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

From: Andrey Smirnov
Date: Tue Apr 10 2018 - 14:34:59 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() 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 452).

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/20180110161608.13015-2-andrew.smirnov@xxxxxxxxx
[v2] lkml.kernel.org/r/20180122150748.1742-2-andrew.smirnov@xxxxxxxxx

drivers/soc/imx/gpc.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/soc/imx/gpc.c b/drivers/soc/imx/gpc.c
index c4d35f32af8d..32f0748fd067 100644
--- a/drivers/soc/imx/gpc.c
+++ b/drivers/soc/imx/gpc.c
@@ -443,17 +443,25 @@ static int imx_gpc_probe(struct platform_device *pdev)
if (domain_index >= of_id_data->num_domains)
continue;

- domain = &imx_gpc_domains[domain_index];
- domain->regmap = regmap;
- domain->ipg_rate_mhz = ipg_rate_mhz;
-
pd_pdev = platform_device_alloc("imx-pgc-power-domain",
domain_index);
if (!pd_pdev) {
of_node_put(np);
return -ENOMEM;
}
- pd_pdev->dev.platform_data = domain;
+
+ ret = platform_device_add_data(pd_pdev,
+ &imx_gpc_domains[domain_index],
+ sizeof(imx_gpc_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->ipg_rate_mhz = ipg_rate_mhz;
+
pd_pdev->dev.parent = &pdev->dev;
pd_pdev->dev.of_node = np;

--
2.14.3