[Bug 1890313] Re: libxmlb/0.1.15-2 autopkgtest fails or is flaky
Iain Lane
1890313 at bugs.launchpad.net
Mon Jan 25 15:55:00 UTC 2021
** Description changed:
+ [ Description ]
+
https://autopkgtest.ubuntu.com/packages/libx/libxmlb/groovy/amd64
https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac
/autopkgtest-
groovy/groovy/amd64/libx/libxmlb/20200803_212158_ebe4f@/log.gz :
...
(/usr/libexec/installed-tests/libxmlb/xb-self-test:1066): XbSilo-DEBUG: 21:16:46.741: /tmp/temp.xml changed, invalidating
Executing: libxmlb/libxmlb.test
Executing: libxmlb/libxmlb.test
...
Executing: libxmlb/libxmlb.test
Executing: libxmlb/libxmlb.test
Executing: libxmlb/libxmlb.test
Executing: libxmlb/libxmlb.test
Test timed out after 300 seconds
Executing: libxmlb/libxmlb.test
FAIL: libxmlb/libxmlb.test (Child process killed by signal 9)
SUMMARY: total=1; passed=0; skipped=0; failed=1; user=0.0s; system=0.0s; maxrss=5900
FAIL: libxmlb/libxmlb.test (Child process killed by signal 9)
...
+
+ The backtrace while the test is hanging looks like:
+
+ (gdb) bt
+ #0 syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
+ #1 0x00007fc9150d57cc in g_mutex_lock_slowpath (mutex=mutex at entry=0x7fc9153a0318 <g.inotify_lock_lock>)
+ at ../../../glib/gthread-posix.c:1458
+ #2 0x00007fc9150d6256 in g_mutex_lock (mutex=mutex at entry=0x7fc9153a0318 <g.inotify_lock_lock>) at ../../../glib/gthread-posix.c:1482
+ #3 0x00007fc915309de4 in _ih_sub_cancel (sub=0x55a566f5be10) at ../../../gio/inotify/inotify-helper.c:121
+ #4 0x00007fc91530a06e in g_inotify_file_monitor_cancel (monitor=0x55a566f501a0) at ../../../gio/inotify/ginotifyfilemonitor.c:75
+ #5 0x00007fc91523680b in g_file_monitor_cancel (monitor=0x55a566f501a0) at ../../../gio/gfilemonitor.c:241
+ #6 g_file_monitor_cancel (monitor=0x55a566f501a0) at ../../../gio/gfilemonitor.c:235
+ #7 0x00007fc915236890 in g_file_monitor_dispose (object=0x55a566f501a0) at ../../../gio/gfilemonitor.c:123
+ #8 0x00007fc9152fe8b3 in g_local_file_monitor_dispose (object=0x55a566f501a0) at ../../../gio/glocalfilemonitor.c:814
+ #9 0x00007fc915179c93 in g_object_unref (_object=<optimized out>) at ../../../gobject/gobject.c:3461
+ #10 g_object_unref (_object=0x55a566f501a0) at ../../../gobject/gobject.c:3391
+ #11 0x000055a5666dce9d in xb_silo_file_monitor_item_free (item=0x55a566f53810) at ../src/xb-silo.c:1220
+ #12 0x00007fc915075172 in g_hash_table_remove_all_nodes (hash_table=hash_table at entry=0x55a566f62b60, notify=notify at entry=1,
+ destruction=destruction at entry=1) at ../../../glib/ghash.c:706
+ #13 0x00007fc915076533 in g_hash_table_remove_all_nodes (destruction=1, notify=1, hash_table=0x55a566f62b60)
+ at ../../../glib/ghash.c:1461
+ #14 g_hash_table_unref (hash_table=0x55a566f62b60) at ../../../glib/ghash.c:1461
+ #15 0x000055a5666dd445 in xb_silo_finalize (obj=0x55a566f47a00) at ../src/xb-silo.c:1320
+ #16 0x00007fc915179d0e in g_object_unref (_object=<optimized out>) at ../../../gobject/gobject.c:3499
+ #17 g_object_unref (_object=0x55a566f47a00) at ../../../gobject/gobject.c:3391
+ #18 0x000055a5666c4864 in xb_builder_finalize (obj=0x55a566f46da0) at ../src/xb-builder.c:1027
+ #19 0x00007fc915179d0e in g_object_unref (_object=<optimized out>) at ../../../gobject/gobject.c:3499
+ #20 g_object_unref (_object=0x55a566f46da0) at ../../../gobject/gobject.c:3391
+ #21 0x000055a5666db999 in glib_autoptr_clear_GObject (_ptr=0x55a566f46da0) at /usr/include/glib-2.0/gobject/gobject-autocleanups.h:27
+ #22 glib_autoptr_clear_XbBuilder (_ptr=0x55a566f46da0) at ../src/xb-builder.h:20
+ #23 glib_autoptr_cleanup_XbBuilder (_ptr=<synthetic pointer>) at ../src/xb-builder.h:20
+ #24 xb_builder_ensure_watch_source_func () at ../src/xb-self-test.c:501
+ #25 0x00007fc9150b13ce in test_case_run (tc=0x55a566f43b00) at ../../../glib/gtestutils.c:2633
+ #26 g_test_run_suite_internal (suite=suite at entry=0x55a566f42440, path=path at entry=0x0) at ../../../glib/gtestutils.c:2721
+ #27 0x00007fc9150b1174 in g_test_run_suite_internal (suite=suite at entry=0x55a566f42420, path=path at entry=0x0)
+ at ../../../glib/gtestutils.c:2733
+ #28 0x00007fc9150b18ba in g_test_run_suite (suite=0x55a566f42420) at ../../../glib/gtestutils.c:2808
+ #29 0x00007fc9150b18d5 in g_test_run () at ../../../glib/gtestutils.c:2043
+ #30 0x000055a5666c38bb in main (argc=<optimized out>, argv=<optimized out>) at ../src/xb-self-test.c:2423
+ (gdb)
+
+ [ Fix ]
+
+ This is a hang when disposing the GFileMonitor.
