[PATCH v3] firmware: qcom: scm: Fix incorrect of_node_put calls in scm_init

[PATCH v3] firmware: qcom: scm: Fix incorrect of_node_put calls in scm_init

[Loys Ollivier]

When using other platform architectures, in the init of the qcom_scm
driver, of_node_put is called on /firmware if no qcom dt is found.
This results in a kernel error: Bad of_node_put() on /firmware.

These calls to of_node_put from the qcom_scm init are unnecessary as
of_find_matching_node and of_platform_populate are calling it
automatically.

Remove the calls to of_node_put() on fw_np.

Fixes: d0f6fa7ba2d6 ("firmware: qcom: scm: Convert SCM to platform driver")
Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Loys Ollivier <lollivier@baylibre.com>
---
 drivers/firmware/qcom_scm.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index af4c75217ea6..f6d7b7cffe0c 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -632,17 +632,13 @@ static int __init qcom_scm_init(void)
 
 	np = of_find_matching_node(fw_np, qcom_scm_dt_match);
 
-	if (!np) {
-		of_node_put(fw_np);
+	if (!np)
 		return -ENODEV;
-	}
 
 	of_node_put(np);
 
 	ret = of_platform_populate(fw_np, qcom_scm_dt_match, NULL, NULL);
 
-	of_node_put(fw_np);
-
 	if (ret)
 		return ret;
 
-- 
2.7.4

Re: [PATCH v3] firmware: qcom: scm: Fix incorrect of_node_put calls in scm_init

[Loys Ollivier]

Hello guys,

Any news on this fix ? Anything else you need on my side ?

Thanks

On 15/12/2017 14:40, Loys Ollivier wrote:
> When using other platform architectures, in the init of the qcom_scm
> driver, of_node_put is called on /firmware if no qcom dt is found.
> This results in a kernel error: Bad of_node_put() on /firmware.
> 
> These calls to of_node_put from the qcom_scm init are unnecessary as
> of_find_matching_node and of_platform_populate are calling it
> automatically.
> 
> Remove the calls to of_node_put() on fw_np.
> 
> Fixes: d0f6fa7ba2d6 ("firmware: qcom: scm: Convert SCM to platform driver")
> Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
> Signed-off-by: Loys Ollivier <lollivier@baylibre.com>
> ---
>  drivers/firmware/qcom_scm.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> index af4c75217ea6..f6d7b7cffe0c 100644
> --- a/drivers/firmware/qcom_scm.c
> +++ b/drivers/firmware/qcom_scm.c
> @@ -632,17 +632,13 @@ static int __init qcom_scm_init(void)
>  
>  	np = of_find_matching_node(fw_np, qcom_scm_dt_match);
>  
> -	if (!np) {
> -		of_node_put(fw_np);
> +	if (!np)
>  		return -ENODEV;
> -	}
>  
>  	of_node_put(np);
>  
>  	ret = of_platform_populate(fw_np, qcom_scm_dt_match, NULL, NULL);
>  
> -	of_node_put(fw_np);
> -
>  	if (ret)
>  		return ret;
>  
> 

Re: [PATCH v3] firmware: qcom: scm: Fix incorrect of_node_put calls in scm_init

[Bjorn Andersson]

On Fri 15 Dec 05:40 PST 2017, Loys Ollivier wrote:

> When using other platform architectures, in the init of the qcom_scm
> driver, of_node_put is called on /firmware if no qcom dt is found.
> This results in a kernel error: Bad of_node_put() on /firmware.
> 
> These calls to of_node_put from the qcom_scm init are unnecessary as
> of_find_matching_node and of_platform_populate are calling it
> automatically.
> 
> Remove the calls to of_node_put() on fw_np.
> 
> Fixes: d0f6fa7ba2d6 ("firmware: qcom: scm: Convert SCM to platform driver")
> Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
> Signed-off-by: Loys Ollivier <lollivier@baylibre.com>

Hi Loys,

Your patch is correct! We are however removing all this logic from
qcom_scm_init() in v4.16.

