Re: [PATCH RFC] fork: remove cygpid.N sharedmem on fork failure

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Jun  5 15:05, Michael Haubenwallner wrote:
> Hi,
> 
> I'm using attached patch for a while now, and orphan cygpid.N shared memory
> instances are gone for otherwise completely unknown windows process ids.
> 
> However, I do see defunct processes now which's PPID does not exist (any more),
> causing the same trouble because their windows process handle is closed but
> their cygpid.N shmem handle is not.
> 
> For example, there is no PID 1768 anywhere, although it is the parent of both
> the <defunct> processes:
> $ ps -e
>       PID    PPID    PGID     WINPID   TTY         UID    STIME COMMAND
>      2416       1    1496       2416  ?         197610   May 25 /usr/bin/python2.7
>       560       1     560        560  ?         197613   May 25 /usr/bin/cygrunsrv
>      2348       1    2348       2348  ?         197612   May 25 /usr/bin/cygrunsrv
>      1132       1    1132       1132  ?         197612   May 16 /usr/bin/cygrunsrv
>       440    2028     440        740  pty0      197609   May 29 /tools/haubi/gentoo/test/usr/bin/bash
>      3664    1768    3612       3664  ?         197610 12:25:01 /usr/bin/python2.7 <defunct>
>      2852    2704    2852       2364  ?         197612   May 25 /usr/sbin/sshd
>      2268     560    2268       2128  ?         197613   May 25 /usr/libexec/sendmail
>      2968    1768    3612       1500  ?         197610 12:25:01 /usr/bin/tail <defunct>
> S    2832     512    2832       2312  pty0      197609 10:57:51 /usr/bin/vim
>      2028    2852    2028       2000  pty0      197609   May 25 /usr/bin/bash
>      1164    1132    1164       1256  ?         197612   May 16 /usr/sbin/cron
>       512     440     512       1544  pty0      197609   May 29 /tools/haubi/gentoo/test/usr/bin/bash
>      3264     512    3264       1488  pty0      197609 12:43:35 /usr/bin/ps
>      2704    2348    2704       2856  ?         197612   May 25 /usr/sbin/sshd
> 
> That missing 1768 process for sure was started as (grand) children of 2416.
> 
> Problem is again that another fork'ed child processes with PID 1768, 2968, 3612
> and probably others fail to initialize.
> 
> But I have no idea whether attached patch is causing or uncovering this issue...
> 
> Any idea?

Not really.  Processes are kept around after exec to keep the PID
blocked.  Perhaps your patch is breaking an assumption there.
I wonder why you have a problem with failing forks in the first
place...?


Corinna

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

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