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drm/bridge: megachips: Fix error handling in i2c_register_driver()

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[ Upstream commit 4ecff954c370b82bce45bdca2846c5c5563e8a8a ]

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@huawei.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Tested-by: Ian Ray <ian.ray@ge.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221108091226.114524-1-yuancan@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Yuan Can 2022-11-08 09:12:26 +00:00 committed by Greg Kroah-Hartman
parent 181fb5efb6
commit 5b9bcb33cf
1 changed files with 5 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
View File

@ -444,7 +444,11 @@ 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;
}
module_init(stdpxxxx_ge_b850v3_init);