[libvirt] [PATCH v3 0/2] vbox: address thread-safety issues

[John Ferlan]

On 11/23/2016 02:01 PM, Dawid Zamirski wrote:
> This patch series solves vbox driver thread-safety issues where
> libvird process would segfault when there was more than one concurrent
> vbox connection. The reason for the segfault was because the original
> implementation called pfnComInitialize/Unintialize on each
> virConnectOpen/Close calls which were setting pointers to ISession and
> IVirtualBox instances that were held by the global g_pVBoxGlobalData.
> This caused new connection to overwrite the pointer created by the
> prior connection.
> 
> Changes since v2 to address feedback in [1]:
> 
> * call uninitialize when vboxSdkInitialize or vboxExtractVersion fails.
> * make sure to set the global vbox_driver pointer to NULL after 
>   virObjectUnref releases last  reference, to avoid segfaults when
>   VBOX_RELEASE is called in unintialize call.
> * tested all possible failure paths to make sure libvirtd does not
>   crash, that is, vboxSdkInitialize has 4 code paths that can possibly
>   return -1 and made sure all of them are safely handled.
> * fixed "unintilalize" typos in code comments and commit messages.
> 
> In other words, the change boils down to:
> 
> if (vboxSdkInitialize() < 0 || vboxExtractVersion() < 0) {
>     gVBoxAPI.UPFN.Uninitialize(vbox_driver); // call uninit on failure
>     /* make sure to clear the pointer when last reference was released */
>     if (!virObjectUnref(vbox_driver))
>         vbox_driver = NULL; // make sure this is NULL
> 
>     virMutexUnlock(&vbox_driver_lock);
> 
>     return NULL;
> }
> 
> [1] https://www.redhat.com/archives/libvir-list/2016-November/msg01132.html
> 
> Dawid Zamirski (2):
>   vbox: change how vbox API is initialized.
>   vbox: get rid of g_pVBoxGlobalData
> 
>  src/vbox/vbox_common.c        | 565 +++++++++++++++++++++++-------------------
>  src/vbox/vbox_common.h        |   2 +-
>  src/vbox/vbox_driver.c        |   1 +
>  src/vbox/vbox_network.c       |  24 +-
>  src/vbox/vbox_storage.c       |  20 +-
>  src/vbox/vbox_tmpl.c          | 434 ++++++++++++++++----------------
>  src/vbox/vbox_uniformed_api.h | 110 ++++----
>  7 files changed, 616 insertions(+), 540 deletions(-)
> 

ACK series (and pushed) with an adjustment to news.html.in
"Improvements" section to list "vbox: Address thread safety issues"

John