A problem about modprobe ingenic-drm failed is triggered with the following log given:
[ 303.561088] Error: Driver 'ingenic-ipu' is already registered, aborting... modprobe: ERROR: could not insert 'ingenic_drm': Device or resource busy
The reason is that ingenic_drm_init() returns platform_driver_register() directly without checking its return value, if platform_driver_register() failed, it returns without unregistering ingenic_ipu_driver_ptr, resulting the ingenic-drm can never be installed later. A simple call graph is shown as below:
ingenic_drm_init() platform_driver_register() # ingenic_ipu_driver_ptr are registered platform_driver_register() driver_register() bus_add_driver() priv = kzalloc(...) # OOM happened # return without unregister ingenic_ipu_driver_ptr
Fixing this problem by checking the return value of platform_driver_register() and do platform_unregister_drivers() if error happened.
Fixes: fc1acf317b01 ("drm/ingenic: Add support for the IPU") Signed-off-by: Yuan Can yuancan@huawei.com Cc: stable@vger.kernel.org --- Changes in v2: - Add missing Cc: stable@vger.kernel.org
drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c index ab0515d2c420..4499a04f7c13 100644 --- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c +++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c @@ -1629,7 +1629,11 @@ static int ingenic_drm_init(void) return err; }
- return platform_driver_register(&ingenic_drm_driver); + err = platform_driver_register(&ingenic_drm_driver); + if (IS_ENABLED(CONFIG_DRM_INGENIC_IPU) && err) + platform_driver_unregister(ingenic_ipu_driver_ptr); + + return err; } module_init(ingenic_drm_init);