crash (startup, flatpak x64)

[secretmango]

           PID: 22196 (amule)
           UID: 1002 (user)
           GID: 100 (users)
        Signal: 6 (ABRT)
     Timestamp: Fri 2026-06-26 20:00:30 CEST (4s ago)
  Command Line: amule
    Executable: /app/bin/amule
 Control Group: /user.slice/user-1002.slice/user@1002.service/app.slice/app-flatpak-org.amule.aMule-212657030.scope
          Unit: user@1002.service
     User Unit: app-flatpak-org.amule.aMule-212657030.scope
         Slice: user-1002.slice
     Owner UID: 1002 (user)
       Boot ID: 19e7235356a84838abd205a3edde512d
    Machine ID: da46997997df4405b979152f4b4eb448
      Hostname: PC
       Storage: /var/lib/systemd/coredump/core.amule.1002.19e7235356a84838abd205a3edde512d.22196.1782496830000000.zst (present)
  Size on Disk: 6.6M
       Message: Process 22196 (amule) of user 1002 dumped core.
                
                Module /usr/lib/x86_64-linux-gnu/libglycin-2.so.0 without build-id.
                Module /usr/lib/x86_64-linux-gnu/libglycin-2.so.0
                Stack trace of thread 2:
                #0  0x000077573169d61c n/a (/usr/lib/x86_64-linux-gnu/libc.so.6 + 0x9c61c)
                #1  0x00007757316433be n/a (/usr/lib/x86_64-linux-gnu/libc.so.6 + 0x423be)
                #2  0x000077573162a8ed n/a (/usr/lib/x86_64-linux-gnu/libc.so.6 + 0x298ed)
                #3  0x000077573349f0b8 n/a (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.8800.1 + 0x250b8)
                #4  0x00007757335116d2 n/a (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.8800.1 + 0x976d2)
                #5  0x0000775732dead89 n/a (/usr/lib/x86_64-linux-gnu/libgtk-3.so.0.2420.32 + 0x1ead89)
                #6  0x0000775732deb58a n/a (/usr/lib/x86_64-linux-gnu/libgtk-3.so.0.2420.32 + 0x1eb58a)
                #7  0x0000775732deb604 n/a (/usr/lib/x86_64-linux-gnu/libgtk-3.so.0.2420.32 + 0x1eb604)
                #8  0x0000775732d4a9fc n/a (/usr/lib/x86_64-linux-gnu/libgtk-3.so.0.2420.32 + 0x14a9fc)
                #9  0x0000775732cf01d3 n/a (/usr/lib/x86_64-linux-gnu/libgtk-3.so.0.2420.32 + 0xf01d3)
                #10 0x0000775732d4a9fc n/a (/usr/lib/x86_64-linux-gnu/libgtk-3.so.0.2420.32 + 0x14a9fc)
                #11 0x0000775732ed2bdb n/a (/usr/lib/x86_64-linux-gnu/libgtk-3.so.0.2420.32 + 0x2d2bdb)
                #12 0x0000775732ecf606 n/a (/usr/lib/x86_64-linux-gnu/libgtk-3.so.0.2420.32 + 0x2cf606)
                #13 0x0000775732ecfcfc n/a (/usr/lib/x86_64-linux-gnu/libgtk-3.so.0.2420.32 + 0x2cfcfc)
                #14 0x0000775732ecfe5b n/a (/usr/lib/x86_64-linux-gnu/libgtk-3.so.0.2420.32 + 0x2cfe5b)
                #15 0x00005af3c7f72e71 n/a (/app/bin/amule + 0x6e5e71)
                #16 0x00005af3c7f72f0c n/a (/app/bin/amule + 0x6e5f0c)
                #17 0x00005af3c8061e82 n/a (/app/bin/amule + 0x7d4e82)
                #18 0x00005af3c8062068 n/a (/app/bin/amule + 0x7d5068)
                #19 0x00005af3c8062288 n/a (/app/bin/amule + 0x7d5288)
                #20 0x00005af3c7f8c753 n/a (/app/bin/amule + 0x6ff753)
                #21 0x00005af3c7eb2f0d n/a (/app/bin/amule + 0x625f0d)
                #22 0x00005af3c7d8bd57 n/a (/app/bin/amule + 0x4fed57)
                #23 0x00005af3c7d203d4 n/a (/app/bin/amule + 0x4933d4)
                #24 0x00005af3c7d066e4 n/a (/app/bin/amule + 0x4796e4)
                #25 0x00005af3c7d06ac0 n/a (/app/bin/amule + 0x479ac0)
                #26 0x00005af3c7c16871 n/a (/app/bin/amule + 0x389871)
                #27 0x00005af3c7d06c68 n/a (/app/bin/amule + 0x479c68)
                #28 0x00005af3c819f4d8 n/a (/app/bin/amule + 0x9124d8)
                #29 0x00005af3c7b43b18 n/a (/app/bin/amule + 0x2b6b18)
                #30 0x000077573162c975 n/a (/usr/lib/x86_64-linux-gnu/libc.so.6 + 0x2b975)
                #31 0x000077573162ca28 n/a (/usr/lib/x86_64-linux-gnu/libc.so.6 + 0x2ba28)
                #32 0x00005af3c7b630a5 n/a (/app/bin/amule + 0x2d60a5)
                ELF object binary architecture: AMD x86-64

