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From: Steve Wise <swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>
To: Roland Dreier <roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: linux-rdma <linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: ibv_fork_init() question
Date: Mon, 27 Feb 2012 13:54:53 -0600	[thread overview]
Message-ID: <4F4BDF8D.7070902@opengridcomputing.com> (raw)

Hey Roland,

I'm experimenting with doing RDMA operations from a child process and I have a question.  My application calls 
ibv_fork_init() at startup (first thing in main())  and it succeeds, and I see, for instance, that libibverbs has 
initialized mm_root.  Next my application registers page-aligned memory that is 8KB in size.  The memory was allocated 
with memalign().  Then the app sets up a connection to an RDMA peer.  Next the application calls fork().  The parent 
does a wait() and the child does an rdma read operation into this registered memory from a valid mr of the peer.  The 
read succeeds from the rdma device perspective.  But when the child process tries to read the memory (to verify the rdma 
operation worked), I get a seg fault.

Q: Am I doing something incorrect here?  I can't find much documentation on how this all should work.

Thanks!

Steve.


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             reply	other threads:[~2012-02-27 19:54 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-27 19:54 Steve Wise [this message]
     [not found] ` <4F4BDF8D.7070902-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>
2012-02-27 19:58   ` ibv_fork_init() question Roland Dreier

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