Messages in this thread | | | Date | Mon, 13 Feb 2017 10:22:22 -0800 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH] kernfs: fix locking around kernfs_ops->release() callback |
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On Mon, Feb 13, 2017 at 09:57:25AM -0800, Tony Lindgren wrote: > * Tejun Heo <tj@kernel.org> [170211 12:34]: > > The release callback may be called from two places - file release > > operation and kernfs open file draining. kernfs_open_file->mutex is > > used to synchronize the two callsites. This unfortunately leads to > > possible circular locking because of->mutex is used to protect the > > usual kernfs operations which may use locking constructs which are > > held while removing and thus draining kernfs files. > > > > @of->mutex is for synchronizing concurrent kernfs access operations > > and all we need here is synchronization between the releaes and drain > > paths. As the drain path has to grab kernfs_open_file_mutex anyway, > > let's use the mutex to synchronize the release operation instead. > > > > Signed-off-by: Tejun Heo <tj@kernel.org> > > Reported-by: Tony Lindgren <tony@atomide.com> > > Fixes: 0e67db2f9fe9 ("kernfs: add kernfs_ops->open/release() callbacks") > > --- > > Hello, > > > > Tony, can you please verify that this resolves the lockdep warnings > > that you've been seeing on linux-next? > > Yes thanks this fixes the issue I was seeing: > > Tested-by: Tony Lindgren <tony@atomide.com> > > > Greg, this is a fix for the kernfs patches which are being routed > > through the cgroup tree. Once Tony confirms, I'll apply this patch on > > top.
Great, no objection from me:
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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