[PATCH] [media] omap3isp: don't call of_node_put

[PATCH] [media] omap3isp: don't call of_node_put

[H. Nikolaus Schaller]

of_node_put() has already been called inside of_graph_get_next_endpoint().

Otherwise we may get warnings like

[   10.118286] omap3isp 480bc000.isp: parsing endpoint /ocp/isp@480bc000/ports/port@0/endpoint, interface 0
[   10.118499] ERROR: Bad of_node_put() on /ocp/isp@480bc000/ports/port@0/endpoint
[   10.118499] CPU: 0 PID: 968 Comm: udevd Not tainted 4.7.0-rc4-letux+ #376
[   10.118530] Hardware name: Generic OMAP36xx (Flattened Device Tree)
[   10.118560] [<c010f0e0>] (unwind_backtrace) from [<c010b6d8>] (show_stack+0x10/0x14)
[   10.118591] [<c010b6d8>] (show_stack) from [<c03ecc50>] (dump_stack+0x98/0xd0)
[   10.118591] [<c03ecc50>] (dump_stack) from [<c03eecac>] (kobject_release+0x60/0x74)
[   10.118621] [<c03eecac>] (kobject_release) from [<c05ab128>] (__of_get_next_child+0x40/0x48)
[   10.118652] [<c05ab128>] (__of_get_next_child) from [<c05ab158>] (of_get_next_child+0x28/0x44)
[   10.118652] [<c05ab158>] (of_get_next_child) from [<c05ab350>] (of_graph_get_next_endpoint+0xe4/0x124)
[   10.118804] [<c05ab350>] (of_graph_get_next_endpoint) from [<bf1c88a4>] (isp_probe+0xdc/0xd80 [omap3_isp])
[   10.118896] [<bf1c88a4>] (isp_probe [omap3_isp]) from [<c0482008>] (platform_drv_probe+0x50/0xa0)
[   10.118927] [<c0482008>] (platform_drv_probe) from [<c04800e8>] (driver_probe_device+0x134/0x29c)
[   10.118957] [<c04800e8>] (driver_probe_device) from [<c04802d8>] (__driver_attach+0x88/0xac)
[   10.118957] [<c04802d8>] (__driver_attach) from [<c047e7b8>] (bus_for_each_dev+0x6c/0x90)
[   10.118957] [<c047e7b8>] (bus_for_each_dev) from [<c047f798>] (bus_add_driver+0xcc/0x1e8)
[   10.118988] [<c047f798>] (bus_add_driver) from [<c0481228>] (driver_register+0xac/0xf4)
[   10.118988] [<c0481228>] (driver_register) from [<c010192c>] (do_one_initcall+0xac/0x154)
[   10.119018] [<c010192c>] (do_one_initcall) from [<c02015bc>] (do_init_module+0x58/0x39c)
[   10.119049] [<c02015bc>] (do_init_module) from [<c01bd314>] (load_module+0xe5c/0x1004)
[   10.119049] [<c01bd314>] (load_module) from [<c01bd68c>] (SyS_finit_module+0x88/0x90)
[   10.119079] [<c01bd68c>] (SyS_finit_module) from [<c0107040>] (ret_fast_syscall+0x0/0x1c)

Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
---
 drivers/media/platform/omap3isp/isp.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
index 5d54e2c..6e2624e 100644
--- a/drivers/media/platform/omap3isp/isp.c
+++ b/drivers/media/platform/omap3isp/isp.c
@@ -2114,7 +2114,6 @@ static int isp_of_parse_nodes(struct device *dev,
 
 		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
 		if (!isd) {
-			of_node_put(node);
 			return -ENOMEM;
 		}
 
@@ -2126,7 +2125,7 @@ static int isp_of_parse_nodes(struct device *dev,
 		}
 
 		isd->asd.match.of.node = of_graph_get_remote_port_parent(node);
-		of_node_put(node);
+
 		if (!isd->asd.match.of.node) {
 			dev_warn(dev, "bad remote port parent\n");
 			return -EINVAL;
-- 
2.7.3

Re: [PATCH] [media] omap3isp: don't call of_node_put

[H. Nikolaus Schaller]

ping ping.

