for 4.2 ??? Re: [PATCH V3 2/2] block/nbd: fix memory leak in nbd_open()

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

It's just a memory leak, but it's a regression in 4.2.

Should we take it into 4.2?


29.11.2019 10:25, pannengyuan@huawei.com wrote:
> From: PanNengyuan <pannengyuan@huawei.com>
> 
> 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 <euler.robot@huawei.com>
> Signed-off-by: PanNengyuan <pannengyuan@huawei.com>

May add:

Fixes: 8f071c9db506e03ab

(I found it just by git log -p, could you please check it by your reproduce?)

Ohh, that's my commit, I'm sorry. If you discovered this commit by yourself,
and added Fixes: tag and myself to CC, I'd have reviewed it a lot earlier..

> ---
> Changes v2 to v1:
> - add a new function to do the common cleanups (suggested by Stefano
>    Garzarella).
> ---
> Changes v3 to v2:
> - split in two patches(suggested by Stefano Garzarella)
> ---
>   block/nbd.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/block/nbd.c b/block/nbd.c
> index 5805979..09d6925 100644
> --- a/block/nbd.c
> +++ b/block/nbd.c
> @@ -1889,6 +1889,7 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
>   
>       ret = nbd_client_connect(bs, errp);
>       if (ret < 0) {
> +        nbd_free_bdrvstate_prop(s);
>           return ret;
>       }
>       /* successfully connected */
> 

Thanks for fixing!

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

-- 
Best regards,
Vladimir