[Bug 1852016] Re: Applications delayed on launch

[Digulla-hepe]

Just a heads up: I'm seeing exactly the same behavior on OpenSUSE LEAP
15.2

This happens with Xfce4 desktop.

It seems to be a rare bug; no one has hard about this when I asked on
the mailing list.

I did some debugging of keepassxc (since it's a relatively small app).

Installed some debug packages, then "gdb keypassxc", wait 5 seconds
until it stops printing "[New Thread 0x7fffe945b700 (LWP 18090)]", then
Ctrl+C to get the stack traces.

"info threads" to see which threads there are. "thread " + id to switch
between them.

The app hangs for 25 seconds when I try to start it which matches this
timeout:

__GI___poll (fds=0x555555f994d0, nfds=1, timeout=25000) at
../sysdeps/unix/sysv/linux/poll.c:29

Googling returned this analysis:

https://freefilesync.org/forum/viewtopic.php?t=6704

The stack traces look very similar: Threads hanging in __lll_lock_wait
and __GI___poll called from ibus_bus_new_async_client and
g_simple_async_result_get_type respectively.

In the mean time, I've found more apps with the same symptom:

- qmmp

- qtconfig ("Qt 4 settings" in the Xfce settings dialog.)

I'm wondering about this line in the stack trace:

/usr/lib64/qt5/plugins/styles/libqgtk2style.so

Maybe there is a bug in the Qt style which I'm using.

Stack frame 45 says style is
"QGtk2Theme::themeHint(QPlatformTheme::ThemeHint)
const::{lambda()#1}::operator()() const::qstring_literal"

which would match the setting in the "Qt 4 settings" dialog but I'm
using Qt5. Or is the dialog for both?

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https://bugs.launchpad.net/bugs/1852016

Title:
  Applications delayed on launch

Status in dbus package in Ubuntu:
  Confirmed

Bug description:
  Hello,

  i am unsure if this is really a problem with dbus but my first
  research showed it could be related to dbus.

  1.) 
  No LSB modules are available.
  Distributor ID:	Ubuntu
  Description:	Ubuntu 19.10
  Release:	19.10
  Codename:	eoan

  Ubuntu Budgie on T460 with 256GB SSD and 16GB RAM

  2.)
  dbus:
    Installed: 1.12.14-1ubuntu2
    Candidate: 1.12.14-1ubuntu2
    Version table:
   *** 1.12.14-1ubuntu2 500
          500 http://de.archive.ubuntu.com/ubuntu eoan/main amd64 Packages
          100 /var/lib/dpkg/status

  3.) I've expected just "normal" loading applications

  4.) Some applications are delayed at startup. The application will
  take around 30s to launch, but afterwards it just runs fine. Affected
  application I found so far are KeepassXC, Filezilla and OnlyOffice
  Desktop-Editor. From strace I saw this applications are stopping (for
  about 20-30s) at this point:

  connect(12, {sa_family=AF_UNIX, sun_path="/run/user/1000/bus"}, 110) = 0
  getpid()                                = 8165
  geteuid()                               = 1000
  getegid()                               = 1000
  getpid()                                = 8165
  geteuid()                               = 1000
  getegid()                               = 1000
  sendmsg(12, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="\0", iov_len=1}], msg_iovlen=1, msg_control=[{cmsg_len=28, cmsg_level=SOL_SOCKET, cmsg_type=SCM_CREDENTIALS, cmsg_data={pid=8165, uid=1000, gid=1000}}], msg_controllen=32, msg_flags=0}, MSG_NOSIGNAL) = 1
  sendto(12, "AUTH\r\n", 6, MSG_NOSIGNAL, NULL, 0) = 6
  recvfrom(12, "REJECTED EXTERNAL\r\n", 4096, 0, NULL, NULL) = 19
  sendto(12, "AUTH EXTERNAL 31303030\r\n", 24, MSG_NOSIGNAL, NULL, 0) = 24
  recvfrom(12, "OK 7f079149c4e5e774135107445dc85"..., 4096, 0, NULL, NULL) = 37
  sendto(12, "NEGOTIATE_UNIX_FD\r\n", 19, MSG_NOSIGNAL, NULL, 0) = 19
  recvfrom(12, "AGREE_UNIX_FD\r\n", 4096, 0, NULL, NULL) = 15
  sendto(12, "BEGIN\r\n", 7, MSG_NOSIGNAL, NULL, 0) = 7
  write(15, "\1\0\0\0\0\0\0\0", 8)        = 8
  eventfd2(0, EFD_CLOEXEC|EFD_NONBLOCK)   = 14
  write(14, "\1\0\0\0\0\0\0\0", 8)        = 8
  write(15, "\1\0\0\0\0\0\0\0", 8)        = 8
  poll([{fd=14, events=POLLIN}], 1, 25000) = 1 ([{fd=14, revents=POLLIN}])
  read(14, "\1\0\0\0\0\0\0\0", 16)        = 8
  poll([{fd=14, events=POLLIN}], 1, 25000

  
  During my first research I found this following to topics related to the issue:
  https://askubuntu.com/questions/1184774/some-applications-on-ubuntu-19-10-very-slow-to-start

  This Stackoverflow topic links to the archlinux forum:
  https://bbs.archlinux.org/viewtopic.php?id=230036

  I can confirm that running the delayed applications with "dbus-launch
  --exit-with-session application" or by running it as root they are all
  starting without any delay.

  Thanks for your help! Let me know if you need any further information.

  Best Regards,
  Sebastian

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