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Subject: Re: [PATCH] powerpc: perf: Fix refcount leak bug in imc-pmu.c
From:   Athira Rajeev <atrajeev@linux.vnet.ibm.com>
In-Reply-To: <20220618071353.4059000-1-windhl@126.com>
Date:   Mon, 27 Jun 2022 14:30:01 +0530
Cc:     Michael Ellerman <mpe@ellerman.id.au>, benh@kernel.crashing.org,
        paulus@samba.org, christophe.leroy@csgroup.eu,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
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Message-Id: <5B61320C-C37F-4B60-BE2B-461722D44742@linux.vnet.ibm.com>
References: <20220618071353.4059000-1-windhl@126.com>
To:     Liang He <windhl@126.com>
Precedence: bulk


> On 18-Jun-2022, at 12:43 PM, Liang He <windhl@126.com> wrote:
>=20
> In update_events_in_group(), of_find_node_by_phandle() will return
> a node pointer with refcount incremented. We should use of_node_put()
> in fail path or when it is not used anymore.
>=20
> Signed-off-by: Liang He <windhl@126.com>

Reviewed-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
> ---
> arch/powerpc/perf/imc-pmu.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>=20
> diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
> index d7976ab40d38..d517aba94d1b 100644
> --- a/arch/powerpc/perf/imc-pmu.c
> +++ b/arch/powerpc/perf/imc-pmu.c
> @@ -240,8 +240,10 @@ static int update_events_in_group(struct =
device_node *node, struct imc_pmu *pmu)
> 	ct =3D of_get_child_count(pmu_events);
>=20
> 	/* Get the event prefix */
> -	if (of_property_read_string(node, "events-prefix", &prefix))
> +	if (of_property_read_string(node, "events-prefix", &prefix)) {
> +		of_node_put(pmu_events);
> 		return 0;
> +	}
>=20
> 	/* Get a global unit and scale data if available */
> 	if (of_property_read_string(node, "scale", &g_scale))
> @@ -255,8 +257,10 @@ static int update_events_in_group(struct =
device_node *node, struct imc_pmu *pmu)
>=20
> 	/* Allocate memory for the events */
> 	pmu->events =3D kcalloc(ct, sizeof(struct imc_events), =
GFP_KERNEL);
> -	if (!pmu->events)
> +	if (!pmu->events) {
> +		of_node_put(pmu_events);
> 		return -ENOMEM;
> +	}
>=20
> 	ct =3D 0;
> 	/* Parse the events and update the struct */
> @@ -266,6 +270,8 @@ static int update_events_in_group(struct =
device_node *node, struct imc_pmu *pmu)
> 			ct++;
> 	}
>=20
> +	of_node_put(pmu_events);
> +
> 	/* Allocate memory for attribute group */
> 	attr_group =3D kzalloc(sizeof(*attr_group), GFP_KERNEL);
> 	if (!attr_group) {
> --=20
> 2.25.1
>=20