> Am 19.09.2016 um 11:55 schrieb H. Nikolaus Schaller <hns@goldelico.com>:
> 
> ping.
> 
>> Am 08.09.2016 um 17:48 schrieb H. Nikolaus Schaller <hns@goldelico.com>:
>> 
>> of_node_put() has already been called inside of_graph_get_next_endpoint().
>> 
>> Otherwise we may get warnings like
>> 
>> [   10.118286] omap3isp 480bc000.isp: parsing endpoint /ocp/isp@480bc000/ports/port@0/endpoint, interface 0
>> [   10.118499] ERROR: Bad of_node_put() on /ocp/isp@480bc000/ports/port@0/endpoint
>> [   10.118499] CPU: 0 PID: 968 Comm: udevd Not tainted 4.7.0-rc4-letux+ #376
>> [   10.118530] Hardware name: Generic OMAP36xx (Flattened Device Tree)
>> [   10.118560] [<c010f0e0>] (unwind_backtrace) from [<c010b6d8>] (show_stack+0x10/0x14)
>> [   10.118591] [<c010b6d8>] (show_stack) from [<c03ecc50>] (dump_stack+0x98/0xd0)
>> [   10.118591] [<c03ecc50>] (dump_stack) from [<c03eecac>] (kobject_release+0x60/0x74)
>> [   10.118621] [<c03eecac>] (kobject_release) from [<c05ab128>] (__of_get_next_child+0x40/0x48)
>> [   10.118652] [<c05ab128>] (__of_get_next_child) from [<c05ab158>] (of_get_next_child+0x28/0x44)
>> [   10.118652] [<c05ab158>] (of_get_next_child) from [<c05ab350>] (of_graph_get_next_endpoint+0xe4/0x124)
>> [   10.118804] [<c05ab350>] (of_graph_get_next_endpoint) from [<bf1c88a4>] (isp_probe+0xdc/0xd80 [omap3_isp])
>> [   10.118896] [<bf1c88a4>] (isp_probe [omap3_isp]) from [<c0482008>] (platform_drv_probe+0x50/0xa0)
>> [   10.118927] [<c0482008>] (platform_drv_probe) from [<c04800e8>] (driver_probe_device+0x134/0x29c)
>> [   10.118957] [<c04800e8>] (driver_probe_device) from [<c04802d8>] (__driver_attach+0x88/0xac)
>> [   10.118957] [<c04802d8>] (__driver_attach) from [<c047e7b8>] (bus_for_each_dev+0x6c/0x90)
>> [   10.118957] [<c047e7b8>] (bus_for_each_dev) from [<c047f798>] (bus_add_driver+0xcc/0x1e8)
>> [   10.118988] [<c047f798>] (bus_add_driver) from [<c0481228>] (driver_register+0xac/0xf4)
>> [   10.118988] [<c0481228>] (driver_register) from [<c010192c>] (do_one_initcall+0xac/0x154)
>> [   10.119018] [<c010192c>] (do_one_initcall) from [<c02015bc>] (do_init_module+0x58/0x39c)
>> [   10.119049] [<c02015bc>] (do_init_module) from [<c01bd314>] (load_module+0xe5c/0x1004)
>> [   10.119049] [<c01bd314>] (load_module) from [<c01bd68c>] (SyS_finit_module+0x88/0x90)
>> [   10.119079] [<c01bd68c>] (SyS_finit_module) from [<c0107040>] (ret_fast_syscall+0x0/0x1c)
>> 
>> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
>> ---
>> drivers/media/platform/omap3isp/isp.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>> 
>> diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
>> index 5d54e2c..6e2624e 100644
>> --- a/drivers/media/platform/omap3isp/isp.c
>> +++ b/drivers/media/platform/omap3isp/isp.c
>> @@ -2114,7 +2114,6 @@ static int isp_of_parse_nodes(struct device *dev,
>> 
>> 		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
>> 		if (!isd) {
>> -			of_node_put(node);
>> 			return -ENOMEM;
>> 		}
>> 
>> @@ -2126,7 +2125,7 @@ static int isp_of_parse_nodes(struct device *dev,
>> 		}
>> 
>> 		isd->asd.match.of.node = of_graph_get_remote_port_parent(node);
>> -		of_node_put(node);
>> +
>> 		if (!isd->asd.match.of.node) {
>> 			dev_warn(dev, "bad remote port parent\n");
>> 			return -EINVAL;
>> -- 
>> 2.7.3
>> 
> 

Re: [PATCH] [media] omap3isp: don't call of_node_put

[Laurent Pinchart]

Hi Nikolaus,

On Thursday 08 Sep 2016 17:48:33 H. Nikolaus Schaller wrote:
> of_node_put() has already been called inside of_graph_get_next_endpoint().
> 
> Otherwise we may get warnings like
> 
> [   10.118286] omap3isp 480bc000.isp: parsing endpoint
> /ocp/isp@480bc000/ports/port@0/endpoint, interface 0 [   10.118499] ERROR:
> Bad of_node_put() on /ocp/isp@480bc000/ports/port@0/endpoint [   10.118499]
> CPU: 0 PID: 968 Comm: udevd Not tainted 4.7.0-rc4-letux+ #376 [  
> 10.118530] Hardware name: Generic OMAP36xx (Flattened Device Tree) [  
> 10.118560] [<c010f0e0>] (unwind_backtrace) from [<c010b6d8>]
> (show_stack+0x10/0x14) [   10.118591] [<c010b6d8>] (show_stack) from
> [<c03ecc50>] (dump_stack+0x98/0xd0) [   10.118591] [<c03ecc50>]
> (dump_stack) from [<c03eecac>] (kobject_release+0x60/0x74) [   10.118621]
> [<c03eecac>] (kobject_release) from [<c05ab128>]
> (__of_get_next_child+0x40/0x48) [   10.118652] [<c05ab128>]
> (__of_get_next_child) from [<c05ab158>] (of_get_next_child+0x28/0x44) [  
> 10.118652] [<c05ab158>] (of_get_next_child) from [<c05ab350>]
> (of_graph_get_next_endpoint+0xe4/0x124) [   10.118804] [<c05ab350>]
> (of_graph_get_next_endpoint) from [<bf1c88a4>] (isp_probe+0xdc/0xd80
> [omap3_isp]) [   10.118896] [<bf1c88a4>] (isp_probe [omap3_isp]) from
> [<c0482008>] (platform_drv_probe+0x50/0xa0) [   10.118927] [<c0482008>]
> (platform_drv_probe) from [<c04800e8>] (driver_probe_device+0x134/0x29c) [ 
>  10.118957] [<c04800e8>] (driver_probe_device) from [<c04802d8>]
> (__driver_attach+0x88/0xac) [   10.118957] [<c04802d8>] (__driver_attach)
> from [<c047e7b8>] (bus_for_each_dev+0x6c/0x90) [   10.118957] [<c047e7b8>]
> (bus_for_each_dev) from [<c047f798>] (bus_add_driver+0xcc/0x1e8) [  
> 10.118988] [<c047f798>] (bus_add_driver) from [<c0481228>]
> (driver_register+0xac/0xf4) [   10.118988] [<c0481228>] (driver_register)
> from [<c010192c>] (do_one_initcall+0xac/0x154) [   10.119018] [<c010192c>]
> (do_one_initcall) from [<c02015bc>] (do_init_module+0x58/0x39c) [  
> 10.119049] [<c02015bc>] (do_init_module) from [<c01bd314>]
> (load_module+0xe5c/0x1004) [   10.119049] [<c01bd314>] (load_module) from
> [<c01bd68c>] (SyS_finit_module+0x88/0x90) [   10.119079] [<c01bd68c>]
> (SyS_finit_module) from [<c0107040>] (ret_fast_syscall+0x0/0x1c)
> 
> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
> ---
>  drivers/media/platform/omap3isp/isp.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/media/platform/omap3isp/isp.c
> b/drivers/media/platform/omap3isp/isp.c index 5d54e2c..6e2624e 100644
> --- a/drivers/media/platform/omap3isp/isp.c
> +++ b/drivers/media/platform/omap3isp/isp.c
> @@ -2114,7 +2114,6 @@ static int isp_of_parse_nodes(struct device *dev,
> 
>  		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
>  		if (!isd) {
> -			of_node_put(node);

