Re: [PATCH] rcu: Fix wrong check in list_splice_init_rcu()

From: Chris Mason
Date: Tue Jul 19 2011 - 17:00:49 EST


Excerpts from Paul E. McKenney's message of 2011-07-19 16:27:52 -0400:
> On Tue, Jul 19, 2011 at 09:10:26PM +0200, Jan H. SchÃnherr wrote:
> > Hi.
> >
> > If I don't miss something obvious, the following patch would
> > be a good idea.
> >
> > There are currently two users of list_splice_init_rcu(): IPMI and btrfs.
> > For these, list_splice_init_rcu() is currently a NOP.
> >
> > If I interpret the code correctly, this fixes a memory leak for
> > IPMI and something probably worse for btrfs.
> >
> > The call from within btrfs was introduced only after v2.6.39 with commit
> > 1f78160 ("Btrfs: using rcu lock in the reader side of devices list") by
> > converting a list_splice_init() call.
> >
> > Therefore, this patch might be a candidate for v3.0.
>
> Excellent catch! This one has been around for some time, so my guess
> is that it goes into v3.1. Either way, I have queued it, thank you!

A good catch and thanks for the cc. The btrfs code in question here has
some other problems, and it's fine if this patch doesn't make 3.0.

-chris
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