diff mbox series

[V3,2/2] block/nbd: fix memory leak in nbd_open()

Message ID 1575012326-51324-2-git-send-email-pannengyuan@huawei.com (mailing list archive)
State New, archived
Headers show
Series [V3,1/2] block/nbd: extract the common cleanup code | expand

Commit Message

Pan Nengyuan Nov. 29, 2019, 7:25 a.m. UTC
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>
---
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(+)

Comments

Vladimir Sementsov-Ogievskiy Dec. 3, 2019, 5:52 p.m. UTC | #1
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>
Eric Blake Dec. 3, 2019, 6:54 p.m. UTC | #2
On 12/3/19 11:52 AM, Vladimir Sementsov-Ogievskiy wrote:
> It's just a memory leak, but it's a regression in 4.2.
> 
> Should we take it into 4.2?

Sorry, I was on holiday and then jury service, so I missed any chance at 
getting this into -rc3.  The memory leak only happens on failure, and 
you'd have to be pretty desperate to purposefully attempt to open a lot 
of NBD devices where you know you'll get a failure just to trigger 
enough of a leak to cause the OOM-killer to target qemu.  So I'm fine if 
this is deferred to 5.0, and just cc's qemu-stable (now done).

I'll queue this through my NBD tree for 5.0.

> 
> 
> 29.11.2019 10:25, pannengyuan@huawei.com wrote:
>> From: PanNengyuan <pannengyuan@huawei.com>

>>
>> Reported-by: Euler Robot <euler.robot@huawei.com>
>> Signed-off-by: PanNengyuan <pannengyuan@huawei.com>

I'm not one to tell you that your name is written incorrectly, but it 
does look odd to have a single word rather than a space between two 
capitalized portions.  If that's really how you want your S-o-b and 
authorship to appear, I'm happy to preserve it; but you may want to 
consider updating your git settings, and posting a v4 with an updated 
spelling if you would prefer something different.  (It is also 
acceptable to use UTF-8 characters; some people like listing an S-o-b in 
both native characters and a Westernized variant).

> 
> May add:
> 
> Fixes: 8f071c9db506e03ab

Yes, information like that helps in deciding how long the problem has 
been present (in this case, it is indeed a regression added in 4.2, even 
if minor in nature).
Eric Blake Dec. 3, 2019, 9:59 p.m. UTC | #3
On 12/3/19 12:54 PM, Eric Blake wrote:
> On 12/3/19 11:52 AM, Vladimir Sementsov-Ogievskiy wrote:
>> It's just a memory leak, but it's a regression in 4.2.
>>
>> Should we take it into 4.2?
> 
> Sorry, I was on holiday and then jury service, so I missed any chance at 
> getting this into -rc3.  The memory leak only happens on failure, and 
> you'd have to be pretty desperate to purposefully attempt to open a lot 
> of NBD devices where you know you'll get a failure just to trigger 
> enough of a leak to cause the OOM-killer to target qemu.  So I'm fine if 
> this is deferred to 5.0, and just cc's qemu-stable (now done).
> 
> I'll queue this through my NBD tree for 5.0.

Actually, given the review comments on 1/2, we'll probably be better off 
with a v4 for the series.
Pan Nengyuan Dec. 4, 2019, 3:30 a.m. UTC | #4
On 2019/12/4 2:54, Eric Blake wrote:
> On 12/3/19 11:52 AM, Vladimir Sementsov-Ogievskiy wrote:
>> It's just a memory leak, but it's a regression in 4.2.
>>
>> Should we take it into 4.2?
> 
> Sorry, I was on holiday and then jury service, so I missed any chance at
> getting this into -rc3.  The memory leak only happens on failure, and
> you'd have to be pretty desperate to purposefully attempt to open a lot
> of NBD devices where you know you'll get a failure just to trigger
> enough of a leak to cause the OOM-killer to target qemu.  So I'm fine if
> this is deferred to 5.0, and just cc's qemu-stable (now done).
> 
> I'll queue this through my NBD tree for 5.0.
> 
>>
>>
>> 29.11.2019 10:25, pannengyuan@huawei.com wrote:
>>> From: PanNengyuan <pannengyuan@huawei.com>
> 
>>>
>>> Reported-by: Euler Robot <euler.robot@huawei.com>
>>> Signed-off-by: PanNengyuan <pannengyuan@huawei.com>
> 
> I'm not one to tell you that your name is written incorrectly, but it
> does look odd to have a single word rather than a space between two
> capitalized portions.  If that's really how you want your S-o-b and
> authorship to appear, I'm happy to preserve it; but you may want to
> consider updating your git settings, and posting a v4 with an updated
> spelling if you would prefer something different.  (It is also
> acceptable to use UTF-8 characters; some people like listing an S-o-b in
> both native characters and a Westernized variant).
> 

Thanks for your advice, I will update my git settings.

>>
>> May add:
>>
>> Fixes: 8f071c9db506e03ab
> 
> Yes, information like that helps in deciding how long the problem has
> been present (in this case, it is indeed a regression added in 4.2, even
> if minor in nature).
> 

ok, I will add it next time.
diff mbox series

Patch

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 */