Re: [Qemu-devel] [Qemu-block] [PATCH for-3.1] blockdev: Consistently use snapshot_node_name in external_snapshot_prepare()

[Alberto Garcia <berto@igalia.com>]

On Thu 01 Nov 2018 05:30:37 PM CET, Peter Maydell wrote:
> In the function external_snapshot_prepare() we have a
> BlockdevSnapshotSync struct, which has the usual combination
> of has_snapshot_node_name and snapshot_node_name fields for an
> optional field. We set up a local variable
>         const char *snapshot_node_name =
>             s->has_snapshot_node_name ? s->snapshot_node_name : NULL;
>
> and then mostly use "if (!snapshot_node_name)" for checking
> whether we have a snapshot node name. The exception is that in
> one place we check s->has_snapshot_node_name instead. This
> confuses Coverity (CID 1396473), which thinks it might be
> possible to get here with s->has_snapshot_node_name true but
> snapshot_node_name NULL, and warns that the call to
> qdict_put_str() will segfault in that case.
>
> Make the code consistent and unconfuse Coverity by using
> the same check for this conditional that we do in the rest
> of the surrounding code.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Alberto Garcia <berto@igalia.com>

Berto