See:
https://git.kernel.org/pub/scm/linux/kernel/git/agross/linux.git/commit/?h=for-next&id=3aa0582fdb824139630298880fbf78d4ac774d3c
https://git.kernel.org/pub/scm/linux/kernel/git/agross/linux.git/commit/?h=for-next&id=3aa0582fdb824139630298880fbf78d4ac774d3c

Regards,
Bjorn

Re: [PATCH v3] firmware: qcom: scm: Fix incorrect of_node_put calls in scm_init

[Sudeep Holla]

Hi Loys, Bjorn,

On Tue, Jan 16, 2018 at 08:45:49AM -0800, Bjorn Andersson wrote:
> On Fri 15 Dec 05:40 PST 2017, Loys Ollivier wrote:
> 
> > When using other platform architectures, in the init of the qcom_scm
> > driver, of_node_put is called on /firmware if no qcom dt is found.
> > This results in a kernel error: Bad of_node_put() on /firmware.
> > 
> > These calls to of_node_put from the qcom_scm init are unnecessary as
> > of_find_matching_node and of_platform_populate are calling it
> > automatically.
> > 
> > Remove the calls to of_node_put() on fw_np.
> > 
> > Fixes: d0f6fa7ba2d6 ("firmware: qcom: scm: Convert SCM to platform driver")
> > Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
> > Signed-off-by: Loys Ollivier <lollivier@baylibre.com>
> 
> Hi Loys,
> 
> Your patch is correct! We are however removing all this logic from
> qcom_scm_init() in v4.16.
>

Unfortunately I seem to have carried the same issue to the new place.
I am fine if Loys wants to post the patch for the same. Let me know if you
want me to post, I have one handy(attached for the reference)

Regards,
Sudeep

-->8

>From 7a563a6f793796339ba1b7a167a77f7353bdd58d Mon Sep 17 00:00:00 2001
From: Sudeep Holla <sudeep.holla@arm.com>
Date: Tue, 16 Jan 2018 17:17:28 +0000
Subject: [PATCH] of: platform: fix OF node refcount leak

We need to call of_node_put() for device nodes obtained with
of_find_node_by_path().

Reported-by: Loys Ollivier <lollivier@baylibre.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
 drivers/of/platform.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 6a01dab597c7..c00d81dfac0b 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -514,8 +514,10 @@ static int __init of_platform_default_populate_init(void)
 		of_platform_device_create(node, NULL, NULL);
 
 	node = of_find_node_by_path("/firmware");
-	if (node)
+	if (node) {
 		of_platform_populate(node, NULL, NULL, NULL);
+		of_node_put(node);
+	}
 
 	/* Populate everything else. */
 	of_platform_default_populate(NULL, NULL, NULL);
-- 
2.7.4

Re: [PATCH v3] firmware: qcom: scm: Fix incorrect of_node_put calls in scm_init

[Andy Gross]

On Tue, Jan 16, 2018 at 08:45:49AM -0800, Bjorn Andersson wrote:
> On Fri 15 Dec 05:40 PST 2017, Loys Ollivier wrote:
> 
> > When using other platform architectures, in the init of the qcom_scm
> > driver, of_node_put is called on /firmware if no qcom dt is found.
> > This results in a kernel error: Bad of_node_put() on /firmware.
> > 
> > These calls to of_node_put from the qcom_scm init are unnecessary as
> > of_find_matching_node and of_platform_populate are calling it
> > automatically.
> > 
> > Remove the calls to of_node_put() on fw_np.
> > 
> > Fixes: d0f6fa7ba2d6 ("firmware: qcom: scm: Convert SCM to platform driver")
> > Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
> > Signed-off-by: Loys Ollivier <lollivier@baylibre.com>
> 
> Hi Loys,
> 
> Your patch is correct! We are however removing all this logic from
> qcom_scm_init() in v4.16.
> 
> See:
> https://git.kernel.org/pub/scm/linux/kernel/git/agross/linux.git/commit/?h=for-next&id=3aa0582fdb824139630298880fbf78d4ac774d3c
> https://git.kernel.org/pub/scm/linux/kernel/git/agross/linux.git/commit/?h=for-next&id=3aa0582fdb824139630298880fbf78d4ac774d3c


Yeah sorry for the delay in response.  I pulled in the second part of a separate
fix that removes all that code from the qcom_scm.  It made more sense to do it
automatically from the base code.

Andy