[PATCH v3 1/2] soc: imx: gpcv2: Do not pass static memory as platform data

From: Andrey Smirnov
Date: Tue Apr 10 2018 - 14:34:55 EST


Platform device core assumes the ownership of dev.platform_data as
well as that it is dynamically allocated and it will try to kfree it
as a part of platform_device_release(). Change the code to use
platform_device_add_data() n instead of a pointer to a static memory
to avoid causing a BUG() when calling platform_device_put().

The problem can be reproduced by artificially enabling the error path
of platform_device_add() call (around line 357).

Note that this change also allows us to constify imx7_pgc_domains,
since we no longer need to be able to modify it.

Cc: Shawn Guo <shawnguo@xxxxxxxxxx>
Cc: Stefan Agner <stefan@xxxxxxxx>
Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
---

Changes since [v2]:

- Patch reworked to use platform_device_add_data() as per request from Shawn

Changes since [v1]:

- Replaced devm_kzalloc() with devm_kmalloc() as per suggestion from Stefan

[v1] lkml.kernel.org/r/20180110161608.13015-1-andrew.smirnov@xxxxxxxxx
[v2] lkml.kernel.org/r/20180122150748.1742-1-andrew.smirnov@xxxxxxxxx

drivers/soc/imx/gpcv2.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/soc/imx/gpcv2.c b/drivers/soc/imx/gpcv2.c
index afc7ecc3c187..f4e3bd40c72e 100644
--- a/drivers/soc/imx/gpcv2.c
+++ b/drivers/soc/imx/gpcv2.c
@@ -155,7 +155,7 @@ static int imx7_gpc_pu_pgc_sw_pdn_req(struct generic_pm_domain *genpd)
return imx7_gpc_pu_pgc_sw_pxx_req(genpd, false);
}

-static struct imx7_pgc_domain imx7_pgc_domains[] = {
+static const struct imx7_pgc_domain imx7_pgc_domains[] = {
[IMX7_POWER_DOMAIN_MIPI_PHY] = {
.genpd = {
.name = "mipi-phy",
@@ -321,11 +321,6 @@ static int imx_gpcv2_probe(struct platform_device *pdev)
continue;
}

- domain = &imx7_pgc_domains[domain_index];
- domain->regmap = regmap;
- domain->genpd.power_on = imx7_gpc_pu_pgc_sw_pup_req;
- domain->genpd.power_off = imx7_gpc_pu_pgc_sw_pdn_req;
-
pd_pdev = platform_device_alloc("imx7-pgc-domain",
domain_index);
if (!pd_pdev) {
@@ -334,7 +329,20 @@ static int imx_gpcv2_probe(struct platform_device *pdev)
return -ENOMEM;
}

- pd_pdev->dev.platform_data = domain;
+ ret = platform_device_add_data(pd_pdev,
+ &imx7_pgc_domains[domain_index],
+ sizeof(imx7_pgc_domains[domain_index]));
+ if (ret) {
+ platform_device_put(pd_pdev);
+ of_node_put(np);
+ return ret;
+ }
+
+ domain = pd_pdev->dev.platform_data;
+ domain->regmap = regmap;
+ domain->genpd.power_on = imx7_gpc_pu_pgc_sw_pup_req;
+ domain->genpd.power_off = imx7_gpc_pu_pgc_sw_pdn_req;
+
pd_pdev->dev.parent = dev;
pd_pdev->dev.of_node = np;

--
2.14.3