Re: [PATCH 5/5] net/tap: net_init_tap_one(): fix net-client leak on failure path

2021-12-23 Thread Vladimir Sementsov-Ogievskiy 

12.01.2021 07:53, Jason Wang wrote:


On 2020/12/22 上午3:06, Vladimir Sementsov-Ogievskiy wrote:

net_tap_fd_init() allocates new NetClientState through
qemu_new_net_client(). We should free it on failure path.

Signed-off-by: Vladimir Sementsov-Ogievskiy 
---

Attention: it's an intuitive patch.

I see, that net-client is leaked. May be it's still freed some tricky
way? And I don't understand the whole logic of qemu_del_net_client(),
it's just the only public interface to free net-client I found.



Your patch looks correct and it's indeed a leak.

I wonder whether it's better to do the cleanup in the free_fail label in 
net_init_tap(). The reason is that we need deal with case of multiqueue. Though 
qemu_del_net_client() can handle this but it's not clear if we do it in 
net_init_tap_one().



Sorry for so long delay :(

Now I'm thinking about reviving this series. But I don't understand what you 
mean about multiqueue.. I think, if some function allocates a resource, we 
should release the resource on failure path in this function, not in the 
caller. Good functions tries to roll-back any visible changes on failure.. What 
am I missing?



  net/tap.c | 9 -
  1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/tap.c b/net/tap.c
index 89ea04862b..ba4c34af3d 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -711,7 +711,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, 
NetClientState *peer,
  ret = tap_set_sndbuf(s->fd, tap, errp);
  if (ret < 0) {
-    return;
+    goto fail;
  }
  if (tap->has_fd || tap->has_fds) {
@@ -739,13 +739,20 @@ static void net_init_tap_one(const NetdevTapOptions *tap, 
NetClientState *peer,
  if (ret < 0) {
  if (tap->has_vhostforce && tap->vhostforce) {
  error_propagate(errp, err);
+    goto fail;
  } else {
  warn_report_err(err);
  }
  }
  } else if (vhostfdname) {
  error_setg(errp, "vhostfd(s)= is not valid without vhost");
+    goto fail;
  }
+
+    return;
+
+fail:
+    qemu_del_net_client(>nc);
  }
  static int get_fds(char *str, char *fds[], int max)





--
Best regards,
Vladimir

Re: [PATCH 5/5] net/tap: net_init_tap_one(): fix net-client leak on failure path

2021-01-11 Thread Jason Wang 



On 2020/12/22 上午3:06, Vladimir Sementsov-Ogievskiy wrote:

net_tap_fd_init() allocates new NetClientState through
qemu_new_net_client(). We should free it on failure path.

Signed-off-by: Vladimir Sementsov-Ogievskiy 
---

Attention: it's an intuitive patch.

I see, that net-client is leaked. May be it's still freed some tricky
way? And I don't understand the whole logic of qemu_del_net_client(),
it's just the only public interface to free net-client I found.



Your patch looks correct and it's indeed a leak.

I wonder whether it's better to do the cleanup in the free_fail label in 
net_init_tap(). The reason is that we need deal with case of multiqueue. 
Though qemu_del_net_client() can handle this but it's not clear if we do 
it in net_init_tap_one().


Thanks




  net/tap.c | 9 -
  1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/tap.c b/net/tap.c
index 89ea04862b..ba4c34af3d 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -711,7 +711,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, 
NetClientState *peer,
  
  ret = tap_set_sndbuf(s->fd, tap, errp);

  if (ret < 0) {
-return;
+goto fail;
  }
  
  if (tap->has_fd || tap->has_fds) {

@@ -739,13 +739,20 @@ static void net_init_tap_one(const NetdevTapOptions *tap, 
NetClientState *peer,
  if (ret < 0) {
  if (tap->has_vhostforce && tap->vhostforce) {
  error_propagate(errp, err);
+goto fail;
  } else {
  warn_report_err(err);
  }
  }
  } else if (vhostfdname) {
  error_setg(errp, "vhostfd(s)= is not valid without vhost");
+goto fail;
  }
+
+return;
+
+fail:
+qemu_del_net_client(>nc);
  }
  
  static int get_fds(char *str, char *fds[], int max)

[PATCH 5/5] net/tap: net_init_tap_one(): fix net-client leak on failure path

2020-12-21 Thread Vladimir Sementsov-Ogievskiy 
net_tap_fd_init() allocates new NetClientState through
qemu_new_net_client(). We should free it on failure path.

Signed-off-by: Vladimir Sementsov-Ogievskiy 
---

Attention: it's an intuitive patch.

I see, that net-client is leaked. May be it's still freed some tricky
way? And I don't understand the whole logic of qemu_del_net_client(),
it's just the only public interface to free net-client I found.

 net/tap.c | 9 -
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/tap.c b/net/tap.c
index 89ea04862b..ba4c34af3d 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -711,7 +711,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, 
NetClientState *peer,
 
 ret = tap_set_sndbuf(s->fd, tap, errp);
 if (ret < 0) {
-return;
+goto fail;
 }
 
 if (tap->has_fd || tap->has_fds) {
@@ -739,13 +739,20 @@ static void net_init_tap_one(const NetdevTapOptions *tap, 
NetClientState *peer,
 if (ret < 0) {
 if (tap->has_vhostforce && tap->vhostforce) {
 error_propagate(errp, err);
+goto fail;
 } else {
 warn_report_err(err);
 }
 }
 } else if (vhostfdname) {
 error_setg(errp, "vhostfd(s)= is not valid without vhost");
+goto fail;
 }
+
+return;
+
+fail:
+qemu_del_net_client(>nc);
 }
 
 static int get_fds(char *str, char *fds[], int max)
-- 
2.28.0