Re: [Qemu-devel] [PATCH 2/2] target/i386/monitor.c: check return value of mon_get_cpu before using it

[Philippe Mathieu-Daudé]

On 02/17/2017 05:27 AM, Ziyue Yang wrote:
> From: Ziyue Yang <address@hidden>
>
> This patch eliminates the segfault caused by accessing CPU that doesn't
> exist in hmp command "info lapic", which can be reproduced by
>
> $ qemu-system-x86_64 -nographic -M none -serial none -monitor stdio
>
> and then type "info lapic" into qemu monitor.
>
> Signed-off-by: Ziyue Yang <address@hidden>

Reviewed-by: Philippe Mathieu-Daudé <address@hidden>

> ---
>  target/i386/monitor.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/target/i386/monitor.c b/target/i386/monitor.c
> index 468aa073bc..7b96c74a24 100644
> --- a/target/i386/monitor.c
> +++ b/target/i386/monitor.c
> @@ -624,8 +624,11 @@ const MonitorDef *target_monitor_defs(void)
>
>  void hmp_info_local_apic(Monitor *mon, const QDict *qdict)
>  {
> -    x86_cpu_dump_local_apic_state(mon_get_cpu(), (FILE *)mon, monitor_fprintf,
> -                                  CPU_DUMP_FPU);
> +    CPUState *cs = mon_get_cpu();
> +    if (cs) {
> +        x86_cpu_dump_local_apic_state(cs, (FILE *)mon, monitor_fprintf,
> +                                      CPU_DUMP_FPU);
> +    }
>  }
>
>  void hmp_info_io_apic(Monitor *mon, const QDict *qdict)