Re: [Qemu-devel] [FIX PATCH] spapr_rtas: Prevent QEMU crash during hotplug without a prior device_add

[Michael Roth <mdroth@linux.vnet.ibm.com>]

Quoting Bharata B Rao (2015-08-25 23:04:11)
> If drmgr is used in the guest to hotplug a device before a device_add
> has been issued via the QEMU monitor, QEMU segfaults in configure_connector
> call. This occurs due to accessing of NULL FDT which otherwise would have
> been created and associated with the DRC during device_add command.
> 
> Check for NULL FDT and return failure from configure_connector call.
> 
> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
> Cc: Michael Roth <mdroth@linux.vnet.ibm.com>

Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>

> ---
> Not fully sure if RTAS_OUT_HW_ERROR is the right error code here. Should
> we be using RTAS_OUT_NOT_SUPPORTED instead ?
> 
>  hw/ppc/spapr_rtas.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> index e99e25f..3be8eec 100644
> --- a/hw/ppc/spapr_rtas.c
> +++ b/hw/ppc/spapr_rtas.c
> @@ -522,6 +522,12 @@ static void rtas_ibm_configure_connector(PowerPCCPU *cpu,
> 
>      drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
>      fdt = drck->get_fdt(drc, NULL);
> +    if (!fdt) {
> +        DPRINTF("rtas_ibm_configure_connector: Missing FDT for DRC index: %xh\n",
> +                drc_index);
> +        rc = RTAS_OUT_HW_ERROR;
> +        goto out;
> +    }
> 
>      ccs = spapr_ccs_find(spapr, drc_index);
>      if (!ccs) {
> -- 
> 2.1.0
>