Re: [PATCH] fix for ssh zombies introduced with r35533

["Hyrum K. Wright" <hy...@mail.utexas.edu>]

Kyle,
Just letting you know this hasn't fallen on deaf ears.  It's on my  
stack somewhere. :)

-Hyrum

On Mar 28, 2009, at 6:04 PM, Kyle McKay wrote:

> [[[
> Fix ssh zombie problem introduced with revision 35533
>
> * subversion/libsvn_ra_svn/client.c
>  (make_tunnel): Fully detach tunnel process to avoid having it
>                 receive signals while restoring the original
>                 apr_pool_note_subprocess to avoid creating zombies.
> ]]]
>
> As detailed in this thread:
>
> http://subversion.tigris.org/ds/viewMessage.do?dsForumId=462&dsMessageId=1445592
>
> regarding the change introduced into client.c by revision 35533:
>
> http://svn.collab.net/viewvc/svn?view=revision&revision=35533
>
> On Mar 27, 2009, at 09:51, Hyrum K. Wright wrote:
>> The case which drove r35533 was a user who uses ssh connection  
>> pooling for svn connections.
>
> Change r35533 removed the call to to apr_pool_note_subprocess  
> meaning that Subversion never reaps any of its children.  This may  
> be okay for a short-lived process, but is not okay for a long-lived  
> process such as a GUI tool that has linked with the Subversion  
> library.
>
> If the GUI tool runs long enough, it can create so many un-reaped  
> zombie processes that system resources are exhausted and it becomes  
> impossible to spawn any new processes.
>
> The attached patch restores the original call to  
> apr_pool_note_subprocess thus guaranteeing no zombies are ever  
> created.  It also arranges for the tunnel process to become detached  
> so that it can "die in piece, in its own time, on its own terms" as  
> the log comment for revision 35533 mentions, but without causing  
> zombie processes to be created.
>
> This change retains full compatibility with ssh connection pooling  
> while eliminating the zombie problem.  See issue #2580 for the  
> original impetus for the change made in revision 35533.
>
> http://subversion.tigris.org/issues/show_bug.cgi?id=2580
>
> Kyle
>
> <client.c-patch>

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