invalid read after doing some uninstalls

[Sebastien Bacher]

Using the 17.10 version, after uninstall some snaps those errors were displayed in the valgrind log

==4467== Invalid read of size 8
==4467== at 0x52E824D: g_type_check_instance (gtype.c:4129)
==4467== by 0x52DAE62: g_signal_connect_data (gsignal.c:2483)
==4467== by 0x149A33: gs_installed_page_app_removed (gs-installed-page.c:118)
==4467== by 0x14EA2B: gs_page_app_removed_cb (gs-page.c:245)
==4467== by 0x58A5202: g_task_return_now (gtask.c:1145)
==4467== by 0x58A5238: complete_in_idle_cb (gtask.c:1159)
==4467== by 0x5550E24: g_main_dispatch (gmain.c:3148)
==4467== by 0x5550E24: g_main_context_dispatch (gmain.c:3813)
==4467== by 0x55511EF: g_main_context_iterate.isra.30 (gmain.c:3886)
==4467== by 0x555127B: g_main_context_iteration (gmain.c:3947)
==4467== by 0x58BAC4C: g_application_run (gapplication.c:2401)
==4467== by 0x12A117: main (gs-main.c:59)
==4467== Address 0x15f48dd0 is 544 bytes inside a block of size 600 free'd
==4467== at 0x4C30D3B: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==4467== by 0x52E6AE2: g_type_free_instance (gtype.c:1937)
==4467== by 0x136833: gs_app_row_unreveal (gs-app-row.c:508)
==4467== by 0x148948: gs_installed_page_unreveal_row (gs-installed-page.c:102)
==4467== by 0x149A33: gs_installed_page_app_removed (gs-installed-page.c:118)
==4467== by 0x14EA2B: gs_page_app_removed_cb (gs-page.c:245)
==4467== by 0x58A5202: g_task_return_now (gtask.c:1145)
==4467== by 0x58A5238: complete_in_idle_cb (gtask.c:1159)
==4467== by 0x5550E24: g_main_dispatch (gmain.c:3148)
==4467== by 0x5550E24: g_main_context_dispatch (gmain.c:3813)
==4467== by 0x55511EF: g_main_context_iterate.isra.30 (gmain.c:3886)
==4467== by 0x555127B: g_main_context_iteration (gmain.c:3947)
==4467== by 0x58BAC4C: g_application_run (gapplication.c:2401)
==4467== Block was alloc'd at
==4467== at 0x4C2FB0F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==4467== by 0x5556578: g_malloc (gmem.c:94)
==4467== by 0x556E0F5: g_slice_alloc (gslice.c:1025)
==4467== by 0x556E588: g_slice_alloc0 (gslice.c:1051)
==4467== by 0x52E67E5: g_type_create_instance (gtype.c:1839)
==4467== by 0x52C75E7: g_object_new_internal (gobject.c:1797)
==4467== by 0x52C8D84: g_object_new_with_properties (gobject.c:1965)
==4467== by 0x52C9800: g_object_new (gobject.c:1637)
==4467== by 0x136D3C: gs_app_row_new (gs-app-row.c:835)
==4467== by 0x148ADE: gs_installed_page_add_app (gs-installed-page.c:185)
==4467== by 0x1497A2: gs_installed_page_get_installed_cb (gs-installed-page.c:244)
==4467== by 0x58A5202: g_task_return_now (gtask.c:1145)

[Sebastien Bacher (seb128)]

Reported upstream as well on https://bugzilla.gnome.org/show_bug.cgi?id=789433