Date: Mon, 06 Oct 2014 11:37:32 -0400 From: John Baldwin <jhb@freebsd.org> To: Mateusz Guzik <mjg@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r272596 - head/sys/fs/devfs Message-ID: <13670379.opPJl0kA6Z@ralph.baldwin.cx> In-Reply-To: <201410060620.s966Kaqt078736@svn.freebsd.org> References: <201410060620.s966Kaqt078736@svn.freebsd.org>
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On Monday, October 06, 2014 06:20:36 AM Mateusz Guzik wrote: > Author: mjg > Date: Mon Oct 6 06:20:35 2014 > New Revision: 272596 > URL: https://svnweb.freebsd.org/changeset/base/272596 > > Log: > devfs: don't take proctree_lock unconditionally in devfs_close > > MFC after: 1 week Just for my sanity: What keeps td->td_proc->p_session static in this case so that it is safe to dereference it? Specifically, if you are preempted after reading p_session but before you then read s_ttyvp, what prevents a race with another thread changing the session of td->td_proc? -- John Baldwin
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