aMule worked fine after the 3.0.1 update installed as flatpak.

Now after a NixOS system update, whenever I start the aMule flatpak from the app menu, it gives me that crash.

$ flatpak run org.amule.aMule
 2026-06-26 20:03:52: Initialising aMule 3.0.1 compiled with wxGTK3 v3.2.6 and Boost 1.87
 2026-06-26 20:03:52: Checking if there is an instance already running...
 2026-06-26 20:03:52: No other instances are running.
 2026-06-26 20:03:52: ListenSocket: OK

(org.amule.aMule:2): Gtk-WARNING **: 20:03:52.771: Could not load a pixbuf from icon theme.
This may indicate that pixbuf loaders or the mime database could not be found.
**
Gtk:ERROR:../gtk/gtkiconhelper.c:495:ensure_surface_for_gicon: assertion failed (error == NULL): Failed to load /run/host/share/icons/breeze-dark/status/16@2x/image-missing.svg: Loader process exited early with status '1'Command:
 env -i XDG_RUNTIME_DIR="/run/user/1002" "flatpak-spawn" "--sandbox" "--watch-bus" "--directory=/" "--forward-fd=21" "prlimit" "--as=8754973900" "/usr/libexec/glycin-loaders/2+/glycin-svg" "--dbus-fd" "21" (gdk-pixbuf-error-quark, 0)
Bail out! Gtk:ERROR:../gtk/gtkiconhelper.c:495:ensure_surface_for_gicon: assertion failed (error == NULL): Failed to load /run/host/share/icons/breeze-dark/status/16@2x/image-missing.svg: Loader process exited early with status '1'Command:  env -i XDG_RUNTIME_DIR="/run/user/1002" "flatpak-spawn" "--sandbox" "--watch-bus" "--directory=/" "--forward-fd=21" "prlimit" "--as=8754973900" "/usr/libexec/glycin-loaders/2+/glycin-svg" "--dbus-fd" "21" (gdk-pixbuf-error-quark, 0)

I am using the following flatpak permission override (! is for disabled). Removing the permission override does not change anything.

[Context]
devices=!dri;
filesystems=!home;~/.aMule:create;xdg-download/aMule:create;
sockets=!fallback-x11;

[secretmango]

the same happens when running the previous git version, which is odd

flatpak run org.amule.aMule
 2026-06-26 20:10:25: Initialising aMule GIT compiled with wxGTK3 v3.2.6 and Boost 1.87 (Snapshot: rev. 3.0.0-10-g5017da527)
 2026-06-26 20:10:25: Checking if there is an instance already running...
 2026-06-26 20:10:25: No other instances are running.
 2026-06-26 20:10:26: ListenSocket: OK

(org.amule.aMule:2): Gtk-WARNING **: 20:10:26.337: Could not load a pixbuf from icon theme.
This may indicate that pixbuf loaders or the mime database could not be found.
**
Gtk:ERROR:../gtk/gtkiconhelper.c:495:ensure_surface_for_gicon: assertion failed (error == NULL): Failed to load /run/host/share/icons/breeze-dark/status/16@2x/image-missing.svg: Loader process exited early with status '1'Command:
 env -i XDG_RUNTIME_DIR="/run/user/1002" "flatpak-spawn" "--sandbox" "--watch-bus" "--directory=/" "--forward-fd=21" "prlimit" "--as=8300049203" "/usr/libexec/glycin-loaders/2+/glycin-svg" "--dbus-fd" "21" (gdk-pixbuf-error-quark, 0)
Bail out! Gtk:ERROR:../gtk/gtkiconhelper.c:495:ensure_surface_for_gicon: assertion failed (error == NULL): Failed to load /run/host/share/icons/breeze-dark/status/16@2x/image-missing.svg: Loader process exited early with status '1'Command:  env -i XDG_RUNTIME_DIR="/run/user/1002" "flatpak-spawn" "--sandbox" "--watch-bus" "--directory=/" "--forward-fd=21" "prlimit" "--as=8300049203" "/usr/libexec/glycin-loaders/2+/glycin-svg" "--dbus-fd" "21" (gdk-pixbuf-error-quark, 0)

