linux-kernel - Re: [1/3] powerpc/pmac: Fix DT refcount imbalance in pmac_pic_probe

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Message-Id: <20150130040904.8F89D1402A7@ozlabs.org>
Date:	Fri, 30 Jan 2015 15:09:04 +1100 (AEDT)
From:	Michael Ellerman <mpe@...erman.id.au>
To:	Geert Uytterhoeven <geert+renesas@...der.be>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Bryan Wu <cooloney@...il.com>,
	Richard Purdie <rpurdie@...ys.net>,
	Jingoo Han <jg1.han@...sung.com>,
	Lee Jones <lee.jones@...aro.org>
Cc:	devicetree@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
	linux-kernel@...r.kernel.org,
	Geert Uytterhoeven <geert+renesas@...der.be>
Subject: Re: [1/3] powerpc/pmac: Fix DT refcount imbalance in pmac_pic_probe_oldstyle

On Wed, 2015-14-01 at 13:51:57 UTC, Geert Uytterhoeven wrote:
> of_find_node_by_name() calls of_node_put() on its "from" parameter,
> which must not be done on "master", as it's still in use, and will be
> released manually later.  This may cause a zero kref refcount.
> Use of_get_child_by_name() instead to fix this.

But of_find_node_by_name() searches *all* nodes, not just the children of the
parameter.

So this is a logic change AFAICS, and I have no idea what machines we'd need to
test on to check it.

So I think an of_node_get(master) would be safer and also fix the refcounting.

cheers
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