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From: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org
Cc: dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
	cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Bug in cgroup_do_mount()?
Date: Tue, 13 Jun 2017 15:27:27 +0100	[thread overview]
Message-ID: <25030.1497364047@warthog.procyon.org.uk> (raw)

I'm having a go at converting cgroups to use my fs_context stuff, and I've
spotted a potential bug in the existing code.  In cgroup_do_mount(), there is
the following snippet:

		mutex_lock(&cgroup_mutex);
		spin_lock_irq(&css_set_lock);

		cgrp = cset_cgroup_from_root(ns->root_cset, root);

		spin_unlock_irq(&css_set_lock);
		mutex_unlock(&cgroup_mutex);

		nsdentry = kernfs_node_dentry(cgrp->kn, dentry->d_sb);

Given that locks must be taken to call cset_cgroup_from_root(), is the value
of cgrp trustworthy once the locks are dropped?

David

             reply	other threads:[~2017-06-13 14:27 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-13 14:27 David Howells [this message]
     [not found] ` <25030.1497364047-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org>
2017-06-13 15:11   ` Bug in cgroup_do_mount()? Tejun Heo

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