* [PATCH v2] drm/bridge: megachips: Fix error handling in i2c_register_driver()
@ 2022-11-08 9:12 Yuan Can
2022-11-23 6:40 ` Ian Ray
0 siblings, 1 reply; 3+ messages in thread
From: Yuan Can @ 2022-11-08 9:12 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>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
---
Changes in v2:
- Add Andrzej's Reviewed-by
- Change to the new error return style suggested by Andrzej
drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 6 +++++-
1 file changed, 5 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..cbfa05a6767b 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 +440,11 @@ 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);
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] drm/bridge: megachips: Fix error handling in i2c_register_driver()
2022-11-08 9:12 [PATCH v2] drm/bridge: megachips: Fix error handling in i2c_register_driver() Yuan Can
@ 2022-11-23 6:40 ` Ian Ray
2022-11-29 16:58 ` Robert Foss
0 siblings, 1 reply; 3+ messages in thread
From: Ian Ray @ 2022-11-23 6:40 UTC (permalink / raw)
To: Yuan Can
Cc: neil.armstrong, architt, jernej.skrabec, martyn.welch, jonas,
dri-devel, peter.senna, robert.foss, Laurent.pinchart,
andrzej.hajda, martin.donnelly
On Tue, Nov 08, 2022 at 09:12:26AM +0000, 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.
>
Thank you!
> 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>
> ---
> Changes in v2:
> - Add Andrzej's Reviewed-by
> - Change to the new error return style suggested by Andrzej
>
> drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 6 +++++-
> 1 file changed, 5 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..cbfa05a6767b 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 +440,11 @@ 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);
>
> --
> 2.17.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] drm/bridge: megachips: Fix error handling in i2c_register_driver()
2022-11-23 6:40 ` Ian Ray
@ 2022-11-29 16:58 ` Robert Foss
0 siblings, 0 replies; 3+ messages in thread
From: Robert Foss @ 2022-11-29 16:58 UTC (permalink / raw)
To: Ian Ray
Cc: neil.armstrong, architt, martyn.welch, jonas, dri-devel,
peter.senna, Yuan Can, jernej.skrabec, Laurent.pinchart,
andrzej.hajda, martin.donnelly
On Wed, 23 Nov 2022 at 07:40, Ian Ray <ian.ray@ge.com> wrote:
>
> On Tue, Nov 08, 2022 at 09:12:26AM +0000, 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.
> >
>
> Thank you!
>
> > 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>
>
> > ---
> > Changes in v2:
> > - Add Andrzej's Reviewed-by
> > - Change to the new error return style suggested by Andrzej
> >
> > drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 6 +++++-
> > 1 file changed, 5 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..cbfa05a6767b 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 +440,11 @@ 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);
> >
> > --
> > 2.17.1
> >
Applied to drm-misc-next.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-11-08 9:12 [PATCH v2] drm/bridge: megachips: Fix error handling in i2c_register_driver() Yuan Can
2022-11-23 6:40 ` Ian Ray
2022-11-29 16:58 ` Robert Foss
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