[RFC 3/4] clk: samsung: exynos5: Fix kfree() of const memory on setting driver_override

From: Krzysztof Kozlowski
Date: Mon Feb 18 2019 - 05:17:04 EST

Platform driver driver_override field should not be initialized from
const memory because the core later kfree() it. If driver_override is
manually set later through sysfs, kfree() of old value leads to:

$ echo "new_value" > /sys/bus/platform/drivers/.../driver_override

kernel BUG at ../mm/slub.c:3960!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
(kfree) from [<c058e8c0>] (platform_set_driver_override+0x84/0xac)
(platform_set_driver_override) from [<c058e908>] (driver_override_store+0x20/0x34)
(driver_override_store) from [<c031f778>] (kernfs_fop_write+0x100/0x1dc)
(kernfs_fop_write) from [<c0296de8>] (__vfs_write+0x2c/0x17c)
(__vfs_write) from [<c02970c4>] (vfs_write+0xa4/0x188)
(vfs_write) from [<c02972e8>] (ksys_write+0x4c/0xac)
(ksys_write) from [<c0101000>] (ret_fast_syscall+0x0/0x28)

Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
drivers/clk/samsung/clk-exynos5-subcmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/samsung/clk-exynos5-subcmu.c b/drivers/clk/samsung/clk-exynos5-subcmu.c
index d07ef26bd052..880d92ad20e8 100644
--- a/drivers/clk/samsung/clk-exynos5-subcmu.c
+++ b/drivers/clk/samsung/clk-exynos5-subcmu.c
@@ -143,7 +143,7 @@ static int __init exynos5_clk_register_subcmu(struct device *parent,
return -ENOMEM;

pdev->dev.parent = parent;
- pdev->driver_override = "exynos5-subcmu";
+ platform_set_driver_override(pdev, "exynos5-subcmu");
platform_set_drvdata(pdev, (void *)info);
of_genpd_add_device(&genpdspec, &pdev->dev);
ret = platform_device_add(pdev);