[PATCH v4 0/2] block/nbd: fix memory leak in nbd_open

[PATCH v4 0/2] block/nbd: fix memory leak in nbd_open

[pannengyuan]

From: Pan Nengyuan <pannengyuan@huawei.com>

This series add a new function to do the common cleanups, and fix a memory
leak in nbd_open when nbd_client_connect returns error status.

---
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)
---
Changes v4 to v3:
- replace function name from nbd_free_bdrvstate_prop to nbd_clear_bdrvstate and add Fixes tag(suggested by Eric Blake).
- remove static function prototype. (suggested by Eric Blake)

Pan Nengyuan (2):
  block/nbd: extract the common cleanup code
  block/nbd: fix memory leak in nbd_open()

 block/nbd.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

-- 
2.7.2.windows.1

[PATCH v4 1/2] block/nbd: extract the common cleanup code

[pannengyuan]

From: Pan Nengyuan <pannengyuan@huawei.com>

The BDRVNBDState cleanup code is common in two places, add
nbd_clear_bdrvstate() function to do these cleanups.

Signed-off-by: Stefano Garzarella <Stefano Garzarella>
Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
v3:
- new patch, split form 2/2 patch (suggested by Stefano Garzarella)
Changes v4 to v3:
- replace function name from nbd_free_bdrvstate_prop to
  nbd_clear_bdrvstate and set cleared fields to NULL (suggested by Eric
  Blake)
- remove static function prototype. (suggested by Eric Blake)
---
 block/nbd.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/block/nbd.c b/block/nbd.c
index 1239761..8b4a65a 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -94,6 +94,19 @@ typedef struct BDRVNBDState {
 
 static int nbd_client_connect(BlockDriverState *bs, Error **errp);
 
+void nbd_clear_bdrvstate(BDRVNBDState *s)
+{
+    object_unref(OBJECT(s->tlscreds));
+    qapi_free_SocketAddress(s->saddr);
+    s->saddr = NULL;
+    g_free(s->export);
+    s->export = NULL;
+    g_free(s->tlscredsid);
+    s->tlscredsid = NULL;
+    g_free(s->x_dirty_bitmap);
+    s->x_dirty_bitmap = NULL;
+}
+
 static void nbd_channel_error(BDRVNBDState *s, int ret)
 {
     if (ret == -EIO) {
@@ -1855,10 +1868,7 @@ static int nbd_process_options(BlockDriverState *bs, QDict *options,
 
  error:
     if (ret < 0) {
-        object_unref(OBJECT(s->tlscreds));
-        qapi_free_SocketAddress(s->saddr);
-        g_free(s->export);
-        g_free(s->tlscredsid);
+        nbd_clear_bdrvstate(s);
     }
     qemu_opts_del(opts);
     return ret;
@@ -1937,12 +1947,7 @@ static void nbd_close(BlockDriverState *bs)
     BDRVNBDState *s = bs->opaque;
 
     nbd_client_close(bs);
-
-    object_unref(OBJECT(s->tlscreds));
-    qapi_free_SocketAddress(s->saddr);
-    g_free(s->export);
-    g_free(s->tlscredsid);
-    g_free(s->x_dirty_bitmap);
+    nbd_clear_bdrvstate(s);
 }
 
 static int64_t nbd_getlength(BlockDriverState *bs)
-- 
2.7.2.windows.1

[PATCH v4 2/2] block/nbd: fix memory leak in nbd_open()

[pannengyuan]

From: Pan Nengyuan <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

Fixes: 8f071c9db506e03ab
Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Cc: qemu-stable <qemu-stable@nongnu.org>
Cc: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.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)
---
Changes v4 to v3:
- replace function name from nbd_free_bdrvstate_prop to
  nbd_clear_bdrvstate and add Fixes tag.
---
 block/nbd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/block/nbd.c b/block/nbd.c
index 8b4a65a..9062409 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -1891,6 +1891,7 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
 
     ret = nbd_client_connect(bs, errp);
     if (ret < 0) {
+        nbd_clear_bdrvstate(s);
         return ret;
     }
     /* successfully connected */
-- 
2.7.2.windows.1