before the system update of my underlying OS it worked fine

[secretmango]

important to note that Nicotine+ flatpak still works, and also uses GTK3

debugging I attempted:

flatpak run --env=GTK_ICON_THEME=Adwaita org.amule.aMule                                                                                                               ✘ 134
 2026-06-26 20:20:28: Initialising aMule 3.0.1 compiled with wxGTK3 v3.2.6 and Boost 1.87
 2026-06-26 20:20:28: Checking if there is an instance already running...
 2026-06-26 20:20:28: No other instances are running.
 2026-06-26 20:20:29: ListenSocket: OK

(org.amule.aMule:2): Gtk-WARNING **: 20:20:29.470: Could not load a pixbuf from icon theme.
This may indicate that pixbuf loaders or the mime database could not be found.
**
Gtk:ERROR:../gtk/gtkiconhelper.c:495:ensure_surface_for_gicon: assertion failed (error == NULL): Failed to load /run/host/share/icons/breeze-dark/status/16@2x/image-missing.svg: Loader process exited early with status '1'Command:
 env -i XDG_RUNTIME_DIR="/run/user/1002" "flatpak-spawn" "--sandbox" "--watch-bus" "--directory=/" "--forward-fd=21" "prlimit" "--as=7699906560" "/usr/libexec/glycin-loaders/2+/glycin-svg" "--dbus-fd" "21" (gdk-pixbuf-error-quark, 0)
Bail out! Gtk:ERROR:../gtk/gtkiconhelper.c:495:ensure_surface_for_gicon: assertion failed (error == NULL): Failed to load /run/host/share/icons/breeze-dark/status/16@2x/image-missing.svg: Loader process exited early with status '1'Command:  env -i XDG_RUNTIME_DIR="/run/user/1002" "flatpak-spawn" "--sandbox" "--watch-bus" "--directory=/" "--forward-fd=21" "prlimit" "--as=7699906560" "/usr/libexec/glycin-loaders/2+/glycin-svg" "--dbus-fd" "21" (gdk-pixbuf-error-quark, 0)

I also tried flatpak install org.gtk.Gtk3theme.Breeze and flatpak run --env=GTK_ICON_THEME=Breeze org.amule.aMule but no change

[got3nks]

Thanks — those two details pin it down.

• Same crash on an older aMule git build → not an aMule-version regression; it's environmental, triggered by the NixOS update (as you found).
• Nicotine+ still working is the key clue. The crash isn't in GTK3 itself — it's in glycin, the image/SVG loader that newer GNOME runtimes use, which runs each loader as a sandboxed subprocess (glycin-svg). aMule's flatpak is built on a very recent runtime (org.gnome.Platform//50) that loads SVG icons via glycin; Nicotine+ is almost certainly on an older runtime where SVGs load in-process, so it never hits the sandboxed loader that's failing on your machine.

Could you confirm by comparing the runtimes?

flatpak info org.amule.aMule | grep -i runtime
flatpak info <nicotine-app-id> | grep -i runtime

The underlying break is glycin's nested loader sandbox failing to spawn on your updated NixOS — it needs unprivileged user namespaces + a working portal, which a system update can change. Worth trying, in order:

1. Reset overrides and retest from a terminal, pasting the output: flatpak override --user --reset org.amule.aMule. Your !dri / !home / !fallback-x11 overrides tighten the sandbox and can block the loader subprocess.
2. flatpak update (make sure org.gnome.Platform//50 is fully pulled).
3. Confirm xdg-desktop-portal is running and check whether the update changed unprivileged-user-namespace settings.

If it's the runtime/glycin difference, the fix is on the NixOS/glycin side — and we'll also look at whether the runtime pin needs revisiting.

[secretmango]

Runtime: org.gnome.Platform/x86_64/50
Runtime: org.gnome.Platform/x86_64/50

both use the same runtime

$ flatpak override --user --reset org.amule.aMule
$ flatpak run org.amule.aMule
 2026-06-26 20:29:27: Initialising aMule 3.0.1 compiled with wxGTK3 v3.2.6 and Boost 1.87
 2026-06-26 20:29:27: Checking if there is an instance already running...
 2026-06-26 20:29:27: No other instances are running.
 2026-06-26 20:29:27: ListenSocket: Ok.

