A problem about modprobe mcde_drm failed is triggered with the following
log given:
[ 2387.922993] Error: Driver 'mcde-dsi' is already registered, aborting...
[ 2387.924272] failed to register platform driver mcde_dsi_driver [mcde_drm]: -16
modprobe: ERROR: could not insert 'mcde_drm': Device or resource busy
The reason is that mcde_drm_register() returns platform_driver_register()
directly without checking its return value, if platform_driver_register()
fails, it returns without unregistering mcde_dsi_driver, resulting the
mcde_drm can never be installed later.
A simple call graph is shown as below:
mcde_drm_register()
platform_register_drivers() # mcde_dsi_driver are registered
platform_driver_register()
driver_register()
bus_add_driver()
priv = kzalloc(...) # OOM happened
# return without unregister mcde_dsi_driver
Fixing this problem by checking the return value of
platform_driver_register() and do platform_unregister_drivers() if
error happened.
Fixes: 5fc537bfd000 ("drm/mcde: Add new driver for ST-Ericsson MCDE")
Signed-off-by: Yuan Can <yuancan@xxxxxxxxxx>
---
drivers/gpu/drm/mcde/mcde_drv.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/mcde/mcde_drv.c b/drivers/gpu/drm/mcde/mcde_drv.c
index 1c4482ad507d..0391a62dc1b8 100644
--- a/drivers/gpu/drm/mcde/mcde_drv.c
+++ b/drivers/gpu/drm/mcde/mcde_drv.c
@@ -494,7 +494,12 @@ static int __init mcde_drm_register(void)
if (ret)
return ret;
- return platform_driver_register(&mcde_driver);
+ ret = platform_driver_register(&mcde_driver);
+ if (ret)
+ platform_unregister_drivers(component_drivers,
+ ARRAY_SIZE(component_drivers));
+
+ return ret;
}
static void __exit mcde_drm_unregister(void)
--
2.17.1
