On Wed, Sep 16, 2015 at 07:29:17PM -0500, Suman Anna wrote:
> The virtio core uses a static ida named virtio_index_ida for
> assigning index numbers to virtio devices during registration.
> The ida core may allocate some internal idr cache layers and
> an ida bitmap upon any ida allocation, and all these layers are
> truely freed only upon the ida destruction. The virtio_index_ida
> is not destroyed at present, leading to a memory leak when using
> the virtio core as a module and atleast one virtio device is
> registered and unregistered.
>
> Fix this by invoking ida_destroy() in the virtio core module
> exit.
>
> Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
> Signed-off-by: Suman Anna <s-anna@xxxxxx>
Interesting.
Will the same apply to e.g. sd_index_ida in drivers/scsi/sd.c
or iscsi_sess_ida in drivers/scsi/scsi_transport_iscsi.c?
If no, why not?
One doesn't generally expect to have to free global variables.
Maybe we should forbid DEFINE_IDA in modules?
James, could you comment on this please?
> ---
> drivers/virtio/virtio.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
> index b1877d73fa56..7062bb0975a5 100644
> --- a/drivers/virtio/virtio.c
> +++ b/drivers/virtio/virtio.c
> @@ -412,6 +412,7 @@ static int virtio_init(void)
> static void __exit virtio_exit(void)
> {
> bus_unregister(&virtio_bus);
> + ida_destroy(&virtio_index_ida);
> }
> core_initcall(virtio_init);
> module_exit(virtio_exit);
> --
> 2.5.0
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