I don't think this one is correct. Looking at the context

        while (notifier->num_subdevs < ISP_MAX_SUBDEVS &&
               (node = of_graph_get_next_endpoint(dev->of_node, node))) {
                struct isp_async_subdev *isd;

                isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
                if (!isd) {
                        of_node_put(node);
                        return -ENOMEM;
                }

                notifier->subdevs[notifier->num_subdevs] = &isd->asd;

                if (isp_of_parse_node(dev, node, isd)) {
                        of_node_put(node);
                        return -EINVAL;
                }

		isd->asd.match.of.node =
			of_graph_get_remote_port_parent(node);
                of_node_put(node);

                if (!isd->asd.match.of.node) {
                        dev_warn(dev, "bad remote port parent\n");
                        return -EINVAL;
                }

                isd->asd.match_type = V4L2_ASYNC_MATCH_OF;
                notifier->num_subdevs++;
        }

of_graph_get_next_endpoint() increases the reference count of the node it
returns, which needs a corresponding of_node_put() in the error paths. It
thus look like to me that the function isn't correct in that the
devm_kzalloc() and !isd->asd.match.of.node error paths.

>  			return -ENOMEM;
>  		}
> 
> @@ -2126,7 +2125,7 @@ static int isp_of_parse_nodes(struct device *dev,
>  		}
> 
>  		isd->asd.match.of.node = of_graph_get_remote_port_parent(node);
> -		of_node_put(node);
> +

This change is correct not because of_graph_get_next_endpoint() has called
of_node_put() but because it *will* call it on the next iteration.

How about the following patch instead ?

commit 4ed9893bf52c90181c8d5b1ae29a37556b89f1da
Author: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Date:   Thu Sep 29 11:41:24 2016 +0300

    omap3isp: Fix OF node double put when parsing OF graph
    
    When parsing the graph the driver loops over all endpoints using
    of_graph_get_next_endpoint(). The function handles reference counting of
    the passed and returned nodes, so the returned node's reference count
    must not be decreased manually in the normal path.
    
    Move the offending of_node_put() call to the error path that requires
    manual reference count handling.
    
    Reported-by: H. Nikolaus Schaller <hns@goldelico.com>
    Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
index 5e212668f726..f8b437cc8943 100644
--- a/drivers/media/platform/omap3isp/isp.c
+++ b/drivers/media/platform/omap3isp/isp.c
@@ -2131,23 +2131,18 @@ static int isp_of_parse_nodes(struct device *dev,
 		struct isp_async_subdev *isd;
 
 		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
-		if (!isd) {
-			of_node_put(node);
-			return -ENOMEM;
-		}
+		if (!isd)
+			goto error;
 
 		notifier->subdevs[notifier->num_subdevs] = &isd->asd;
 
-		if (isp_of_parse_node(dev, node, isd)) {
-			of_node_put(node);
-			return -EINVAL;
-		}
+		if (isp_of_parse_node(dev, node, isd))
+			goto error;
 
 		isd->asd.match.of.node = of_graph_get_remote_port_parent(node);
-		of_node_put(node);
 		if (!isd->asd.match.of.node) {
 			dev_warn(dev, "bad remote port parent\n");
-			return -EINVAL;
+			goto error;
 		}
 
 		isd->asd.match_type = V4L2_ASYNC_MATCH_OF;
@@ -2155,6 +2150,10 @@ static int isp_of_parse_nodes(struct device *dev,
 	}
 
 	return notifier->num_subdevs;
+
+error:
+	of_node_put(node);
+	return -EINVAL;
 }
 
 static int isp_subdev_notifier_bound(struct v4l2_async_notifier *async,

>  		if (!isd->asd.match.of.node) {
>  			dev_warn(dev, "bad remote port parent\n");
>  			return -EINVAL;

-- 
Regards,

Laurent Pinchart

Re: [PATCH] [media] omap3isp: don't call of_node_put

[H. Nikolaus Schaller]

