[PATCH 6.1 0356/1146] media: platform: exynos4-is: Fix error handling in fimc_md_init()

Greg Kroah-Hartman
2022-12-28T15:49:12Z

From: Yuan Can <yuancan@huawei.com>

[ Upstream commit b434422c45282a0573d8123239abc41fa72665d4 ]

A problem about modprobe s5p_fimc failed is triggered with the
following log given:

[ 272.075275] Error: Driver 'exynos4-fimc' is already registered, aborting...
modprobe: ERROR: could not insert 's5p_fimc': Device or resource busy

The reason is that fimc_md_init() returns platform_driver_register()
directly without checking its return value, if platform_driver_register()
failed, it returns without unregister fimc_driver, resulting the
s5p_fimc can never be installed later.
A simple call graph is shown as below:

fimc_md_init()
fimc_register_driver() # register fimc_driver
platform_driver_register()
platform_driver_register()
driver_register()
bus_add_driver()
dev = kzalloc(...) # OOM happened
# return without unregister fimc_driver

Fix by unregister fimc_driver when platform_driver_register() returns
error.

Fixes: d3953223b090 ("[media] s5p-fimc: Add the media device driver")
Signed-off-by: Yuan Can <yuancan@huawei.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/platform/samsung/exynos4-is/fimc-core.c | 2 +-
drivers/media/platform/samsung/exynos4-is/media-dev.c | 6 +++++-
2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/samsung/exynos4-is/fimc-core.c b/drivers/media/platform/samsung/exynos4-is/fimc-core.c
index 91cc8d58a663..1791100b6935 100644
--- a/drivers/media/platform/samsung/exynos4-is/fimc-core.c
+++ b/drivers/media/platform/samsung/exynos4-is/fimc-core.c
@@ -1173,7 +1173,7 @@ int __init fimc_register_driver(void)
return platform_driver_register(&fimc_driver);
}

-void __exit fimc_unregister_driver(void)
+void fimc_unregister_driver(void)
{
platform_driver_unregister(&fimc_driver);
}
diff --git a/drivers/media/platform/samsung/exynos4-is/media-dev.c b/drivers/media/platform/samsung/exynos4-is/media-dev.c
index 383a1e0ab912..2f3071acb9c9 100644
--- a/drivers/media/platform/samsung/exynos4-is/media-dev.c
+++ b/drivers/media/platform/samsung/exynos4-is/media-dev.c
@@ -1584,7 +1584,11 @@ static int __init fimc_md_init(void)
if (ret)
return ret;

- return platform_driver_register(&fimc_md_driver);
+ ret = platform_driver_register(&fimc_md_driver);
+ if (ret)
+ fimc_unregister_driver();
+
+ return ret;
}

static void __exit fimc_md_exit(void)
--
2.35.1