RE: [PATCH] usb: gadget: f_fs: don't free buffer prematurely

[Yang, Fei]

>> From: Fei Yang <fei.yang@xxxxxxxxx>
>> 
>> The following kernel panic happens due to the io_data buffer gets 
>> deallocated before the async io is completed. Add a check for the case 
>> where io_data buffer should be deallocated by ffs_user_copy_worker.
> 
> [snip]
>
> Please add tag - 'Fixes: 772a7a724f6 ("usb: gadget: f_fs: Allow scatter-gather buffers")
Sent [PATCH V2]

>> ---
>>  drivers/usb/gadget/function/f_fs.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>> 
>> diff --git a/drivers/usb/gadget/function/f_fs.c
>> b/drivers/usb/gadget/function/f_fs.c
>> index 20413c2..47be961 100644
>> --- a/drivers/usb/gadget/function/f_fs.c
>> +++ b/drivers/usb/gadget/function/f_fs.c
>> @@ -1133,7 +1133,8 @@ static ssize_t ffs_epfile_io(struct file *file,
>> struct ffs_io_data *io_data)
>>  error_mutex:
>>  	mutex_unlock(&epfile->mutex);
>>  error:
>> -	ffs_free_buffer(io_data);
>> +	if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
>> +		ffs_free_buffer(io_data);
>>  	return ret;
>>  }