Hi Laurent,

> Am 29.09.2016 um 10:54 schrieb Laurent Pinchart <laurent.pinchart@ideasonboard.com>:
> 
> Hi Nikolaus,
> 
> On Thursday 08 Sep 2016 17:48:33 H. Nikolaus Schaller wrote:
>> of_node_put() has already been called inside of_graph_get_next_endpoint().
>> 
>> Otherwise we may get warnings like
>> 
>> [   10.118286] omap3isp 480bc000.isp: parsing endpoint
>> /ocp/isp@480bc000/ports/port@0/endpoint, interface 0 [   10.118499] ERROR:
>> Bad of_node_put() on /ocp/isp@480bc000/ports/port@0/endpoint [   10.118499]
>> CPU: 0 PID: 968 Comm: udevd Not tainted 4.7.0-rc4-letux+ #376 [  
>> 10.118530] Hardware name: Generic OMAP36xx (Flattened Device Tree) [  
>> 10.118560] [<c010f0e0>] (unwind_backtrace) from [<c010b6d8>]
>> (show_stack+0x10/0x14) [   10.118591] [<c010b6d8>] (show_stack) from
>> [<c03ecc50>] (dump_stack+0x98/0xd0) [   10.118591] [<c03ecc50>]
>> (dump_stack) from [<c03eecac>] (kobject_release+0x60/0x74) [   10.118621]
>> [<c03eecac>] (kobject_release) from [<c05ab128>]
>> (__of_get_next_child+0x40/0x48) [   10.118652] [<c05ab128>]
>> (__of_get_next_child) from [<c05ab158>] (of_get_next_child+0x28/0x44) [  
>> 10.118652] [<c05ab158>] (of_get_next_child) from [<c05ab350>]
>> (of_graph_get_next_endpoint+0xe4/0x124) [   10.118804] [<c05ab350>]
>> (of_graph_get_next_endpoint) from [<bf1c88a4>] (isp_probe+0xdc/0xd80
>> [omap3_isp]) [   10.118896] [<bf1c88a4>] (isp_probe [omap3_isp]) from
>> [<c0482008>] (platform_drv_probe+0x50/0xa0) [   10.118927] [<c0482008>]
>> (platform_drv_probe) from [<c04800e8>] (driver_probe_device+0x134/0x29c) [ 
>> 10.118957] [<c04800e8>] (driver_probe_device) from [<c04802d8>]
>> (__driver_attach+0x88/0xac) [   10.118957] [<c04802d8>] (__driver_attach)
>> from [<c047e7b8>] (bus_for_each_dev+0x6c/0x90) [   10.118957] [<c047e7b8>]
>> (bus_for_each_dev) from [<c047f798>] (bus_add_driver+0xcc/0x1e8) [  
>> 10.118988] [<c047f798>] (bus_add_driver) from [<c0481228>]
>> (driver_register+0xac/0xf4) [   10.118988] [<c0481228>] (driver_register)
>> from [<c010192c>] (do_one_initcall+0xac/0x154) [   10.119018] [<c010192c>]
>> (do_one_initcall) from [<c02015bc>] (do_init_module+0x58/0x39c) [  
>> 10.119049] [<c02015bc>] (do_init_module) from [<c01bd314>]
>> (load_module+0xe5c/0x1004) [   10.119049] [<c01bd314>] (load_module) from
>> [<c01bd68c>] (SyS_finit_module+0x88/0x90) [   10.119079] [<c01bd68c>]
>> (SyS_finit_module) from [<c0107040>] (ret_fast_syscall+0x0/0x1c)
>> 
>> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
>> ---
>> drivers/media/platform/omap3isp/isp.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>> 
>> diff --git a/drivers/media/platform/omap3isp/isp.c
>> b/drivers/media/platform/omap3isp/isp.c index 5d54e2c..6e2624e 100644
>> --- a/drivers/media/platform/omap3isp/isp.c
>> +++ b/drivers/media/platform/omap3isp/isp.c
>> @@ -2114,7 +2114,6 @@ static int isp_of_parse_nodes(struct device *dev,
>> 
>> 		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
>> 		if (!isd) {
>> -			of_node_put(node);
> 
> I don't think this one is correct. Looking at the context
> 
>        while (notifier->num_subdevs < ISP_MAX_SUBDEVS &&
>               (node = of_graph_get_next_endpoint(dev->of_node, node))) {
>                struct isp_async_subdev *isd;
> 
>                isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
>                if (!isd) {
>                        of_node_put(node);
>                        return -ENOMEM;
>                }
> 
>                notifier->subdevs[notifier->num_subdevs] = &isd->asd;
> 
>                if (isp_of_parse_node(dev, node, isd)) {
>                        of_node_put(node);
>                        return -EINVAL;
>                }
> 
> 		isd->asd.match.of.node =
> 			of_graph_get_remote_port_parent(node);
>                of_node_put(node);
> 
>                if (!isd->asd.match.of.node) {
>                        dev_warn(dev, "bad remote port parent\n");
>                        return -EINVAL;
>                }
> 
>                isd->asd.match_type = V4L2_ASYNC_MATCH_OF;
>                notifier->num_subdevs++;
>        }
> 
> of_graph_get_next_endpoint() increases the reference count of the node it
> returns, which needs a corresponding of_node_put() in the error paths. It
> thus look like to me that the function isn't correct in that the
> devm_kzalloc() and !isd->asd.match.of.node error paths.

Ah ok, the of_node_put() is not always wrong.

