Re: [Qemu-devel] [PATCH 14/31] numa: Fix QMP command set-numa-node error handling

[Igor Mammedov <imammedo@redhat.com>]

On Mon,  8 Oct 2018 19:31:08 +0200
Markus Armbruster <armbru@redhat.com> wrote:

> Calling error_report() in a function that takes an Error ** argument
> is suspicious.  parse_numa_node() does that, and then exit()s.  It
> also passes &error_fatal to machine_set_cpu_numa_node().  Both wrong.
> Attempting to configure numa when the machine doesn't support it kills
> the VM:
> 
>     $ qemu-system-x86_64 -nodefaults -S -display none -M none -preconfig -qmp stdio
>     {"QMP": {"version": {"qemu": {"micro": 50, "minor": 0, "major": 3}, "package": "v3.0.0-837-gc5e4e49258"}, "capabilities": []}}
>     {"execute": "qmp_capabilities"}
>     {"return": {}}
>     {"execute": "set-numa-node", "arguments": {"type": "node"}}
>     NUMA is not supported by this machine-type
>     $ echo $?
>     1
> 
> Messed up when commit 64c2a8f6d3f and 7c88e65d9e9 (v2.10.0) added
> incorrect error handling right next to correct examples.  Latent bug
> until commit f3be67812c2 (v3.0.0) made it accessible via QMP.  Fairly
> harmless in practice, because it's limited to RUN_STATE_PRECONFIG.
> The fix is obvious: replace error_report(); exit() by error_setg();
> return.
> 
> This affects parse_numa_node()'s other caller
> numa_complete_configuration(): since it ignores errors, the "NUMA is
> not supported by this machine-type" is now ignored, too.  But that
> error is as unexpected there as any other.  Change it to abort on
> error instead.
> 
> Fixes: f3be67812c226162f86ce92634bd913714445420
> Cc: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> 
> fixup! numa: Fix QMP command set-numa-node error handling
> ---
>  numa.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/numa.c b/numa.c
> index 81542d4ebb..1d7c49ad43 100644
> --- a/numa.c
> +++ b/numa.c
> @@ -60,6 +60,7 @@ NodeInfo numa_info[MAX_NODES];
>  static void parse_numa_node(MachineState *ms, NumaNodeOptions *node,
>                              Error **errp)
>  {
> +    Error *err = NULL;
>      uint16_t nodenr;
>      uint16List *cpus = NULL;
>      MachineClass *mc = MACHINE_GET_CLASS(ms);
> @@ -82,8 +83,8 @@ static void parse_numa_node(MachineState *ms, NumaNodeOptions *node,
>      }
>  
>      if (!mc->cpu_index_to_instance_props || !mc->get_default_cpu_node_id) {
> -        error_report("NUMA is not supported by this machine-type");
> -        exit(1);
> +        error_setg(errp, "NUMA is not supported by this machine-type");
> +        return;
>      }
>      for (cpus = node->cpus; cpus; cpus = cpus->next) {
>          CpuInstanceProperties props;
> @@ -97,7 +98,11 @@ static void parse_numa_node(MachineState *ms, NumaNodeOptions *node,
>          props = mc->cpu_index_to_instance_props(ms, cpus->value);
>          props.node_id = nodenr;
>          props.has_node_id = true;
> -        machine_set_cpu_numa_node(ms, &props, &error_fatal);
> +        machine_set_cpu_numa_node(ms, &props, &err);
> +        if (err) {
> +            error_propagate(errp, err);
> +            return;
> +        }
>      }
>  
>      if (node->has_mem && node->has_memdev) {
> @@ -367,7 +372,7 @@ void numa_complete_configuration(MachineState *ms)
>      if (ms->ram_slots > 0 && nb_numa_nodes == 0 &&
>          mc->auto_enable_numa_with_memhp) {
>              NumaNodeOptions node = { };
> -            parse_numa_node(ms, &node, NULL);
> +            parse_numa_node(ms, &node, &error_abort);
it won't affect machines with numa support /i.e. no change/,
but if machine that doesn't support numa, gets here it fine for it to die.

>      }
>  
>      assert(max_numa_nodeid <= MAX_NODES);

Reviewed-by: Igor Mammedov <imammedo@redhat.com>