Segfault in app_indicator_set_icon_full [patch attached]

Bug #1867996 reported by Paul G on 2020-03-18
This bug affects 10 people
Affects Status Importance Assigned to Milestone
libappindicator (Arch Linux)
libappindicator (Ubuntu)
Marco Trevisan (Treviño)

Bug Description

[ Impact ]

Discord and several other applications using libappindicator are widely reported to have been crashing for several years. See: (and others)

[ Test case ]

- Run discord application
- It must not crash in ubuntu (or when indicators are enabled)

[ Regression potential ]

Very low, icons might not appear in some cases, if any.


This is the backtrace:
(gdb) bt full
#0 0x00007fe1d5d2e00e in () at /app/lib/
#1 0x00007fe1f5a6f3c5 in g_closure_invoke () at /lib/
#2 0x00007fe1f5a813d2 in () at /lib/
#3 0x00007fe1f5a8a02c in g_signal_emit_valist () at /lib/
#4 0x00007fe1f5a8a40f in g_signal_emit () at /lib/
#5 0x00007fe1d5d2ed4f in app_indicator_set_icon_full () at /app/lib/
#6 0x000000000077851a in ()
#7 0x0000000001de7123 in ()
#8 0x0000000001e4bd4e in ()
#9 0x0000000001e6e34c in ()
#10 0x0000000001e6e668 in ()
#11 0x0000000001e6e9cb in ()
#12 0x0000000001df971a in ()
#13 0x00007fe1f354b1c7 in g_main_context_dispatch () at /lib/
#14 0x00007fe1f354b430 in () at /lib/
#15 0x00007fe1f354b4dc in g_main_context_iteration () at /lib/
#16 0x0000000001df9606 in ()
#17 0x0000000001e6e0e7 in ()
#18 0x0000000001e29570 in ()
#19 0x0000000000c37ec8 in ()
#20 0x0000000000c37d15 in ()
#21 0x0000000000c1da7d in ()
#22 0x0000000000a9282e in ()
#23 0x00000000007892d4 in ()
#24 0x00000000007896e0 in ()
#25 0x0000000003b830a3 in main ()

Happens in all versions of libappindicator built from latest sources available on launchpad.

I ran into the issue yesterday when installing Discord for the first time. I have tracked the problem down to libappindicator passing in an extra vararg item to g_signal_emit that the signal's definition in libappindicator was not declaring, causing the crash you see above in gobject's g_signal dispatch machinery.

Patch is attached.

I am presuming this is 'upstream' for libappindicator, whatever that may mean for what appears to be an unmaintained project. If it is not, and since it is an Ubuntu/Canonical-sourced project originally, I respectfully request that you assist in upstreaming it since this bug is causing severe breakage for users across all distros.

Paul G (paulieg) wrote :

The attachment "Stop passing in undeclared boolean vararg" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]

tags: added: patch
Paul G (paulieg) wrote :

So, the patch is wrong. It fixes *a* bug, but not *the* bug. There appear to be multiple g_signal_emit calls that don't match the definition of the g_signals they're emitting. See:

Unless I'm missing something, they all need to be fixed. I will audit them all, put together a patch, test it and report on results. Absent feedback from someone who actually knows g_signals and gobject in general, this ought to show whether I've misunderstood something or not.

Paul G (paulieg) wrote :

I've gone through the code and cleaned up all g_signal_emit and g_signal_new calls so they correspond with each other and make sense. No external API changes. Wrote up a simple test program to exercise the basic functionality, and used things like blueman-tray to confirm other edge functionality works. No longer crashes, signals to change status work and so on New patch attached.

Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in libappindicator (Ubuntu):
status: New → Confirmed
Ash Holland (sersorrel) wrote :

fwiw, that patch (or at least a slightly modified version which applies on the Ubuntu 18.04 libappindicator) appears to fix the Discord segfaults for me, and also looks correct from my reading of the gobject documentation.

Ash Holland (sersorrel) wrote :

correction: I also need to apply this patch in order to fix the segfaults for me.

Ian Whitlock (gigawhitlocks) wrote :

Applying both segfault_fix.patch and n_elements.patch seems to have cleared up these segfaults for me.

Changed in libappindicator (Ubuntu):
assignee: nobody → Marco Trevisan (Treviño) (3v1n0)
status: Confirmed → Fix Committed
description: updated
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package libappindicator - 12.10.1+20.04.20200408.1-0ubuntu1

libappindicator (12.10.1+20.04.20200408.1-0ubuntu1) focal; urgency=medium

  [ Paul G ]
  * app-indicator: Don't pass unexpected parameter to signal emissions
    (LP: #1867996)

  [ Ash Holland ]
  * app-indicator: Only check for item numbers when iterating array
    (LP: #1867996)

 -- Marco Trevisan (Treviño) <> Wed, 08 Apr 2020 18:58:49 +0000

Changed in libappindicator (Ubuntu):
status: Fix Committed → Fix Released
Ash Holland (sersorrel) wrote :

It seems like there is still an unresolved issue with Discord after applying these patches:

though I don't know if the issue is caused by libappindicator or if it's a Discord problem that's exposed by the libappindicator-induced crashes being fixed.

Zach (despawned) wrote :


Yes, what Ash linked is correct. I am the person who's comment is linked in Ash's comment, and after applying these patches, a new bug is created. After being in a voice call for a long period of time, discord animations will start to progressively lag severely when audio input is received. When you are not talking (mic activated) or your mic is muted, the lag does not occur, however, when typing and talking it is SEVERE. There must be something in these patches that causes high resource consumption (not necessarily ram/cpu) when voice is activated for long periods of time.

Paul G (paulieg) wrote :

This is getting far too confusing because multiple patches for multiple bugs are being conflated. I produced a fairly straightforward patch that fixed an issue I directly saw in people's backtraces, and other issues I identified that are similar. This is what this bug report is for.

The later patch that supposedly fixes something else is not mine, hasn't been tested by me, purports to solve an issue I personally haven't seen in a way that has no similarities to the bug I opened this report for (other than it occurs in Discord as well). Please open a separate bug report with backtraces that demonstrate *that* problem, and with *that* patch attached.

This avoids confusion and possible backing out of my patch together with the second, unrelated patch in case said unrelated patch has introduced a new problem.

Both patches have been applied, so no need for further bug. cfr

TimSC (timsc) wrote :

I created PPA for libappindicator trunk (on 2020-06-02) for 18.04 and 20.04, as in interim measure: and this seems to work for me with discord (at least for a 2 hour call).

Strangely, my system didn't detect it as a update, so I manually did:

sudo apt-get install libappindicator1=12.10.1+18.04.20200601.1-0ubuntu1

Probably something to do with package version numbers but I don't understand what.

The fix is already in 20.04, while for 18.04 you can use the packages in while the SRU team looks at the fix in queue for some time now.

Hello Paul, or anyone else affected,

Accepted libappindicator into bionic-proposed. The package will build now and be available at in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-bionic to verification-done-bionic. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-bionic. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

Changed in libappindicator (Ubuntu Bionic):
status: New → Fix Committed
tags: added: verification-needed verification-needed-bionic
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