Re: [PATCH] block/nbd: fix memory leak in nbd_open()

[pannengyuan]

Thanks for you suggestion, I'd be glad to do it, I will send a new
version later.

Cheers.

On 2019/11/28 18:41, Stefano Garzarella wrote:
> On Thu, Nov 28, 2019 at 06:32:49PM +0800, pannengyuan wrote:
>> Hi,
>> I think it's a better way, you can implement this new function before
>> this patch.
> 
> If you want to do it, so you can send everything together, for me there's
> no problem, it was just a suggestion.
> 
> If you don't have time, I can do it.
> 
> Cheers,
> Stefano
> 
>>
>> Thanks.
>>
>> On 2019/11/28 17:01, Stefano Garzarella wrote:
>>> On Thu, Nov 28, 2019 at 04:40:10PM +0800, address@hidden wrote:
>>>
>>> Hi,
>>> I don't know nbd code very well, the patch LGTM, but just a comment
>>> below:
>>>
>>>> From: PanNengyuan <address@hidden>
>>>>
>>>> In currently implementation there will be a memory leak when
>>>> nbd_client_connect() returns error status. Here is an easy way to 
>>>> reproduce:
>>>>
>>>> 1. run qemu-iotests as follow and check the result with asan:
>>>>     ./check -raw 143
>>>>
>>>> Following is the asan output backtrack:
>>>> Direct leak of 40 byte(s) in 1 object(s) allocated from:
>>>>     #0 0x7f629688a560 in calloc (/usr/lib64/libasan.so.3+0xc7560)
>>>>     #1 0x7f6295e7e015 in g_malloc0  (/usr/lib64/libglib-2.0.so.0+0x50015)
>>>>     #2 0x56281dab4642 in qobject_input_start_struct  
>>>> /mnt/sdb/qemu-4.2.0-rc0/qapi/qobject-input-visitor.c:295
>>>>     #3 0x56281dab1a04 in visit_start_struct  
>>>> /mnt/sdb/qemu-4.2.0-rc0/qapi/qapi-visit-core.c:49
>>>>     #4 0x56281dad1827 in visit_type_SocketAddress  
>>>> qapi/qapi-visit-sockets.c:386
>>>>     #5 0x56281da8062f in nbd_config  
>>>> /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1716
>>>>     #6 0x56281da8062f in nbd_process_options  
>>>> /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1829
>>>>     #7 0x56281da8062f in nbd_open  /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1873
>>>>
>>>> Direct leak of 15 byte(s) in 1 object(s) allocated from:
>>>>     #0 0x7f629688a3a0 in malloc (/usr/lib64/libasan.so.3+0xc73a0)
>>>>     #1 0x7f6295e7dfbd in g_malloc  (/usr/lib64/libglib-2.0.so.0+0x4ffbd)
>>>>     #2 0x7f6295e96ace in g_strdup  (/usr/lib64/libglib-2.0.so.0+0x68ace)
>>>>     #3 0x56281da804ac in nbd_process_options 
>>>> /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1834
>>>>     #4 0x56281da804ac in nbd_open  /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1873
>>>>
>>>> Indirect leak of 24 byte(s) in 1 object(s) allocated from:
>>>>     #0 0x7f629688a3a0 in malloc (/usr/lib64/libasan.so.3+0xc73a0)
>>>>     #1 0x7f6295e7dfbd in g_malloc (/usr/lib64/libglib-2.0.so.0+0x4ffbd)
>>>>     #2 0x7f6295e96ace in g_strdup (/usr/lib64/libglib-2.0.so.0+0x68ace)
>>>>     #3 0x56281dab41a3 in qobject_input_type_str_keyval   
>>>> /mnt/sdb/qemu-4.2.0-rc0/qapi/qobject-input-visitor.c:536
>>>>     #4 0x56281dab2ee9 in visit_type_str   
>>>> /mnt/sdb/qemu-4.2.0-rc0/qapi/qapi-visit-core.c:297
>>>>     #5 0x56281dad0fa1 in visit_type_UnixSocketAddress_members  
>>>> qapi/qapi-visit-sockets.c:141
>>>>     #6 0x56281dad17b6 in visit_type_SocketAddress_members      
>>>> qapi/qapi-visit-sockets.c:366
>>>>     #7 0x56281dad186a in visit_type_SocketAddress     
>>>> qapi/qapi-visit-sockets.c:393
>>>>     #8 0x56281da8062f in nbd_config   
>>>> /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1716
>>>>     #9 0x56281da8062f in nbd_process_options   
>>>> /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1829
>>>>     #10 0x56281da8062f in nbd_open  
>>>> /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1873
>>>>
>>>> Reported-by: Euler Robot <address@hidden>
>>>> Signed-off-by: PanNengyuan <address@hidden>
>>>> ---
>>>>  block/nbd.c | 5 +++++
>>>>  1 file changed, 5 insertions(+)
>>>>
>>>> diff --git a/block/nbd.c b/block/nbd.c
>>>> index 1239761..bc40a25 100644
>>>> --- a/block/nbd.c
>>>> +++ b/block/nbd.c
>>>> @@ -1881,6 +1881,11 @@ static int nbd_open(BlockDriverState *bs, QDict 
>>>> *options, int flags,
>>>>  
>>>>      ret = nbd_client_connect(bs, errp);
>>>>      if (ret < 0) {
>>>> +        object_unref(OBJECT(s->tlscreds));
>>>> +        qapi_free_SocketAddress(s->saddr);
>>>> +        g_free(s->export);
>>>> +        g_free(s->tlscredsid);
>>>> +        g_free(s->x_dirty_bitmap);
>>>
>>> Since with this patch we are doing these cleanups in 3 places (here,
>>> nbd_close(), and nbd_process_options()), should be better to add a new
>>> function to do these cleanups?
>>>
>>> Maybe I'd create a series adding a patch before this one, implementing this
>>> new function, and change this patch calling it.
>>>
>>> Thanks,
>>> Stefano
>>>
>>>
>>> .
>>>
>>
>