>   configuration: --disable-decoder=amrnb --disable-gnutls --disable-liblensfun
> --disable-libopencv --disable-podpages --disable-sndio --disable-stripping
> --disable-omx --enable-avfilter --enable-chromaprint --enable-frei0r --enable-
> gcrypt --enable-gpl --enable-ladspa --enable-libaom --enable-libaribb24
> --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-
> libcdio --enable-libcodec2 --enable-libdav1d --enable-libdavs2 --enable-
> libdc1394 --enable-libdrm --enable-libdvdnav --enable-libdvdread --enable-
> libfdk-aac --enable-libflite --enable-libfontconfig --enable-libfreetype
> --enable-libfribidi --enable-libgme --enable-libgsm --enable-libharfbuzz
> --enable-libiec61883 --enable-libilbc --enable-libjack --enable-libjxl
> --enable-libklvanc --enable-libkvazaar --enable-libmp3lame --enable-libmysofa
> --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264
> --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libplacebo
> --enable-libpulse --enable-librabbitmq --enable-librist --enable-librsvg
> --enable-librubberband --enable-libshine --enable-libsmbclient --enable-
> libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt 
> --enable-libsvtav1
> --enable-libtesseract --enable-libtheora --enable-libtwolame --enable-
> libvidstab --enable-libvmaf --enable-libvo-amrwbenc --enable-libvorbis
> --enable-libvpx --enable-libwebp --enable-libwebp --enable-libx264 --enable-
> libx265 --enable-libxavs2 --enable-libxml2 --enable-libxvid --enable-libzimg
> --enable-libzmq --enable-libzvbi --enable-lv2 --enable-nonfree --enable-openal
> --enable-opencl --enable-opengl --enable-openssl --enable-postproc --enable-
> pthreads --enable-shared --enable-version3 --incdir=/usr/include/x86_64-linux-
> gnu --libdir=/usr/lib/x86_64-linux-gnu --prefix=/usr --toolchain=hardened
> --enable-vaapi --enable-libvpl --cc=x86_64-linux-gnu-gcc --cxx=x86_64-linux-
> gnu-g++ --disable-altivec --shlibdir=/usr/lib/x86_64-linux-gnu
>   libavutil      59. 39.100 / 59. 39.100
>   libavcodec     61. 19.101 / 61. 19.101
>   libavformat    61.  7.100 / 61.  7.100
>   libavdevice    61.  3.100 / 61.  3.100
>   libavfilter    10.  4.100 / 10.  4.100
>   libswscale      8.  3.100 /  8.  3.100
>   libswresample   5.  3.100 /  5.  3.100
>   libpostproc    58.  3.100 / 58.  3.100
> Input #0, mp3, from 'http://10.20.10.80:8130/malagafmmobile':
>   Metadata:
>     icy-br          : 170
>     icy-description : : Radio MARCA MA :
>     icy-genre       : Sport Radio
>     icy-name        : : Radio MARCA MA :
>     icy-pub         : 1
>     icy-url         : www.radiomarca.com
>     StreamTitle     :
>   Duration: N/A, start: 0.000000, bitrate: 191 kb/s
>   Stream #0:0: Audio: mp3 (mp3float), 44100 Hz, stereo, fltp, 191 kb/s
> administrator@marcamalaga:~$
> administrator@marcamalaga:~$
> administrator@marcamalaga:~$ date
> Wed Mar 11 10:19:44 AM CET 2026
> administrator@marcamalaga:~$ ffprobe http://10.20.10.80:8130/malagafmmobile
> ffprobe version 7.1.3 Copyright (c) 2007-2025 the FFmpeg developers
>   built with gcc 14 (Debian 14.2.0-19)
>   configuration: --disable-decoder=amrnb --disable-gnutls --disable-liblensfun
> --disable-libopencv --disable-podpages --disable-sndio --disable-stripping
> --disable-omx --enable-avfilter --enable-chromaprint --enable-frei0r --enable-
> gcrypt --enable-gpl --enable-ladspa --enable-libaom --enable-libaribb24
> --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-
> libcdio --enable-libcodec2 --enable-libdav1d --enable-libdavs2 --enable-
> libdc1394 --enable-libdrm --enable-libdvdnav --enable-libdvdread --enable-
> libfdk-aac --enable-libflite --enable-libfontconfig --enable-libfreetype
> --enable-libfribidi --enable-libgme --enable-libgsm --enable-libharfbuzz
> --enable-libiec61883 --enable-libilbc --enable-libjack --enable-libjxl
> --enable-libklvanc --enable-libkvazaar --enable-libmp3lame --enable-libmysofa
> --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264
> --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libplacebo
> --enable-libpulse --enable-librabbitmq --enable-librist --enable-librsvg
> --enable-librubberband --enable-libshine --enable-libsmbclient --enable-
> libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt 
> --enable-libsvtav1
> --enable-libtesseract --enable-libtheora --enable-libtwolame --enable-
> libvidstab --enable-libvmaf --enable-libvo-amrwbenc --enable-libvorbis
> --enable-libvpx --enable-libwebp --enable-libwebp --enable-libx264 --enable-
> libx265 --enable-libxavs2 --enable-libxml2 --enable-libxvid --enable-libzimg
> --enable-libzmq --enable-libzvbi --enable-lv2 --enable-nonfree --enable-openal
> --enable-opencl --enable-opengl --enable-openssl --enable-postproc --enable-
> pthreads --enable-shared --enable-version3 --incdir=/usr/include/x86_64-linux-
> gnu --libdir=/usr/lib/x86_64-linux-gnu --prefix=/usr --toolchain=hardened
> --enable-vaapi --enable-libvpl --cc=x86_64-linux-gnu-gcc --cxx=x86_64-linux-
> gnu-g++ --disable-altivec --shlibdir=/usr/lib/x86_64-linux-gnu
>   libavutil      59. 39.100 / 59. 39.100
>   libavcodec     61. 19.101 / 61. 19.101
>   libavformat    61.  7.100 / 61.  7.100
>   libavdevice    61.  3.100 / 61.  3.100
>   libavfilter    10.  4.100 / 10.  4.100
>   libswscale      8.  3.100 /  8.  3.100
>   libswresample   5.  3.100 /  5.  3.100
>   libpostproc    58.  3.100 / 58.  3.100
> [tcp @ 0x561036562fc0] Connection to tcp://10.20.10.80:8130 failed: Connection
> timed out
> http://10.20.10.80:8130/malagafmmobile: Connection timed out
> 
>         The problem happens on VIRTUAL MACHINES (PROXMOX 9 guests) using 
> virtio
> drivers.
>         I have experienced same behaviour on dist-upgraded Bookworm VMs with
> latest kernel.
>         All VMs worked as expected and are inproduction without any issues
> before dist-upgrading them.
>         Machines still not dist-upgraded work flawless.
>         The problem is fully consistent with kernel upgrade... just reboot to
> previous kernel to resume work.
> 
>    * What outcome did you expect instead?
>         Regular operation of the networking stack

