* [PATCH] drm/bridge: megachips: Fix error handling in i2c_register_driver()
@ 2022-11-08 8:29 Yuan Can
2022-11-08 8:50 ` Andrzej Hajda
0 siblings, 1 reply; 3+ messages in thread
From: Yuan Can @ 2022-11-08 8:29 UTC (permalink / raw)
To: peter.senna, martin.donnelly, martyn.welch, andrzej.hajda,
neil.armstrong, robert.foss, Laurent.pinchart, jonas,
jernej.skrabec, airlied, daniel, architt, dri-devel
Cc: yuancan
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>
---
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;
}
module_init(stdpxxxx_ge_b850v3_init);
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] drm/bridge: megachips: Fix error handling in i2c_register_driver()
2022-11-08 8:29 [PATCH] drm/bridge: megachips: Fix error handling in i2c_register_driver() Yuan Can
@ 2022-11-08 8:50 ` Andrzej Hajda
2022-11-08 9:08 ` Yuan Can
0 siblings, 1 reply; 3+ messages in thread
From: Andrzej Hajda @ 2022-11-08 8:50 UTC (permalink / raw)
To: Yuan Can, peter.senna, martin.donnelly, martyn.welch,
neil.armstrong, robert.foss, Laurent.pinchart, jonas,
jernej.skrabec, airlied, daniel, architt, dri-devel
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@huawei.com>
> ---
> 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@intel.com>
Regards
Andrzej
> }
> module_init(stdpxxxx_ge_b850v3_init);
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] drm/bridge: megachips: Fix error handling in i2c_register_driver()
2022-11-08 8:50 ` Andrzej Hajda
@ 2022-11-08 9:08 ` Yuan Can
0 siblings, 0 replies; 3+ messages in thread
From: Yuan Can @ 2022-11-08 9:08 UTC (permalink / raw)
To: Andrzej Hajda, peter.senna, martin.donnelly, martyn.welch,
neil.armstrong, robert.foss, Laurent.pinchart, jonas,
jernej.skrabec, airlied, daniel, architt, dri-devel
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@huawei.com>
>> ---
>> 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@intel.com>
Thanks for your suggestion, I will change to this style with your
Reviewed-by in the v2 patch.
--
Best regards,
Yuan Can
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-11-08 8:29 [PATCH] drm/bridge: megachips: Fix error handling in i2c_register_driver() Yuan Can
2022-11-08 8:50 ` Andrzej Hajda
2022-11-08 9:08 ` Yuan Can
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