https://bugs.kde.org/show_bug.cgi?id=380495
Bug ID: 380495
Summary: Freezes during login process
Product: plasmashell
Version: 5.8.6
Platform: Debian testing
OS: Linux
Status: UNCONFIRMED
Severity: grave
Priority: NOR
Component: Multi-screen support
Assignee: aleix...@kde.org
Reporter: iwama...@nigauri.org
CC: plasma-b...@kde.org
Target Milestone: 1.0
Created attachment 105862
--> https://bugs.kde.org/attachment.cgi?id=105862&action=edit
a patch
Login processing stops with ksplashqml.
This causes problems in the uim Japanese input environment of Debian stretch
(Debian 9).
When Mr.Yoshino investigated this problem, he and I thought that this is
ksplashqml's problem, not uim and other software.
An upstream commit
https://cgit.kde.org/plasma-workspace.git/commit/?id=56d2c15b9acb9c4b57398b281685807c3191f622
has caused this problem.
x-session-manag,133,kdetest /usr/bin/x-session-manager
├─(ksplashqml,232)
├─ssh-agent,191 /usr/bin/im-launch x-session-manager
├─uim-toolbar,220
│ ├─{llvmpipe-0},235
│ ├─{llvmpipe-1},236
│ ├─{llvmpipe-2},237
│ └─{llvmpipe-3},238
└─uim-xim,219
ksplashqml,233,kdetest Breeze --pid
├─mozc_server,239
│ ├─{IPCServer},244
│ ├─{QueueTimer},240
│ ├─{QueueTimer},243
│ └─{WatchDog},242
├─uim-candwin-qt5,245 -v
│ ├─{QDBusConnection},249
│ └─{QXcbEventReader},248
├─{QDBusConnection},255
├─{QQmlThread},254
├─{QXcbEventReader},234
├─{llvmpipe-0},250
├─{llvmpipe-1},251
├─{llvmpipe-2},252
└─{llvmpipe-3},253
# strace -f -p 133
strace: Process 133 attached
read(3, ^Cstrace: Process 133 detached
<detached ...>
It looks like the parent process (133), x-session-manager (startkde
script), is waiting for the stdout of the ksplashqml process (232),
but which is now defunct. Its child process(es) may be writing to the
same fd.
# ls -l /proc/133/fd/3
lr-x------ 1 kdetest kdetest 64 May 31 05:13 /proc/133/fd/3 -> pipe:[88694]
The direct child of the ksplashqml process (233), the splash screen daemon,
closes the file descriptor at ksplash/ksplashqml/main.cpp:97.
# ls -l /proc/233/fd/1
ls: cannot access '/proc/233/fd/1': No such file or directory
One of the children of the process (239), mozc_server, is holding the fd:
# ls -l /proc/239/fd/1
l-wx------ 1 kdetest kdetest 64 May 31 05:14 /proc/239/fd/1 -> pipe:[88694]
So the startkde process has finished reading the pid number string from
the now-defunct process, but is still waiting for another write(s) until
the (shared) fd has been closed.
This mozc_server process has been started during uim-qt5
(a QPlatformInputContext) startup in the SplashApp
initialization phase at ksplash/ksplashqml/main.cpp:92.
Due to the upstream commit the splash screen daemon does not close file
descriptors before the SplashApp initialization, thus its subprocess
shares the fds.
The commit log states Wayland initialization of this daemon needs the
channels. While it may require open file descriptors 0, 1 or 2,
no one should expect the process to talk to the parent through the
descriptors, since the splash screen is a daemon.
An attached patch reverts the commit and redirects the file descriptors
to /dev/null.
MR.Yoshino created a patch which revise this problem.
Could you check this patch?
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