[PATCH master] base: driver: fix double removal of child devices

[PATCH master] base: driver: fix double removal of child devices

[Ahmad Fatoum]

Child devices like an ext4 file system on a partition may be removed
twice: Once because they're in the active devices list and then once
more, because unregister_device is called for the children of its parent.

As struct bus_type::remove clears association of a driver with its
device, we can set struct device_d::driver to NULL. unregister_device
will then skip the second dev->bus->remove.

Fixes: 29f1c211d86c ("fs: don't free device in remove callback")
Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 drivers/base/driver.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/base/driver.c b/drivers/base/driver.c
index 0e04ef36868d..0fedb30161b4 100644
--- a/drivers/base/driver.c
+++ b/drivers/base/driver.c
@@ -512,7 +512,10 @@ static void devices_shutdown(void)
 
 	list_for_each_entry(dev, &active, active) {
 		if (dev->bus->remove)
+		if (dev->bus->remove) {
 			dev->bus->remove(dev);
+			dev->driver = NULL;
+		}
 	}
 }
 devshutdown_exitcall(devices_shutdown);
-- 
2.33.0


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Re: [PATCH master] base: driver: fix double removal of child devices

[Jules Maselbas]

Hi Ahmad,

On Mon, Sep 13, 2021 at 10:29:42AM +0200, Ahmad Fatoum wrote:
> Child devices like an ext4 file system on a partition may be removed
> twice: Once because they're in the active devices list and then once
> more, because unregister_device is called for the children of its parent.
> 
> As struct bus_type::remove clears association of a driver with its
> device, we can set struct device_d::driver to NULL. unregister_device
> will then skip the second dev->bus->remove.
> 
> Fixes: 29f1c211d86c ("fs: don't free device in remove callback")
> Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
> ---
>  drivers/base/driver.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/base/driver.c b/drivers/base/driver.c
> index 0e04ef36868d..0fedb30161b4 100644
> --- a/drivers/base/driver.c
> +++ b/drivers/base/driver.c
> @@ -512,7 +512,10 @@ static void devices_shutdown(void)
>  
>  	list_for_each_entry(dev, &active, active) {
>  		if (dev->bus->remove)
> +		if (dev->bus->remove) {
I think there is a typo here, this line is duplicated.

>  			dev->bus->remove(dev);
> +			dev->driver = NULL;
> +		}
>  	}
>  }
>  devshutdown_exitcall(devices_shutdown);
> -- 
> 2.33.0
> 
> 
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> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox
> 
> 





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Re: [PATCH master] base: driver: fix double removal of child devices

[Ahmad Fatoum]

Hello Jules,

On 13.09.21 12:08, Jules Maselbas wrote:
> Hi Ahmad,
> 
> On Mon, Sep 13, 2021 at 10:29:42AM +0200, Ahmad Fatoum wrote:
>> Child devices like an ext4 file system on a partition may be removed
>> twice: Once because they're in the active devices list and then once
>> more, because unregister_device is called for the children of its parent.
>>
>> As struct bus_type::remove clears association of a driver with its
>> device, we can set struct device_d::driver to NULL. unregister_device
>> will then skip the second dev->bus->remove.
>>
>> Fixes: 29f1c211d86c ("fs: don't free device in remove callback")
>> Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
>> ---
>>  drivers/base/driver.c | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/base/driver.c b/drivers/base/driver.c
>> index 0e04ef36868d..0fedb30161b4 100644
>> --- a/drivers/base/driver.c
>> +++ b/drivers/base/driver.c
>> @@ -512,7 +512,10 @@ static void devices_shutdown(void)
>>  
>>  	list_for_each_entry(dev, &active, active) {
>>  		if (dev->bus->remove)
>> +		if (dev->bus->remove) {
> I think there is a typo here, this line is duplicated.

You're right. It still worked because the condition was duplicated... ^^'

I sent out a revised v2.

Thanks,
Ahmad

> 
>>  			dev->bus->remove(dev);
>> +			dev->driver = NULL;
>> +		}
>>  	}
>>  }
>>  devshutdown_exitcall(devices_shutdown);
>> -- 
>> 2.33.0
>>
>>
>> _______________________________________________
>> barebox mailing list
>> barebox@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/barebox
>>
>>
> 
> 
> 
> 
> 
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> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox
> 


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