> 
>> 			return -ENOMEM;
>> 		}
>> 
>> @@ -2126,7 +2125,7 @@ static int isp_of_parse_nodes(struct device *dev,
>> 		}
>> 
>> 		isd->asd.match.of.node = of_graph_get_remote_port_parent(node);
>> -		of_node_put(node);
>> +
> 
> This change is correct not because of_graph_get_next_endpoint() has called
> of_node_put() but because it *will* call it on the next iteration.
> 
> How about the following patch instead ?
> 
> commit 4ed9893bf52c90181c8d5b1ae29a37556b89f1da
> Author: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Date:   Thu Sep 29 11:41:24 2016 +0300
> 
>    omap3isp: Fix OF node double put when parsing OF graph
> 
>    When parsing the graph the driver loops over all endpoints using
>    of_graph_get_next_endpoint(). The function handles reference counting of
>    the passed and returned nodes, so the returned node's reference count
>    must not be decreased manually in the normal path.
> 
>    Move the offending of_node_put() call to the error path that requires
>    manual reference count handling.
> 
>    Reported-by: H. Nikolaus Schaller <hns@goldelico.com>
>    Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
> index 5e212668f726..f8b437cc8943 100644
> --- a/drivers/media/platform/omap3isp/isp.c
> +++ b/drivers/media/platform/omap3isp/isp.c
> @@ -2131,23 +2131,18 @@ static int isp_of_parse_nodes(struct device *dev,
> 		struct isp_async_subdev *isd;
> 
> 		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
> -		if (!isd) {
> -			of_node_put(node);
> -			return -ENOMEM;
> -		}
> +		if (!isd)
> +			goto error;
> 
> 		notifier->subdevs[notifier->num_subdevs] = &isd->asd;
> 
> -		if (isp_of_parse_node(dev, node, isd)) {
> -			of_node_put(node);
> -			return -EINVAL;
> -		}
> +		if (isp_of_parse_node(dev, node, isd))
> +			goto error;
> 
> 		isd->asd.match.of.node = of_graph_get_remote_port_parent(node);
> -		of_node_put(node);
> 		if (!isd->asd.match.of.node) {
> 			dev_warn(dev, "bad remote port parent\n");
> -			return -EINVAL;
> +			goto error;
> 		}
> 
> 		isd->asd.match_type = V4L2_ASYNC_MATCH_OF;
> @@ -2155,6 +2150,10 @@ static int isp_of_parse_nodes(struct device *dev,
> 	}
> 
> 	return notifier->num_subdevs;
> +
> +error:
> +	of_node_put(node);
> +	return -EINVAL;
> }
> 
> static int isp_subdev_notifier_bound(struct v4l2_async_notifier *async,
> 
>> 		if (!isd->asd.match.of.node) {
>> 			dev_warn(dev, "bad remote port parent\n");
>> 			return -EINVAL;

Seems to fix the reported warning, but obviously I can't test the error paths.

So let's go this way (until someone shows a bug in the error path).

BR and thanks,
Nikolaus

Re: [PATCH] [media] omap3isp: don't call of_node_put

[Laurent Pinchart]