+
+ See https://gitlab.gnome.org/GNOME/glib/-/issues/1941 for more details.
+
+ The fix is to explicitly cancel the GFileMonitor when when unreffing it.
+
+ [ QA ]
+
+ We don't have a testcase for the bug in real usage. It's quite easy to
+ check in autopkgtest though. Check the autopkgtests stop being
+ flaky/racy with the new version.
+
+ [ What could go wrong ]
+
+ We're cancelling the file monitor explicitly now. Previously this was
+ happening internally. This is a pattern used by other glib-using
+ projects, but if it's bad then it may be that something goes wrong with
+ the file monitor.
+
+ [ Other information ]
+
+ I'll stage this following
+ https://wiki.ubuntu.com/StableReleaseUpdates#Staging_an_upload.
+
+ Although this is a bug that could arguably affect users too (the fix is
+ not limited to test code). So it may fix a real hang bug which we just
+ didn't notice - or get reported - yet. I think it *could* be released to
+ users.
** Also affects: libxmlb (Ubuntu Groovy)
Importance: Undecided
Status: New
** Also affects: libxmlb (Ubuntu Focal)
Importance: Undecided
Status: New
** Changed in: libxmlb (Ubuntu)
Assignee: (unassigned) => Iain Lane (laney)
** Changed in: libxmlb (Ubuntu Focal)
Assignee: (unassigned) => Iain Lane (laney)
** Changed in: libxmlb (Ubuntu Groovy)
Assignee: (unassigned) => Iain Lane (laney)
** Changed in: libxmlb (Ubuntu)
Status: New => In Progress
** Changed in: libxmlb (Ubuntu Focal)
Status: New => In Progress
** Changed in: libxmlb (Ubuntu Groovy)
Status: New => In Progress
** Tags added: block-proposed-focal block-proposed-groovy
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https://bugs.launchpad.net/bugs/1890313
Title:
libxmlb/0.1.15-2 autopkgtest fails or is flaky
Status in libxmlb package in Ubuntu:
In Progress
Status in libxmlb source package in Focal:
In Progress
Status in libxmlb source package in Groovy:
In Progress
Bug description:
[ Description ]
https://autopkgtest.ubuntu.com/packages/libx/libxmlb/groovy/amd64
https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac
/autopkgtest-
groovy/groovy/amd64/libx/libxmlb/20200803_212158_ebe4f@/log.gz :
...
(/usr/libexec/installed-tests/libxmlb/xb-self-test:1066): XbSilo-DEBUG: 21:16:46.741: /tmp/temp.xml changed, invalidating
Executing: libxmlb/libxmlb.test
Executing: libxmlb/libxmlb.test
...
Executing: libxmlb/libxmlb.test
Executing: libxmlb/libxmlb.test
Executing: libxmlb/libxmlb.test
Executing: libxmlb/libxmlb.test
Test timed out after 300 seconds
Executing: libxmlb/libxmlb.test
FAIL: libxmlb/libxmlb.test (Child process killed by signal 9)
SUMMARY: total=1; passed=0; skipped=0; failed=1; user=0.0s; system=0.0s; maxrss=5900
FAIL: libxmlb/libxmlb.test (Child process killed by signal 9)
...
