From: Yuan Can yuancan@huawei.com
[ Upstream commit cf53db768a8790fdaae2fa3a81322b080285f7e5 ]
A problem about modprobe vc4 failed is triggered with the following log given:
[ 420.327987] Error: Driver 'vc4_hvs' is already registered, aborting... [ 420.333904] failed to register platform driver vc4_hvs_driver [vc4]: -16 modprobe: ERROR: could not insert 'vc4': Device or resource busy
The reason is that vc4_drm_register() returns platform_driver_register() directly without checking its return value, if platform_driver_register() fails, it returns without unregistering all the vc4 drivers, resulting the vc4 can never be installed later. A simple call graph is shown as below:
vc4_drm_register() platform_register_drivers() # all vc4 drivers are registered platform_driver_register() driver_register() bus_add_driver() priv = kzalloc(...) # OOM happened # return without unregister drivers
Fixing this problem by checking the return value of platform_driver_register() and do platform_unregister_drivers() if error happened.
Fixes: c8b75bca92cb ("drm/vc4: Add KMS support for Raspberry Pi.") Signed-off-by: Yuan Can yuancan@huawei.com Signed-off-by: Maxime Ripard maxime@cerno.tech Link: https://patchwork.freedesktop.org/patch/msgid/20221103014705.109322-1-yuanca... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/vc4/vc4_drv.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c index 52426bc8edb8..888aec1bbeee 100644 --- a/drivers/gpu/drm/vc4/vc4_drv.c +++ b/drivers/gpu/drm/vc4/vc4_drv.c @@ -404,7 +404,12 @@ static int __init vc4_drm_register(void) if (ret) return ret;
- return platform_driver_register(&vc4_platform_driver); + ret = platform_driver_register(&vc4_platform_driver); + if (ret) + platform_unregister_drivers(component_drivers, + ARRAY_SIZE(component_drivers)); + + return ret; }
static void __exit vc4_drm_unregister(void)