Hello Nikolaus,

On Friday 30 Sep 2016 10:28:40 H. Nikolaus Schaller wrote:
> > Am 29.09.2016 um 10:54 schrieb Laurent Pinchart:
> > On Thursday 08 Sep 2016 17:48:33 H. Nikolaus Schaller wrote:
> >> of_node_put() has already been called inside
> >> of_graph_get_next_endpoint().
> >> 
> >> Otherwise we may get warnings like
> >> 
> >> [   10.118286] omap3isp 480bc000.isp: parsing endpoint
> >> /ocp/isp@480bc000/ports/port@0/endpoint, interface 0 [   10.118499]
> >> ERROR:
> >> Bad of_node_put() on /ocp/isp@480bc000/ports/port@0/endpoint [  
> >> 10.118499]
> >> CPU: 0 PID: 968 Comm: udevd Not tainted 4.7.0-rc4-letux+ #376 [
> >> 10.118530] Hardware name: Generic OMAP36xx (Flattened Device Tree) [
> >> 10.118560] [<c010f0e0>] (unwind_backtrace) from [<c010b6d8>]
> >> (show_stack+0x10/0x14) [   10.118591] [<c010b6d8>] (show_stack) from
> >> [<c03ecc50>] (dump_stack+0x98/0xd0) [   10.118591] [<c03ecc50>]
> >> (dump_stack) from [<c03eecac>] (kobject_release+0x60/0x74) [   10.118621]
> >> [<c03eecac>] (kobject_release) from [<c05ab128>]
> >> (__of_get_next_child+0x40/0x48) [   10.118652] [<c05ab128>]
> >> (__of_get_next_child) from [<c05ab158>] (of_get_next_child+0x28/0x44) [
> >> 10.118652] [<c05ab158>] (of_get_next_child) from [<c05ab350>]
> >> (of_graph_get_next_endpoint+0xe4/0x124) [   10.118804] [<c05ab350>]
> >> (of_graph_get_next_endpoint) from [<bf1c88a4>] (isp_probe+0xdc/0xd80
> >> [omap3_isp]) [   10.118896] [<bf1c88a4>] (isp_probe [omap3_isp]) from
> >> [<c0482008>] (platform_drv_probe+0x50/0xa0) [   10.118927] [<c0482008>]
> >> (platform_drv_probe) from [<c04800e8>] (driver_probe_device+0x134/0x29c)
> >> [
> >> 10.118957] [<c04800e8>] (driver_probe_device) from [<c04802d8>]
> >> (__driver_attach+0x88/0xac) [   10.118957] [<c04802d8>] (__driver_attach)
> >> from [<c047e7b8>] (bus_for_each_dev+0x6c/0x90) [   10.118957]
> >> [<c047e7b8>]
> >> (bus_for_each_dev) from [<c047f798>] (bus_add_driver+0xcc/0x1e8) [
> >> 10.118988] [<c047f798>] (bus_add_driver) from [<c0481228>]
> >> (driver_register+0xac/0xf4) [   10.118988] [<c0481228>] (driver_register)
> >> from [<c010192c>] (do_one_initcall+0xac/0x154) [   10.119018]
> >> [<c010192c>]
> >> (do_one_initcall) from [<c02015bc>] (do_init_module+0x58/0x39c) [
> >> 10.119049] [<c02015bc>] (do_init_module) from [<c01bd314>]
> >> (load_module+0xe5c/0x1004) [   10.119049] [<c01bd314>] (load_module) from
> >> [<c01bd68c>] (SyS_finit_module+0x88/0x90) [   10.119079] [<c01bd68c>]
> >> (SyS_finit_module) from [<c0107040>] (ret_fast_syscall+0x0/0x1c)
> >> 
> >> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
> >> ---
> >> drivers/media/platform/omap3isp/isp.c | 3 +--
> >> 1 file changed, 1 insertion(+), 2 deletions(-)
> >> 
> >> diff --git a/drivers/media/platform/omap3isp/isp.c
> >> b/drivers/media/platform/omap3isp/isp.c index 5d54e2c..6e2624e 100644
> >> --- a/drivers/media/platform/omap3isp/isp.c
> >> +++ b/drivers/media/platform/omap3isp/isp.c
> >> @@ -2114,7 +2114,6 @@ static int isp_of_parse_nodes(struct device *dev,
> >> 
> >> 		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
> >> 		if (!isd) {
> >> -			of_node_put(node);
> > 
> > I don't think this one is correct. Looking at the context
> > 
> >        while (notifier->num_subdevs < ISP_MAX_SUBDEVS &&
> >               (node = of_graph_get_next_endpoint(dev->of_node, node))) {
> >                struct isp_async_subdev *isd;
> >                
> >                isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
> >                if (!isd) {
> >                        of_node_put(node);
> >                        return -ENOMEM;
> >                }
> >                
> >                notifier->subdevs[notifier->num_subdevs] = &isd->asd;
> >                
> >                if (isp_of_parse_node(dev, node, isd)) {
> >                        of_node_put(node);
> >                        return -EINVAL;
> >                }
> > 		
> > 		isd->asd.match.of.node =
> > 			of_graph_get_remote_port_parent(node);
> >                of_node_put(node);
> >                
> >                if (!isd->asd.match.of.node) {
> >                        dev_warn(dev, "bad remote port parent\n");
> >                        return -EINVAL;
> >                }
> >                
> >                isd->asd.match_type = V4L2_ASYNC_MATCH_OF;
> >                notifier->num_subdevs++;
> >        }
> > 
> > of_graph_get_next_endpoint() increases the reference count of the node it
> > returns, which needs a corresponding of_node_put() in the error paths. It
> > thus look like to me that the function isn't correct in that the
> > devm_kzalloc() and !isd->asd.match.of.node error paths.
> 
> Ah ok, the of_node_put() is not always wrong.
> 
> >> 			return -ENOMEM;
> >> 		}
> >> 
> >> @@ -2126,7 +2125,7 @@ static int isp_of_parse_nodes(struct device *dev,
> >> 		}
> >> 		
> >> 		isd->asd.match.of.node =
> >> of_graph_get_remote_port_parent(node);
> >> -		of_node_put(node);
> >> +
> > 
> > This change is correct not because of_graph_get_next_endpoint() has called
> > of_node_put() but because it *will* call it on the next iteration.
> > 
> > How about the following patch instead ?
> > 
> > commit 4ed9893bf52c90181c8d5b1ae29a37556b89f1da
> > Author: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > Date:   Thu Sep 29 11:41:24 2016 +0300
> > 
> >    omap3isp: Fix OF node double put when parsing OF graph
> >    
> >    When parsing the graph the driver loops over all endpoints using
> >    of_graph_get_next_endpoint(). The function handles reference counting
> >    of the passed and returned nodes, so the returned node's reference
> >    count must not be decreased manually in the normal path.
> >    
> >    Move the offending of_node_put() call to the error path that requires
> >    manual reference count handling.
> >    
> >    Reported-by: H. Nikolaus Schaller <hns@goldelico.com>
> >    Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > 
> > diff --git a/drivers/media/platform/omap3isp/isp.c
> > b/drivers/media/platform/omap3isp/isp.c index 5e212668f726..f8b437cc8943
> > 100644
> > --- a/drivers/media/platform/omap3isp/isp.c
> > +++ b/drivers/media/platform/omap3isp/isp.c
> > @@ -2131,23 +2131,18 @@ static int isp_of_parse_nodes(struct device *dev,
> > 		struct isp_async_subdev *isd;
> > 		
> > 		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
> > -		if (!isd) {
> > -			of_node_put(node);
> > -			return -ENOMEM;
> > -		}
> > +		if (!isd)
> > +			goto error;
> > 
> > 		notifier->subdevs[notifier->num_subdevs] = &isd->asd;
> > 
> > -		if (isp_of_parse_node(dev, node, isd)) {
> > -			of_node_put(node);
> > -			return -EINVAL;
> > -		}
> > +		if (isp_of_parse_node(dev, node, isd))
> > +			goto error;
> > 
> > 		isd->asd.match.of.node =
> > of_graph_get_remote_port_parent(node);
> > -		of_node_put(node);
> > 		if (!isd->asd.match.of.node) {
> > 			dev_warn(dev, "bad remote port parent\n");
> > -			return -EINVAL;
> > +			goto error;
> > 		}
> > 		
> > 		isd->asd.match_type = V4L2_ASYNC_MATCH_OF;
> > @@ -2155,6 +2150,10 @@ static int isp_of_parse_nodes(struct device *dev,
> > 	}
> > 	
> > 	return notifier->num_subdevs;
> > +
> > +error:
> > +	of_node_put(node);
> > +	return -EINVAL;
> > }
> > 
> > static int isp_subdev_notifier_bound(struct v4l2_async_notifier *async,
> 
> Seems to fix the reported warning, but obviously I can't test the error
> paths.

