[libvirt] [PATCH] qemu: Free previous error

[Daniel P. Berrange]

On Mon, Jul 11, 2011 at 07:02:35PM +0200, Michal Privoznik wrote:
> virCopyLastError simply overwrites destination, which may lead to leak
> if there already was error. Therefore we need first to free destination.
> ---
>  src/qemu/qemu_migration.c |    1 +
>  src/qemu/qemu_monitor.c   |    1 +
>  2 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
> index 3e4f4fe..56dd26b 100644
> --- a/src/qemu/qemu_migration.c
> +++ b/src/qemu/qemu_migration.c
> @@ -1586,6 +1586,7 @@ static void qemuMigrationIOFunc(void *arg)
>      return;
>  
>  error:
> +    virResetError(&data->err);
>      virCopyLastError(&data->err);
>      virResetLastError();
>  }
> diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
> index 8573262..66a4e48 100644
> --- a/src/qemu/qemu_monitor.c
> +++ b/src/qemu/qemu_monitor.c
> @@ -603,6 +603,7 @@ qemuMonitorIO(int watch, int fd, int events, void *opaque) {
>              if (!err)
>                  qemuReportError(VIR_ERR_INTERNAL_ERROR,
>                                  _("Error while processing monitor IO"));
> +            virResetError(&mon->lastError);
>              virCopyLastError(&mon->lastError);
>              virResetLastError();
>          }

NACK, neither of these are required.

There is only one place in qemuMigrationIOFunc which sets data->err
and that is the one you're modifying. So it is impossible for data->err
to have an existing error.

The code changed in qemuMonitorIO has already validated that mon->lastError
is not set in an if(...) that the diff here doesn't show.

Daniel
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