(org.amule.aMule:2): Gtk-WARNING **: 20:29:27.838: Could not load a pixbuf from icon theme.
This may indicate that pixbuf loaders or the mime database could not be found.
**
Gtk:ERROR:../gtk/gtkiconhelper.c:495:ensure_surface_for_gicon: assertion failed (error == NULL): Failed to load /run/host/share/icons/breeze-dark/status/16@2x/image-missing.svg: Loader process exited early with status '1'Command:
 env -i XDG_RUNTIME_DIR="/run/user/1002" "flatpak-spawn" "--sandbox" "--watch-bus" "--directory=/" "--forward-fd=21" "prlimit" "--as=7092486144" "/usr/libexec/glycin-loaders/2+/glycin-svg" "--dbus-fd" "21" (gdk-pixbuf-error-quark, 0)
Bail out! Gtk:ERROR:../gtk/gtkiconhelper.c:495:ensure_surface_for_gicon: assertion failed (error == NULL): Failed to load /run/host/share/icons/breeze-dark/status/16@2x/image-missing.svg: Loader process exited early with status '1'Command:  env -i XDG_RUNTIME_DIR="/run/user/1002" "flatpak-spawn" "--sandbox" "--watch-bus" "--directory=/" "--forward-fd=21" "prlimit" "--as=7092486144" "/usr/libexec/glycin-loaders/2+/glycin-svg" "--dbus-fd" "21" (gdk-pixbuf-error-quark, 0)

but as said, I already tried that.

I already tried installing GTK3 breeze icons as flatpak and overriding the icon theme path, with no change. it must be glycin somehow.

there dont seem to be recent changes in the glycin package

• glycin tumbnailer
• glycin-loaders

[got3nks]

Same runtime on both is useful — it rules out a runtime-version difference. Working hypothesis: the failing piece is glycin's sandboxed SVG loader (glycin-svg via flatpak-spawn --sandbox, exiting 1), and aMule reaches it because wxGTK pulls icons from the host theme (→ the image-missing.svg fallback) where Nicotine+ ships its own icons and never does. But before concluding anything, two checks to confirm where it actually breaks:

1. Does the nested sandbox glycin relies on work at all on your host?

flatpak run --command=sh org.amule.aMule -c 'flatpak-spawn --sandbox echo ok; echo exit=$?'

2. Does another glycin consumer fail the same way? The GNOME image viewer (Loupe) uses glycin directly — open any SVG in it:

flatpak install flathub org.gnome.Loupe

If Loupe also can't render an SVG, glycin is broken host-wide (not aMule-specific); if it renders fine, the breakage is narrower and we look closer at the path aMule triggers.

Those two will tell us whether this is host/glycin or something to address on the aMule side — let's confirm before changing anything.

[secretmango]

flatpak run --command=sh org.amule.aMule -c 'flatpak-spawn --sandbox echo ok; echo exit=$?'
bwrap: execvp echo: No such file or directory
exit=1

indeed, GNOME loupe fails to open the SVG

Loader process exited early with status '1'Command:
 env -i XDG_RUNTIME_DIR="/run/user/1002" "flatpak-spawn" "--sandbox" "--watch-bus" "--directory=/" "--forward-fd=37" "prlimit" "--as=6529780940" "/usr/libexec/glycin-loaders/2+/glycin-svg" "--dbus-fd" "37"

[got3nks]

That second test settles it: Loupe fails identically — same glycin-svg … Loader process exited early with status '1'. Loupe uses glycin directly and has nothing to do with aMule's icon handling, so this is a host-wide glycin SVG-loader failure on your NixOS setup, not an aMule bug. aMule just trips it at startup because wxGTK pulls icons from the host theme; Nicotine+ ships its own and never reaches the loader.

(The echo test was a red herring — bwrap did launch and then couldn't find the echo binary because flatpak-spawn --sandbox runs with a stripped PATH. glycin invokes its loader by absolute path, so that one doesn't apply. Loupe is the real confirmation.)

Since the regression came in with your system update and reproduces in Loupe, this is a glycin / nixpkgs issue — Loupe gives you a clean, aMule-independent reproducer to file upstream (glycin: https://gitlab.gnome.org/sophie-h/glycin, and/or nixpkgs). The trigger is most likely something under glycin that the update moved (bubblewrap / kernel / landlock), even though the glycin package itself didn't change.

On the aMule side we're the canary, not the cause — but I'll keep this open to track a hardening: bundling our own status-icon set (the way Nicotine+ does) so aMule doesn't depend on the host theme and a broken host SVG loader can't take down startup. That won't fix glycin, but it'd make aMule resilient to it.

[secretmango]

NixOS/nixpkgs#535787