Processes randomly get stuck

Processes randomly get stuck

[Ismail Donmez]

Hi,

$ uname -a
CYGWIN_NT-10.0 ux31a 2.2.0(0.289/5/3) 2015-07-23 20:41 x86_64 Cygwin

For the last week or so ssh/zsh processes are randomly gets into defunct 
state, that is

$ cat /proc/7232/cmdline
<defunct>
$ cat /proc/7232/status
Name:   zsh
State:  S (sleeping)
Tgid:   7232
Pid:    7232
PPid:   5172
Uid:    197609 197609 197609 197609
Gid:    197609 197609 197609 197609
VmSize:     7556 kB
VmLck:         0 kB
VmRSS:     10860 kB
VmData:     2140 kB
VmStk:         0 kB
VmExe:         0 kB
VmLib:      4644 kB
SigPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 0000000000000000

Same happens with ssh, and after some time like 5 minutes or so it goes 
back to the normal state. I wonder if anyone has been experiencing 
something similar?




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Re: Processes randomly get stuck

[Corinna Vinschen]

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On Jul 26 12:56, Ismail Donmez wrote:
> Hi,
> 
> $ uname -a
> CYGWIN_NT-10.0 ux31a 2.2.0(0.289/5/3) 2015-07-23 20:41 x86_64 Cygwin
> 
> For the last week or so ssh/zsh processes are randomly gets into defunct 
> state, that is
> 
> $ cat /proc/7232/cmdline
> <defunct>
> $ cat /proc/7232/status
> Name:   zsh
> State:  S (sleeping)
> Tgid:   7232
> Pid:    7232
> PPid:   5172
> Uid:    197609 197609 197609 197609
> Gid:    197609 197609 197609 197609
> VmSize:     7556 kB
> VmLck:         0 kB
> VmRSS:     10860 kB
> VmData:     2140 kB
> VmStk:         0 kB
> VmExe:         0 kB
> VmLib:      4644 kB
> SigPnd: 0000000000000000
> SigBlk: 0000000000000000
> SigIgn: 0000000000000000
> 
> Same happens with ssh, and after some time like 5 minutes or so it goes 
> back to the normal state. I wonder if anyone has been experiencing 
> something similar?

There's no change in 2.2.0 which might explain this, but still, did
you try to downgrade to 2.1.0?


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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Re: Processes randomly get stuck

[Ismail Donmez]

Hi,

Corinna Vinschen writes:

> 
> On Jul 26 12:56, Ismail Donmez wrote:
> > Hi,
> > 
> > $ uname -a
> > CYGWIN_NT-10.0 ux31a 2.2.0(0.289/5/3) 2015-07-23 20:41 x86_64 Cygwin
> > 
> > For the last week or so ssh/zsh processes are randomly gets into 
defunct 
> > state, that is
> > 
> > $ cat /proc/7232/cmdline
> > <defunct>
> > $ cat /proc/7232/status
> > Name:   zsh
> > State:  S (sleeping)
> > Tgid:   7232
> > Pid:    7232
> > PPid:   5172
> > Uid:    197609 197609 197609 197609
> > Gid:    197609 197609 197609 197609
> > VmSize:     7556 kB
> > VmLck:         0 kB
> > VmRSS:     10860 kB
> > VmData:     2140 kB
> > VmStk:         0 kB
> > VmExe:         0 kB
> > VmLib:      4644 kB
> > SigPnd: 0000000000000000
> > SigBlk: 0000000000000000
> > SigIgn: 0000000000000000
> > 
> > Same happens with ssh, and after some time like 5 minutes or so it 
goes 
> > back to the normal state. I wonder if anyone has been experiencing 
> > something similar?
> 
> There's no change in 2.2.0 which might explain this, but still, did
> you try to downgrade to 2.1.0?

I tried to see the patterns of this problem before replying again. Because 
the bug randomly appears I can't conclude if 2.1.0 was any better (though 
I couldn't reproduce the problem with it.)

I have an idea why this might be happening and want to ask what happens 
each time one does read /proc/<pid>/cmdline, does the function 
_pinfo::commune_request called everytime, or just once?

