Re: [PATCH] usb: f_fs: Clear OS Extended descriptor counts to zero in ffs_data_reset()

[Sriharsha Allenki <sallenki@codeaurora.org>]

Hi,
On 4/2/2020 10:10 AM, Manu Gautam wrote:
> On 4/2/2020 10:02 AM, Sriharsha Allenki wrote:
>> From: Udipto Goswami <ugoswami@codeaurora.org>
>>
>> For userspace functions using OS Descriptors, if a function also supplies
>> Extended Property descriptors currently the counts and lengths stored in
>> the ms_os_descs_ext_prop_{count,name_len,data_len} variables are not
>> getting reset to 0 during an unbind or when the epfiles are closed. If
>> the same function is re-bound and the descriptors are re-written, this
>> results in those count/length variables to monotonically increase
>> causing the VLA allocation in _ffs_func_bind() to grow larger and larger
>> at each bind/unbind cycle and eventually fail to allocate.
>>
>> Fix this by clearing the ms_os_descs_ext_prop count & lengths to 0 in
>> ffs_data_reset().
>>
>> Change-Id: I3b292fe5386ab54b53df2b9f15f07430dc3df24a
> Please remove this.
Thanks Manu, sent v2 after removing it.
>> Fixes: f0175ab51993 ("usb: gadget: f_fs: OS descriptors support")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Udipto Goswami <ugoswami@codeaurora.org>
>> Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>
>> ---
>>  drivers/usb/gadget/function/f_fs.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
>> index c81023b195c3..10f01f974f67 100644
>> --- a/drivers/usb/gadget/function/f_fs.c
>> +++ b/drivers/usb/gadget/function/f_fs.c
>> @@ -1813,6 +1813,10 @@ static void ffs_data_reset(struct ffs_data *ffs)
>>  	ffs->state = FFS_READ_DESCRIPTORS;
>>  	ffs->setup_state = FFS_NO_SETUP;
>>  	ffs->flags = 0;
>> +
>> +	ffs->ms_os_descs_ext_prop_count = 0;
>> +	ffs->ms_os_descs_ext_prop_name_len = 0;
>> +	ffs->ms_os_descs_ext_prop_data_len = 0;
>>  }
>>  
>>  
> Reviewed-by: Manu Gautam <mgautam@codeaurora.org>
Thanks,
Sriharsha