Can I add

Tested-by: H. Nikolaus Schaller <hns@goldelico.com>

to the patch ?

> So let's go this way (until someone shows a bug in the error path).

-- 
Regards,

Laurent Pinchart

Re: [PATCH] [media] omap3isp: don't call of_node_put

[H. Nikolaus Schaller]

Hi,
has it been merged somewhere? I can't find it in linux-next yet.
BR and thanks,
Nikolaus

> Am 30.09.2016 um 10:52 schrieb Laurent Pinchart <laurent.pinchart@ideasonboard.com>:
> 
> Hello Nikolaus,
> 
> On Friday 30 Sep 2016 10:28:40 H. Nikolaus Schaller wrote:
>>> Am 29.09.2016 um 10:54 schrieb Laurent Pinchart:
>>> On Thursday 08 Sep 2016 17:48:33 H. Nikolaus Schaller wrote:
>>>> of_node_put() has already been called inside
>>>> of_graph_get_next_endpoint().
>>>> 
>>>> Otherwise we may get warnings like
>>>> 
>>>> [   10.118286] omap3isp 480bc000.isp: parsing endpoint
>>>> /ocp/isp@480bc000/ports/port@0/endpoint, interface 0 [   10.118499]
>>>> ERROR:
>>>> Bad of_node_put() on /ocp/isp@480bc000/ports/port@0/endpoint [  
>>>> 10.118499]
>>>> CPU: 0 PID: 968 Comm: udevd Not tainted 4.7.0-rc4-letux+ #376 [
>>>> 10.118530] Hardware name: Generic OMAP36xx (Flattened Device Tree) [
>>>> 10.118560] [<c010f0e0>] (unwind_backtrace) from [<c010b6d8>]
>>>> (show_stack+0x10/0x14) [   10.118591] [<c010b6d8>] (show_stack) from
>>>> [<c03ecc50>] (dump_stack+0x98/0xd0) [   10.118591] [<c03ecc50>]
>>>> (dump_stack) from [<c03eecac>] (kobject_release+0x60/0x74) [   10.118621]
>>>> [<c03eecac>] (kobject_release) from [<c05ab128>]
>>>> (__of_get_next_child+0x40/0x48) [   10.118652] [<c05ab128>]
>>>> (__of_get_next_child) from [<c05ab158>] (of_get_next_child+0x28/0x44) [
>>>> 10.118652] [<c05ab158>] (of_get_next_child) from [<c05ab350>]
>>>> (of_graph_get_next_endpoint+0xe4/0x124) [   10.118804] [<c05ab350>]
>>>> (of_graph_get_next_endpoint) from [<bf1c88a4>] (isp_probe+0xdc/0xd80
>>>> [omap3_isp]) [   10.118896] [<bf1c88a4>] (isp_probe [omap3_isp]) from
>>>> [<c0482008>] (platform_drv_probe+0x50/0xa0) [   10.118927] [<c0482008>]
>>>> (platform_drv_probe) from [<c04800e8>] (driver_probe_device+0x134/0x29c)
>>>> [
>>>> 10.118957] [<c04800e8>] (driver_probe_device) from [<c04802d8>]
>>>> (__driver_attach+0x88/0xac) [   10.118957] [<c04802d8>] (__driver_attach)
>>>> from [<c047e7b8>] (bus_for_each_dev+0x6c/0x90) [   10.118957]
>>>> [<c047e7b8>]
>>>> (bus_for_each_dev) from [<c047f798>] (bus_add_driver+0xcc/0x1e8) [
>>>> 10.118988] [<c047f798>] (bus_add_driver) from [<c0481228>]
>>>> (driver_register+0xac/0xf4) [   10.118988] [<c0481228>] (driver_register)
>>>> from [<c010192c>] (do_one_initcall+0xac/0x154) [   10.119018]
>>>> [<c010192c>]
>>>> (do_one_initcall) from [<c02015bc>] (do_init_module+0x58/0x39c) [
>>>> 10.119049] [<c02015bc>] (do_init_module) from [<c01bd314>]
>>>> (load_module+0xe5c/0x1004) [   10.119049] [<c01bd314>] (load_module) from
>>>> [<c01bd68c>] (SyS_finit_module+0x88/0x90) [   10.119079] [<c01bd68c>]
>>>> (SyS_finit_module) from [<c0107040>] (ret_fast_syscall+0x0/0x1c)
>>>> 
>>>> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
>>>> ---
>>>> drivers/media/platform/omap3isp/isp.c | 3 +--
>>>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>>> 
>>>> diff --git a/drivers/media/platform/omap3isp/isp.c
>>>> b/drivers/media/platform/omap3isp/isp.c index 5d54e2c..6e2624e 100644
>>>> --- a/drivers/media/platform/omap3isp/isp.c
>>>> +++ b/drivers/media/platform/omap3isp/isp.c
>>>> @@ -2114,7 +2114,6 @@ static int isp_of_parse_nodes(struct device *dev,
>>>> 
>>>> 		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
>>>> 		if (!isd) {
>>>> -			of_node_put(node);
>>> 
>>> I don't think this one is correct. Looking at the context
>>> 
>>>       while (notifier->num_subdevs < ISP_MAX_SUBDEVS &&
>>>              (node = of_graph_get_next_endpoint(dev->of_node, node))) {
>>>               struct isp_async_subdev *isd;
>>> 
>>>               isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
>>>               if (!isd) {
