在 2022/11/8 16:50, Andrzej Hajda 写道:
On 08.11.2022 09:29, Yuan Can wrote:
A problem about insmod megachips-stdpxxxx-ge-b850v3-fw.ko failed is
triggered with the following log given:
[ 4497.981497] Error: Driver 'stdp4028-ge-b850v3-fw' is already
registered, aborting...
insmod: ERROR: could not insert module
megachips-stdpxxxx-ge-b850v3-fw.ko: Device or resource busy
The reason is that stdpxxxx_ge_b850v3_init() returns i2c_add_driver()
directly without checking its return value, if i2c_add_driver() failed,
it returns without calling i2c_del_driver() on the previous i2c driver,
resulting the megachips-stdpxxxx-ge-b850v3-fw can never be installed
later.
A simple call graph is shown as below:
stdpxxxx_ge_b850v3_init()
i2c_add_driver(&stdp4028_ge_b850v3_fw_driver)
i2c_add_driver(&stdp2690_ge_b850v3_fw_driver)
i2c_register_driver()
driver_register()
bus_add_driver()
priv = kzalloc(...) # OOM happened
# return without delete stdp4028_ge_b850v3_fw_driver
Fix by calling i2c_del_driver() on stdp4028_ge_b850v3_fw_driver when
i2c_add_driver() returns error.
Fixes: fcfa0ddc18ed ("drm/bridge: Drivers for
megachips-stdpxxxx-ge-b850v3-fw (LVDS-DP++)")
Signed-off-by: Yuan Can <yuancan@xxxxxxxxxx>
---
drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
index 97359f807bfc..0d037eeefcf3 100644
--- a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
+++ b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
@@ -440,7 +440,13 @@ static int __init stdpxxxx_ge_b850v3_init(void)
if (ret)
return ret;
- return i2c_add_driver(&stdp2690_ge_b850v3_fw_driver);
+ ret = i2c_add_driver(&stdp2690_ge_b850v3_fw_driver);
+ if (ret) {
+ i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
+ return ret;
+ }
+
+ return 0;
Could be:
ret = i2c_add_driver(&stdp2690_ge_b850v3_fw_driver);
if (ret)
i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
return ret;
Up to you. Anyway:
Reviewed-by: Andrzej Hajda <andrzej.hajda@xxxxxxxxx>
Thanks for your suggestion, I will change to this style with your
Reviewed-by in the v2 patch.
--
Best regards,
Yuan Can
