From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
To: Liang He <windhl@126.com>,
mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org
Cc: nick.child@ibm.com, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc: powernv: Fix refcount leak bug in opal-powercap
Date: Fri, 17 Jun 2022 07:01:27 +0200 [thread overview]
Message-ID: <0ca5ee14-a382-0935-66be-820975501f45@wanadoo.fr> (raw)
In-Reply-To: <20220617042038.4003704-1-windhl@126.com>
Le 17/06/2022 à 06:20, Liang He a écrit :
> In opal_powercap_init(), of_find_compatible_node() will return
> a node pointer with refcount incremented. We should use of_node_put()
> in fail path or when it is not used anymore.
>
> Besides, for_each_child_of_node() will automatically *inc* and *dec*
> refcount during iteration. However, we should add the of_node_put()
> if there is a break.
Hi,
I'm not sure that your patch is right here. Because of this *inc* and
*dec* things, do we still need to of_node_put(powercap) once we have
entered for_each_child_of_node?
I think that this reference will be released on the first iteration of
the loop.
Maybe of_node_put(powercap) should be duplicated everywhere it is
relevant and removed from the error handling path?
Or an additional reference should be taken before the loop?
Or adding a new label with "powercap = NULL" and branching there when
needed?
CJ
>
> Signed-off-by: Liang He <windhl@126.com>
> ---
> arch/powerpc/platforms/powernv/opal-powercap.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/platforms/powernv/opal-powercap.c b/arch/powerpc/platforms/powernv/opal-powercap.c
> index 64506b46e77b..b102477d3f95 100644
> --- a/arch/powerpc/platforms/powernv/opal-powercap.c
> +++ b/arch/powerpc/platforms/powernv/opal-powercap.c
> @@ -153,7 +153,7 @@ void __init opal_powercap_init(void)
> pcaps = kcalloc(of_get_child_count(powercap), sizeof(*pcaps),
> GFP_KERNEL);
> if (!pcaps)
> - return;
> + goto out_powercap;
>
> powercap_kobj = kobject_create_and_add("powercap", opal_kobj);
> if (!powercap_kobj) {
> @@ -236,6 +236,9 @@ void __init opal_powercap_init(void)
> kfree(pcaps[i].pg.name);
> }
> kobject_put(powercap_kobj);
> + of_node_put(node);
> out_pcaps:
> kfree(pcaps);
> +out_powercap:
> + of_node_put(powercap);
> }
next prev parent reply other threads:[~2022-06-17 5:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-17 4:20 [PATCH] powerpc: powernv: Fix refcount leak bug in opal-powercap Liang He
2022-06-17 5:01 ` Christophe JAILLET [this message]
2022-06-17 5:42 ` Liang He
2022-06-18 7:38 ` Christophe JAILLET
2022-06-17 14:29 ` Liang He
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