noise crashed with SIGSEGV in magazine_chain_pop_head()

[Jaroslav-huna]

No clue.

ProblemType: Crash
DistroRelease: elementary OS 0.2
Package: noise 0.4+r1167-0+pkg29~precise1 [origin: LP-PPA-elementary-os-daily]
ProcVersionSignature: Ubuntu 3.2.0-32.51-generic 3.2.30
Uname: Linux 3.2.0-32-generic x86_64
ApportVersion: 2.0.1-0ubuntu14+elementary3~precise1
Architecture: amd64
CrashDB: noise
Date: Wed Nov 7 16:14:15 2012
ExecutablePath: /usr/bin/noise
InstallationMedia: elementary OS 0.2 "Luna" - Build amd64 LIVE Binary 20121101-17:25
ProcCmdline: noise
ProcEnviron:
 PATH=(custom, no user)
 LANG=cs_CZ.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x7fd628ba5e2d <g_slice_alloc+477>: mov 0x8(%rax),%rbx
 PC (0x7fd628ba5e2d) ok
 source "0x8(%rax)" (0x00000009) not located in a known VMA region (needed readable region)!
 destination "%rbx" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: noise
StacktraceTop:
 g_slice_alloc () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libpango-1.0.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libpango-1.0.so.0
 pango_layout_get_pixel_extents () from /usr/lib/x86_64-linux-gnu/libpango-1.0.so.0
 pango_layout_get_pixel_size () from /usr/lib/x86_64-linux-gnu/libpango-1.0.so.0
Title: noise crashed with SIGSEGV in g_slice_alloc()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo

[RabbitBot (rabbitbot-a)]

StacktraceTop:
 magazine_chain_pop_head (magazine_chunks=0x14fe030) at /build/buildd/glib2.0-2.32.3/./glib/gslice.c:528
 thread_memory_magazine1_alloc (ix=<optimized out>, tmem=<optimized out>) at /build/buildd/glib2.0-2.32.3/./glib/gslice.c:835
 g_slice_alloc (mem_size=72) at /build/buildd/glib2.0-2.32.3/./glib/gslice.c:994
 pango_layout_line_new (layout=0x23cc810) at /build/buildd/pango1.0-1.30.0/./pango/pango-layout.c:4713
 process_line (state=0x7fff086ad6a0, layout=0x23cc810) at /build/buildd/pango1.0-1.30.0/./pango/pango-layout.c:3556

[Cody Garver (codygarver)]

From another bug: "I submitted this yesterday and was told my packages where outdated. I did an sudo apt-get update and upgrade today to get the newest packages, still having the same bug, Noise crashes after playing 7 to 30 secs of a song, I did notice something today, if I keep the noise window open and active, Noise does not crash, but if I minimize or leave it in background some seconds later it crashes..."

[Victor Martinez (victored)]

This is the thread-safety issue I was talking about the other day. It seems a draw operation is being triggered from a thread other than GTK+'s main thread (which is the same default thread of the app). This happens after calling LibraryManager.update_media(), so we must check that no UI handler is fired from a separate thread.

The code to blame is the following:

LINE 587 - LibraryManager.vala:

    private async void update_smart_playlists_async () {
        SourceFunc callback = update_smart_playlists_async.callback;

        // Playlist.update_library() will fire the playlists' media_added() and media_removed() signals, which
        // trigger an update in PlaylistViewWrapper (this is the source of the redraw).
        Threads.add (() => {
            lock (_smart_playlists) {
                foreach (var p in smart_playlists ()) {
                    lock (_media) {
                        p.update_library (media ());
                    }
                }
            }
            Idle.add ((owned) callback);
        });

        yield;
    }

We should use Idle.add instead of Threads.add, which is not equivalent, but we must not do this from other thread anyway.

[Corentin Noël (tintou)]

It is an old bug, I hope it doesn't happened anymore, if it does, reopen it.