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Date: Sun, 12 Jul 2015 10:51:57 -0700
Message-ID: <CAG6CVpVWCxfvtnt8vQ4SiSBa=n832-gTQ7vAY8AipgQVbjueXQ@mail.gmail.com>
Subject: Re: unp gc vs socket close/shutdown race
From: Conrad Meyer <cse.cem@gmail.com>
To: freebsd-current@freebsd.org
Cc: Mateusz Guzik <mjguzik@gmail.com>
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Hi all,

(Sorry In-Reply-To is wrong; gmail isn't the most flexible MUA and I
was not subscribed to FreeBSD-Current until today.)

I have a slightly cleaned up version of this patch in phabricator at
https://reviews.freebsd.org/D3044 . My mentor thinks it looks ok, but
we would appreciate any feedback y'all have. The PR is here:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=194264 .

Primary changes from MJG's patch:

* Rather than adding PR_DISPOSE2 flag, we just change dom_dispose KPI.
Unix local domain is the only in-tree consumer.

* Use unp_gcflag IGNORED flag to only skip scanning RIGHTS on a socket
during GC mark phase. Unix sockets may refer to other sockets in the
graph while being half shutdown (shutdown(SHUT_RD)), they just won't
have valid RIGHTS.

Thanks,
Conrad