This might explain some behaviour I am seeing because tmux is reading that 
file every 20 seconds or something like that.

Thanks!

ismail
 




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Re: Processes randomly get stuck

[Corinna Vinschen]

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On Aug 21 08:09, Ismail Donmez wrote:
> Hi,
> 
> Corinna Vinschen writes:
> 
> > 
> > On Jul 26 12:56, Ismail Donmez wrote:
> > > Hi,
> > > 
> > > $ uname -a
> > > CYGWIN_NT-10.0 ux31a 2.2.0(0.289/5/3) 2015-07-23 20:41 x86_64 Cygwin
> > > 
> > > For the last week or so ssh/zsh processes are randomly gets into 
> defunct 
> > > state, that is
> > > 
> > > $ cat /proc/7232/cmdline
> > > <defunct>
> > > $ cat /proc/7232/status
> > > Name:   zsh
> > > State:  S (sleeping)
> > > Tgid:   7232
> > > Pid:    7232
> > > PPid:   5172
> > > Uid:    197609 197609 197609 197609
> > > Gid:    197609 197609 197609 197609
> > > VmSize:     7556 kB
> > > VmLck:         0 kB
> > > VmRSS:     10860 kB
> > > VmData:     2140 kB
> > > VmStk:         0 kB
> > > VmExe:         0 kB
> > > VmLib:      4644 kB
> > > SigPnd: 0000000000000000
> > > SigBlk: 0000000000000000
> > > SigIgn: 0000000000000000
> > > 
> > > Same happens with ssh, and after some time like 5 minutes or so it 
> goes 
> > > back to the normal state. I wonder if anyone has been experiencing 
> > > something similar?
> > 
> > There's no change in 2.2.0 which might explain this, but still, did
> > you try to downgrade to 2.1.0?
> 
> I tried to see the patterns of this problem before replying again. Because 
> the bug randomly appears I can't conclude if 2.1.0 was any better (though 
> I couldn't reproduce the problem with it.)
> 
> I have an idea why this might be happening and want to ask what happens 
> each time one does read /proc/<pid>/cmdline, does the function 
> _pinfo::commune_request called everytime, or just once?

Every time.  There's no caching mechanism for data fetched from /proc
files and the command line is only available inside the process itself.

> This might explain some behaviour I am seeing because tmux is reading that 
> file every 20 seconds or something like that.

Oops.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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Re: Processes randomly get stuck

[Ismail Donmez]

Hi,

Corinna Vinschen:

> > This might explain some behaviour I am seeing because tmux is reading 
that 
> > file every 20 seconds or something like that.
> 
> Oops.

Well its even worse than that, its reading /proc/<pid>/cmdline twice every 
*second* , for now I'll disable this insane behaviour and see if things 
improve.





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Re: Processes randomly get stuck

[Corinna Vinschen]

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On Aug 21 08:49, Ismail Donmez wrote:
> Hi,
> 
> Corinna Vinschen:
> 
> > > This might explain some behaviour I am seeing because tmux is reading 
> that 
> > > file every 20 seconds or something like that.
> > 
> > Oops.
> 
> Well its even worse than that, its reading /proc/<pid>/cmdline twice every 
> *second* , for now I'll disable this insane behaviour and see if things 
> improve.

What on earth is it expecting?


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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Re: Processes randomly get stuck

[Ismail Donmez]

Corinna Vinschen writes:

> 
> On Aug 21 08:49, Ismail Donmez wrote:
> > Hi,
> > 
> > Corinna Vinschen:
> > 
> > > > This might explain some behaviour I am seeing because tmux is 
reading 
> > that 
> > > > file every 20 seconds or something like that.
> > > 
> > > Oops.
> > 
> > Well its even worse than that, its reading /proc/≤pid>/cmdline twice 
every 
> > *second* , for now I'll disable this insane behaviour and see if 
things 
> > improve.
> 
> What on earth is it expecting?

The idea is it updates the window title as needed, so you can zsh on tmux 
and the title is "zsh" and then you fire up vim and the title changes to 
"vim" etc.

Apparently this is less of a problem on Linux because I never even noticed 
it was doing this.

ismail