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Issue 821543 link

Starred by 2 users

Issue metadata

Status: WontFix
Owner: ----
Closed: May 2018
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Linux
Pri: 3
Type: Bug

Blocking:
issue 813444
issue 814264
issue 818439



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Some processes are incorrectly named TaskSchedulerSi on Linux

Project Member Reported by gab@chromium.org, Mar 13 2018

Issue description

Reported by hubbe@ https://bugs.chromium.org/p/chromium/issues/detail?id=817314#c33 :

"""
Every 11 seconds, my Chrome starts a process called TaskSchedulerSi

I used the following command:

  while : ; do ps -fe | egrep 'Tas[k]Scheduler' ; done

The chrome task manager calls this process "Utility: Video Capture Service".
Apparently I'm not the only one noticing this process:
https://productforums.google.com/forum/#!topic/chrome/IjeicWOeYlo
"""

I suspect this is caused by platform_thread_linux.cc:PlatformThread::SetName() having an undesired side-effect of setting the process name (and TaskSchedulerSingleThreadWorkers happen to be hitting it when naming their thread).
 

Comment 1 by gab@chromium.org, Mar 13 2018

Blocking: 818439

Comment 2 by olka@chromium.org, Mar 14 2018

Cc: chfremer@chromium.org

Comment 3 by gab@chromium.org, Mar 14 2018

Cc: robliao@chromium.org
From robliao@ offline:

"""
My guess is a config issue. This is what I get:
   PID    TID   TGID COMMAND
202027 202027 202027 chrome
202027 202028 202027 sandbox_ipc_thr
202027 202043 202027 chrome
202027 202044 202027 gmain
202027 202045 202027 gdbus
202027 202046 202027 Chrome_IOThread
202027 202047 202027 NetworkChangeNo
202027 202048 202027 inotify_reader
202027 202049 202027 D-Bus thread
202027 202050 202027 CrShutdownDetec
202027 202051 202027 dconf worker
202027 202052 202027 TaskSchedulerSe
202027 202053 202027 TaskSchedulerBa
202027 202054 202027 TaskSchedulerBa
202027 202055 202027 TaskSchedulerBa
202027 202057 202027 TaskSchedulerFo
202027 202058 202027 TaskSchedulerFo
202027 202059 202027 TaskSchedulerFo
Without the tgid's set correctly, we don't know if the single thread task runner threads are associated with the same process or different processes
"""

platform_thread_linux.cc's PlatformThread::SetName() already skips setting the name if tid==pid (to avoid specifically this issue of setting the thread name altering the process name).

Our guess is therefore that in some configs the TGID (thread group IDs) aren't set properly which results in it looking like a "process" (in POSIX, AFAIU, processes and threads are equivalent -- threads are merely groups of threads when TGIDs are set properly).

Comment 4 by gab@chromium.org, Mar 21 2018

Blocking: 814264

Comment 5 by gab@chromium.org, Mar 21 2018

Blocking: 813444

Comment 6 by gab@chromium.org, May 3 2018

Components: Internals>Core
Status: WontFix (was: Untriaged)
From #3 it seems like Chrome is setting TGID properly, maybe some versions of Linux prevent this from being done correctly but I don't know that Chrome can do anything about it... I can't repro.

Not sure what "Utility: Video Capture Service" is doing differently (maybe sandboxing and forking have something to do with this result...).

I also can't find this process anymore in the source code... please re-open if more information arises, for now this is not actionable.

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