Re: [PATCH v2 07/15] ARM: rockchip: fix a leaked reference by adding missing of_node_put

From: Heiko Stuebner
Date: Tue Apr 23 2019 - 13:49:01 EST


Hi,

sorry that this took so long to look at, but I think it needs a bit of
rework, see below:

Am Dienstag, 5. März 2019, 12:33:58 CEST schrieb Wen Yang:
> The call to of_get_next_child returns a node pointer with refcount
> incremented thus it must be explicitly decremented after the last
> usage.
>
> Detected by coccinelle with the following warnings:
> ./arch/arm/mach-rockchip/pm.c:269:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 259, but without a corresponding object release within this function.
> ./arch/arm/mach-rockchip/pm.c:275:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 259, but without a corresponding object release within this function
> ./arch/arm/mach-rockchip/platsmp.c:280:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 271, but without a corresponding object release within this function.
> ./arch/arm/mach-rockchip/platsmp.c:284:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 271, but without a corresponding object release within this function.
> ./arch/arm/mach-rockchip/platsmp.c:288:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 271, but without a corresponding object release within this function.
> ./arch/arm/mach-rockchip/platsmp.c:302:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 293, but without a corresponding object release within this function.
> ./arch/arm/mach-rockchip/platsmp.c:250:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 241, but without a corresponding object release within this function.
> ./arch/arm/mach-rockchip/platsmp.c:260:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 241, but without a corresponding object release within this function.
> ./arch/arm/mach-rockchip/platsmp.c:263:1-7: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 241, but without a corresponding object release within this function.
>
> Signed-off-by: Wen Yang <wen.yang99@xxxxxxxxxx>
> Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
> Cc: Russell King <linux@xxxxxxxxxxxxxxx>
> Cc: Heiko Stuebner <heiko@xxxxxxxxx>
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc: linux-rockchip@xxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> ---
> v2->v1: add a missing space between "adding" and "missing"
>
> arch/arm/mach-rockchip/platsmp.c | 12 ++++++++----
> arch/arm/mach-rockchip/pm.c | 11 ++++++-----
> 2 files changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm/mach-rockchip/platsmp.c b/arch/arm/mach-rockchip/platsmp.c
> index 51984a4..f93d64e 100644
> --- a/arch/arm/mach-rockchip/platsmp.c
> +++ b/arch/arm/mach-rockchip/platsmp.c
> @@ -277,19 +277,20 @@ static void __init rockchip_smp_prepare_cpus(unsigned int max_cpus)
> sram_base_addr = of_iomap(node, 0);

just do the of_node_put here and drop the whole error gotos?
Because node in this case only holds the possible pointer to

> if (!sram_base_addr) {
> pr_err("%s: could not map sram registers\n", __func__);
> - return;
> + goto out_put_node;
> }
>
> if (has_pmu && rockchip_smp_prepare_pmu())
> - return;
> + goto out_put_node;
>
> if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A9) {
> if (rockchip_smp_prepare_sram(node))
> - return;
> + goto out_put_node;
>
> /* enable the SCU power domain */
> pmu_set_power_domain(PMU_PWRDN_SCU, true);
>
> + of_node_put(node);
> node = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
> if (!node) {
> pr_err("%s: missing scu\n", __func__);
> @@ -299,7 +300,7 @@ static void __init rockchip_smp_prepare_cpus(unsigned int max_cpus)
> scu_base_addr = of_iomap(node, 0);

similarly just put the scu node here?

> if (!scu_base_addr) {
> pr_err("%s: could not map scu registers\n", __func__);
> - return;
> + goto out_put_node;
> }
>
> /*
> @@ -321,6 +322,9 @@ static void __init rockchip_smp_prepare_cpus(unsigned int max_cpus)
> /* Make sure that all cores except the first are really off */
> for (i = 1; i < ncores; i++)
> pmu_set_power_domain(0 + i, false);
> +
> +out_put_node:
> + of_node_put(node);
> }
>
> static void __init rk3036_smp_prepare_cpus(unsigned int max_cpus)
> diff --git a/arch/arm/mach-rockchip/pm.c b/arch/arm/mach-rockchip/pm.c
> index 0592534..43a16c9 100644
> --- a/arch/arm/mach-rockchip/pm.c
> +++ b/arch/arm/mach-rockchip/pm.c
> @@ -266,25 +266,26 @@ static int rk3288_suspend_init(struct device_node *np)
> rk3288_bootram_base = of_iomap(sram_np, 0);
> if (!rk3288_bootram_base) {
> pr_err("%s: could not map bootram base\n", __func__);

just add a regular of_node_put here?

> - return -ENOMEM;
> + ret = -ENOMEM;
> + goto out_put_node;
> }
>
> ret = of_address_to_resource(sram_np, 0, &res);
> if (ret) {
> pr_err("%s: could not get bootram phy addr\n", __func__);

and here as well? Not having to follow gotos might improve readability
especially as after here the node isn't used anymore as indicated by the
already existing of_node_put below which should be kept.


Heiko

> - return ret;
> + goto out_put_node;
> }
> rk3288_bootram_phy = res.start;
>
> - of_node_put(sram_np);
> -
> rk3288_config_bootdata();
>
> /* copy resume code and data to bootsram */
> memcpy(rk3288_bootram_base, rockchip_slp_cpu_resume,
> rk3288_bootram_sz);
>
> - return 0;
> +out_put_node:
> + of_node_put(sram_np);
> + return ret;
> }
>
> static const struct platform_suspend_ops rk3288_suspend_ops = {
>