>>>                       of_node_put(node);
>>>                       return -ENOMEM;
>>>               }
>>> 
>>>               notifier->subdevs[notifier->num_subdevs] = &isd->asd;
>>> 
>>>               if (isp_of_parse_node(dev, node, isd)) {
>>>                       of_node_put(node);
>>>                       return -EINVAL;
>>>               }
>>> 		
>>> 		isd->asd.match.of.node =
>>> 			of_graph_get_remote_port_parent(node);
>>>               of_node_put(node);
>>> 
>>>               if (!isd->asd.match.of.node) {
>>>                       dev_warn(dev, "bad remote port parent\n");
>>>                       return -EINVAL;
>>>               }
>>> 
>>>               isd->asd.match_type = V4L2_ASYNC_MATCH_OF;
>>>               notifier->num_subdevs++;
>>>       }
>>> 
>>> of_graph_get_next_endpoint() increases the reference count of the node it
>>> returns, which needs a corresponding of_node_put() in the error paths. It
>>> thus look like to me that the function isn't correct in that the
>>> devm_kzalloc() and !isd->asd.match.of.node error paths.
>> 
>> Ah ok, the of_node_put() is not always wrong.
>> 
>>>> 			return -ENOMEM;
>>>> 		}
>>>> 
>>>> @@ -2126,7 +2125,7 @@ static int isp_of_parse_nodes(struct device *dev,
>>>> 		}
>>>> 		
>>>> 		isd->asd.match.of.node =
>>>> of_graph_get_remote_port_parent(node);
>>>> -		of_node_put(node);
>>>> +
>>> 
>>> This change is correct not because of_graph_get_next_endpoint() has called
>>> of_node_put() but because it *will* call it on the next iteration.
>>> 
>>> How about the following patch instead ?
>>> 
>>> commit 4ed9893bf52c90181c8d5b1ae29a37556b89f1da
>>> Author: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>>> Date:   Thu Sep 29 11:41:24 2016 +0300
>>> 
>>>   omap3isp: Fix OF node double put when parsing OF graph
>>> 
>>>   When parsing the graph the driver loops over all endpoints using
>>>   of_graph_get_next_endpoint(). The function handles reference counting
>>>   of the passed and returned nodes, so the returned node's reference
>>>   count must not be decreased manually in the normal path.
>>> 
>>>   Move the offending of_node_put() call to the error path that requires
>>>   manual reference count handling.
>>> 
>>>   Reported-by: H. Nikolaus Schaller <hns@goldelico.com>
>>>   Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>>> 
>>> diff --git a/drivers/media/platform/omap3isp/isp.c
>>> b/drivers/media/platform/omap3isp/isp.c index 5e212668f726..f8b437cc8943
>>> 100644
>>> --- a/drivers/media/platform/omap3isp/isp.c
>>> +++ b/drivers/media/platform/omap3isp/isp.c
>>> @@ -2131,23 +2131,18 @@ static int isp_of_parse_nodes(struct device *dev,
>>> 		struct isp_async_subdev *isd;
>>> 		
>>> 		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
>>> -		if (!isd) {
>>> -			of_node_put(node);
>>> -			return -ENOMEM;
>>> -		}
>>> +		if (!isd)
>>> +			goto error;
>>> 
>>> 		notifier->subdevs[notifier->num_subdevs] = &isd->asd;
>>> 
>>> -		if (isp_of_parse_node(dev, node, isd)) {
>>> -			of_node_put(node);
>>> -			return -EINVAL;
>>> -		}
>>> +		if (isp_of_parse_node(dev, node, isd))
>>> +			goto error;
>>> 
>>> 		isd->asd.match.of.node =
>>> of_graph_get_remote_port_parent(node);
>>> -		of_node_put(node);
>>> 		if (!isd->asd.match.of.node) {
>>> 			dev_warn(dev, "bad remote port parent\n");
>>> -			return -EINVAL;
>>> +			goto error;
>>> 		}
>>> 		
>>> 		isd->asd.match_type = V4L2_ASYNC_MATCH_OF;
>>> @@ -2155,6 +2150,10 @@ static int isp_of_parse_nodes(struct device *dev,
>>> 	}
>>> 	
>>> 	return notifier->num_subdevs;
>>> +
>>> +error:
>>> +	of_node_put(node);
>>> +	return -EINVAL;
>>> }
>>> 
>>> static int isp_subdev_notifier_bound(struct v4l2_async_notifier *async,
>> 
>> Seems to fix the reported warning, but obviously I can't test the error
>> paths.
> 
> Can I add
> 
> Tested-by: H. Nikolaus Schaller <hns@goldelico.com>
> 
> to the patch ?
> 
>> So let's go this way (until someone shows a bug in the error path).
> 
> -- 
> Regards,
> 
> Laurent Pinchart
>