| Message ID | 20220309111033.24487-1-linmq006@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | usb: musb: Fix missing of_node_put() in omap2430_probe | expand |
On Wed, Mar 09, 2022 at 11:10:33AM +0000, Miaoqian Lin wrote: > The device_node pointer is returned by of_parse_phandle() with refcount > incremented. We should use of_node_put() on it when done. > > Fixes: 8934d3e4d0e7 ("usb: musb: omap2430: Don't use omap_get_control_dev()") > Signed-off-by: Miaoqian Lin <linmq006@gmail.com> > --- > drivers/usb/musb/omap2430.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/usb/musb/omap2430.c b/drivers/usb/musb/omap2430.c > index 7d4d0713f4f0..4a963cfa385b 100644 > --- a/drivers/usb/musb/omap2430.c > +++ b/drivers/usb/musb/omap2430.c > @@ -363,6 +363,7 @@ static int omap2430_probe(struct platform_device *pdev) > control_node = of_parse_phandle(np, "ctrl-module", 0); > if (control_node) { > control_pdev = of_find_device_by_node(control_node); > + of_node_put(control_node); > if (!control_pdev) { > dev_err(&pdev->dev, "Failed to get control device\n"); > ret = -EINVAL; > -- > 2.17.1 > How was this tested?
On Wed, Mar 09, 2022 at 12:25:03PM +0100, Greg Kroah-Hartman wrote: > On Wed, Mar 09, 2022 at 11:10:33AM +0000, Miaoqian Lin wrote: > > The device_node pointer is returned by of_parse_phandle() with refcount > > incremented. We should use of_node_put() on it when done. > > > > Fixes: 8934d3e4d0e7 ("usb: musb: omap2430: Don't use omap_get_control_dev()") > > Signed-off-by: Miaoqian Lin <linmq006@gmail.com> > > --- > > drivers/usb/musb/omap2430.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/usb/musb/omap2430.c b/drivers/usb/musb/omap2430.c > > index 7d4d0713f4f0..4a963cfa385b 100644 > > --- a/drivers/usb/musb/omap2430.c > > +++ b/drivers/usb/musb/omap2430.c > > @@ -363,6 +363,7 @@ static int omap2430_probe(struct platform_device *pdev) > > control_node = of_parse_phandle(np, "ctrl-module", 0); > > if (control_node) { > > control_pdev = of_find_device_by_node(control_node); > > + of_node_put(control_node); > > if (!control_pdev) { > > dev_err(&pdev->dev, "Failed to get control device\n"); > > ret = -EINVAL; > > -- > > 2.17.1 > > > > How was this tested? Hi, Greg Kroah-Hartman I mainly went through the specifications of of_parse_phandle() and of_find_device_by_node(), and checked their usages in the codebase to infer their correct usages then found out the deviant one, and manually confirmed it. In doc of of_parse_phandle() it mentions : > Return: The device_node pointer with refcount incremented. Use > * of_node_put() on it when done. In the doc of and of_find_device_by_node() it mentions: > * Takes a reference to the embedded struct device which needs to > be dropped > * after use. In this case, control_node is a local variable, and it never be used after of_find_device_by_node(), of_find_device_by_node() call will take its own reference. So the reference holded by control_node should be released. I checked the usages pattern——`$ret=of_parse_phandle();of_find_device_by_node($ret);` in codebase and most of them handle the reference after use. For example: - function pwm_omap_dmtimer_probe in drivers/pwm/pwm-omap-dmtimer.c - function mtk_smi_device_link_common in drivers/memory/mtk-smi.c, - function devm_tegra_memory_controller_get in drivers/memory/tegra/mc.c. I also took similar bugfixes for reference, for exmaple: - commit c8d0ccfd73da ("media: mtk-vpu: fix leaked of_node references") - commit 3d38faef0de1 ("ath11k: add missing of_node_put() to avoid leak") So I sent patch for this one. Still not sure if it's correct, I hope the developers could double check this, Thanks.
diff --git a/drivers/usb/musb/omap2430.c b/drivers/usb/musb/omap2430.c index 7d4d0713f4f0..4a963cfa385b 100644 --- a/drivers/usb/musb/omap2430.c +++ b/drivers/usb/musb/omap2430.c @@ -363,6 +363,7 @@ static int omap2430_probe(struct platform_device *pdev) control_node = of_parse_phandle(np, "ctrl-module", 0); if (control_node) { control_pdev = of_find_device_by_node(control_node); + of_node_put(control_node); if (!control_pdev) { dev_err(&pdev->dev, "Failed to get control device\n"); ret = -EINVAL;
The device_node pointer is returned by of_parse_phandle() with refcount incremented. We should use of_node_put() on it when done. Fixes: 8934d3e4d0e7 ("usb: musb: omap2430: Don't use omap_get_control_dev()") Signed-off-by: Miaoqian Lin <linmq006@gmail.com> --- drivers/usb/musb/omap2430.c | 1 + 1 file changed, 1 insertion(+)