I suspect this then depends on the underlaying virtualisation,
otherwise we would have I think more such reports. As you have a
fairly straightforward reproducer, can you please bisect the changes
between 6.12.41 and 6.12.73? (Ideally you test first the kernels
inbetween up to 6.12.69-1 so we have a closer range, you can get other
images earlier in the archive from the snapshots service. This should
be done as first step, because there were a a couple of releases in
Debian between 6.12.41-1 and 6.12.73-1). So assume you have 6.12.69-1
which is good, and 6.12.73-1 which is not anymore, bisecting would
involve:

    git clone --single-branch -b linux-6.12.y 
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git
    cd linux-stable
    git checkout v6.12.69
    cp /boot/config-$(uname -r) .config
    yes '' | make localmodconfig
    make savedefconfig
    mv defconfig arch/x86/configs/my_defconfig

    # test 6.12.69 to ensure this is "good"
    make my_defconfig
    make -j $(nproc) bindeb-pkg
    ... install the resulting .deb package and confirm problem does not exist

    # test 6.12.73 to ensure this is "bad"
    git checkout v6.12.73
    make my_defconfig
    make -j $(nproc) bindeb-pkg
    ... install the resulting .deb package and confirm the problem exists.

With that confirmed, the bisection can start:

    git bisect start
    git bisect good v6.12.69
    git bisect bad v6.12.73

In each bisection step git checks out a state between the oldest
known-bad and the newest known-good commit. In each step test using:

    make my_defconfig
    make -j $(nproc) bindeb-pkg
    ... install, verify if problem exists

and if the problem is hit run:

    git bisect bad

and if the problem doesn't trigger run:

    git bisect good

. Please pay attention to always select the just built kernel for
booting, it won't always be the default kernel picked up by grub.

Iterate until git announces to have identified the first bad commit.

Then provide the output of

    git bisect log

In the course of the bisection you might have to uninstall previous
kernels again to not exhaust the disk space in /boot. Also in the end
uninstall all self-built kernels again.

Regards,
Salvatore

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