The backtrace while the test is hanging looks like:
(gdb) bt
#0 syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
#1 0x00007fc9150d57cc in g_mutex_lock_slowpath (mutex=mutex at entry=0x7fc9153a0318 <g.inotify_lock_lock>)
at ../../../glib/gthread-posix.c:1458
#2 0x00007fc9150d6256 in g_mutex_lock (mutex=mutex at entry=0x7fc9153a0318 <g.inotify_lock_lock>) at ../../../glib/gthread-posix.c:1482
#3 0x00007fc915309de4 in _ih_sub_cancel (sub=0x55a566f5be10) at ../../../gio/inotify/inotify-helper.c:121
#4 0x00007fc91530a06e in g_inotify_file_monitor_cancel (monitor=0x55a566f501a0) at ../../../gio/inotify/ginotifyfilemonitor.c:75
#5 0x00007fc91523680b in g_file_monitor_cancel (monitor=0x55a566f501a0) at ../../../gio/gfilemonitor.c:241
#6 g_file_monitor_cancel (monitor=0x55a566f501a0) at ../../../gio/gfilemonitor.c:235
#7 0x00007fc915236890 in g_file_monitor_dispose (object=0x55a566f501a0) at ../../../gio/gfilemonitor.c:123
#8 0x00007fc9152fe8b3 in g_local_file_monitor_dispose (object=0x55a566f501a0) at ../../../gio/glocalfilemonitor.c:814
#9 0x00007fc915179c93 in g_object_unref (_object=<optimized out>) at ../../../gobject/gobject.c:3461
#10 g_object_unref (_object=0x55a566f501a0) at ../../../gobject/gobject.c:3391
#11 0x000055a5666dce9d in xb_silo_file_monitor_item_free (item=0x55a566f53810) at ../src/xb-silo.c:1220
#12 0x00007fc915075172 in g_hash_table_remove_all_nodes (hash_table=hash_table at entry=0x55a566f62b60, notify=notify at entry=1,
destruction=destruction at entry=1) at ../../../glib/ghash.c:706
#13 0x00007fc915076533 in g_hash_table_remove_all_nodes (destruction=1, notify=1, hash_table=0x55a566f62b60)
at ../../../glib/ghash.c:1461
#14 g_hash_table_unref (hash_table=0x55a566f62b60) at ../../../glib/ghash.c:1461
#15 0x000055a5666dd445 in xb_silo_finalize (obj=0x55a566f47a00) at ../src/xb-silo.c:1320
#16 0x00007fc915179d0e in g_object_unref (_object=<optimized out>) at ../../../gobject/gobject.c:3499
#17 g_object_unref (_object=0x55a566f47a00) at ../../../gobject/gobject.c:3391
#18 0x000055a5666c4864 in xb_builder_finalize (obj=0x55a566f46da0) at ../src/xb-builder.c:1027
#19 0x00007fc915179d0e in g_object_unref (_object=<optimized out>) at ../../../gobject/gobject.c:3499
#20 g_object_unref (_object=0x55a566f46da0) at ../../../gobject/gobject.c:3391
#21 0x000055a5666db999 in glib_autoptr_clear_GObject (_ptr=0x55a566f46da0) at /usr/include/glib-2.0/gobject/gobject-autocleanups.h:27
#22 glib_autoptr_clear_XbBuilder (_ptr=0x55a566f46da0) at ../src/xb-builder.h:20
#23 glib_autoptr_cleanup_XbBuilder (_ptr=<synthetic pointer>) at ../src/xb-builder.h:20
#24 xb_builder_ensure_watch_source_func () at ../src/xb-self-test.c:501
#25 0x00007fc9150b13ce in test_case_run (tc=0x55a566f43b00) at ../../../glib/gtestutils.c:2633
#26 g_test_run_suite_internal (suite=suite at entry=0x55a566f42440, path=path at entry=0x0) at ../../../glib/gtestutils.c:2721
#27 0x00007fc9150b1174 in g_test_run_suite_internal (suite=suite at entry=0x55a566f42420, path=path at entry=0x0)
at ../../../glib/gtestutils.c:2733
#28 0x00007fc9150b18ba in g_test_run_suite (suite=0x55a566f42420) at ../../../glib/gtestutils.c:2808
#29 0x00007fc9150b18d5 in g_test_run () at ../../../glib/gtestutils.c:2043
#30 0x000055a5666c38bb in main (argc=<optimized out>, argv=<optimized out>) at ../src/xb-self-test.c:2423
(gdb)
[ Fix ]
This is a hang when disposing the GFileMonitor.
See https://gitlab.gnome.org/GNOME/glib/-/issues/1941 for more
details.
The fix is to explicitly cancel the GFileMonitor when when unreffing
it.
[ QA ]
We don't have a testcase for the bug in real usage. It's quite easy to
check in autopkgtest though. Check the autopkgtests stop being
flaky/racy with the new version.
[ What could go wrong ]
We're cancelling the file monitor explicitly now. Previously this was
happening internally. This is a pattern used by other glib-using
projects, but if it's bad then it may be that something goes wrong
with the file monitor.
[ Other information ]
I'll stage this following
https://wiki.ubuntu.com/StableReleaseUpdates#Staging_an_upload.
Although this is a bug that could arguably affect users too (the fix
is not limited to test code). So it may fix a real hang bug which we
just didn't notice - or get reported - yet. I think it *could* be
released to users.
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