* [PATCH v2] powerpc/85xx: Fix reference leak in xes_mpc85xx_setup_arch
@ 2022-06-03 12:17 Miaoqian Lin
2022-07-29 6:53 ` Michael Ellerman
0 siblings, 1 reply; 2+ messages in thread
From: Miaoqian Lin @ 2022-06-03 12:17 UTC (permalink / raw)
To: Scott Wood, Michael Ellerman, Benjamin Herrenschmidt,
Paul Mackerras, Christophe Leroy, Miaoqian Lin, Nick Child,
Nate Case, Kumar Gala, linuxppc-dev, linux-kernel
of_find_node_by_path() returns remote device nodepointer with
refcount incremented, we should use of_node_put() on it when done.
Add missing of_node_put() to avoid refcount leak.
Fixes: 3038acf9091f ("powerpc/85xx: Add platform support for X-ES MPC85xx boards")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
---
changes in v2:
- update Fixes tag.
v1 Link: https://lore.kernel.org/all/20220603120907.19999-1-linmq006@gmail.com
---
arch/powerpc/platforms/85xx/xes_mpc85xx.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/powerpc/platforms/85xx/xes_mpc85xx.c b/arch/powerpc/platforms/85xx/xes_mpc85xx.c
index 5836e4ecb7a0..93f67b430714 100644
--- a/arch/powerpc/platforms/85xx/xes_mpc85xx.c
+++ b/arch/powerpc/platforms/85xx/xes_mpc85xx.c
@@ -130,6 +130,8 @@ static void __init xes_mpc85xx_setup_arch(void)
mpc85xx_smp_init();
fsl_pci_assign_primary();
+
+ of_node_put(root);
}
machine_arch_initcall(xes_mpc8572, mpc85xx_common_publish_devices);
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] powerpc/85xx: Fix reference leak in xes_mpc85xx_setup_arch
2022-06-03 12:17 [PATCH v2] powerpc/85xx: Fix reference leak in xes_mpc85xx_setup_arch Miaoqian Lin
@ 2022-07-29 6:53 ` Michael Ellerman
0 siblings, 0 replies; 2+ messages in thread
From: Michael Ellerman @ 2022-07-29 6:53 UTC (permalink / raw)
To: Miaoqian Lin, Scott Wood, Benjamin Herrenschmidt, Paul Mackerras,
Christophe Leroy, Miaoqian Lin, Nick Child, Nate Case,
Kumar Gala, linuxppc-dev, linux-kernel
Miaoqian Lin <linmq006@gmail.com> writes:
> of_find_node_by_path() returns remote device nodepointer with
> refcount incremented, we should use of_node_put() on it when done.
> Add missing of_node_put() to avoid refcount leak.
>
> Fixes: 3038acf9091f ("powerpc/85xx: Add platform support for X-ES MPC85xx boards")
> Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
> ---
> changes in v2:
> - update Fixes tag.
> v1 Link: https://lore.kernel.org/all/20220603120907.19999-1-linmq006@gmail.com
> ---
> arch/powerpc/platforms/85xx/xes_mpc85xx.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/powerpc/platforms/85xx/xes_mpc85xx.c b/arch/powerpc/platforms/85xx/xes_mpc85xx.c
> index 5836e4ecb7a0..93f67b430714 100644
> --- a/arch/powerpc/platforms/85xx/xes_mpc85xx.c
> +++ b/arch/powerpc/platforms/85xx/xes_mpc85xx.c
> @@ -130,6 +130,8 @@ static void __init xes_mpc85xx_setup_arch(void)
> mpc85xx_smp_init();
>
> fsl_pci_assign_primary();
> +
> + of_node_put(root);
> }
For context, here is the full function:
static void __init xes_mpc85xx_setup_arch(void)
{
struct device_node *root;
const char *model = "Unknown";
root = of_find_node_by_path("/");
if (root == NULL)
return;
model = of_get_property(root, "model", NULL);
printk(KERN_INFO "X-ES MPC85xx-based single-board computer: %s\n",
model + strlen("xes,"));
xes_mpc85xx_fixups();
mpc85xx_smp_init();
fsl_pci_assign_primary();
}
So yes it's missing an of_node_put(root).
But rather than add the of_node_put(), it would be simpler to just use
of_root directly, then it doesn't need an of_node_put() at all.
But then look closer. To begin with model is assigned "Unknown", but
then unconditionally overwritten by the of_get_property() call. So
that's a waste of space.
And then if there's no model property of_get_property() will return
NULL, and then the model + strlen("xes,") would oops.
And all of that just to print the model at boot, which is not really
necessary, anyone who cares can look it up in /proc/device-tree
after the system has booted.
So please just remove the lookup and printing of model entirely.
cheers
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