[libvirt] [PATCH] virConnectUnregisterCloseCallback: Unlock @conn prior to error dispatch

[Michal Privoznik]

On 07.01.2014 18:42, Eric Blake wrote:
> On 01/07/2014 10:25 AM, Michal Privoznik wrote:
>> The function checks for @conn to be valid and locks its mutex. Then, it
>> checks if callee is unregistering the same callback that he registered
>> previously. If this fails an error is reported and  the control jumps to
>> 'error' label. Here, if @conn has some errors (and it certainly does -
>> the one that's been just reported) the conn->mutex is locked again -
>> without any previous unlock:
> 
> ACK; bug introduced in commit ca0ea2a.

AHA! In that case this patch is incomplete as looking at the blamed
commit I've found another candidate worth fixing (even though I have not
experienced any deadlock in it yet): virConnectRegisterCloseCallback().

I've squashed this in prior to push:

diff --git a/src/libvirt.c b/src/libvirt.c
index 1f5590f..619da80 100644
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -20446,9 +20446,9 @@ virConnectRegisterCloseCallback(virConnectPtr conn,
     return 0;

 error:
-    virDispatchError(conn);
     virObjectUnlock(conn->closeCallback);
     virMutexUnlock(&conn->lock);
+    virDispatchError(conn);
     virObjectUnref(conn);
     return -1;
 }

Thanks!

Michal