Re: [PATCH] target/i386: Check NULL monitor pointer when injecting MCE

[Philippe Mathieu-Daudé]

Hi Tao,

On 20/3/24 07:02, Markus Armbruster wrote:
> Tao Su <tao1.su@linux.intel.com> writes:
>
> > monitor_puts() doesn't check the monitor pointer, but do_inject_x86_mce()
> > may have a parameter with NULL monitor pointer. Check the monitor pointer
> > before calling monitor_puts().
> >
> > Fixes: bf0c50d4aa85 (monitor: expose monitor_puts to rest of code)
> > Reviwed-by: Xiaoyao Li <xiaoyao.li@intel.com>
> > Signed-off-by: Tao Su <tao1.su@linux.intel.com>
> > ---
> >   target/i386/helper.c | 3 ++-
> >   1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/target/i386/helper.c b/target/i386/helper.c
> > index 2070dd0dda..a9ff830a17 100644
> > --- a/target/i386/helper.c
> > +++ b/target/i386/helper.c
> > @@ -430,7 +430,8 @@ static void do_inject_x86_mce(CPUState *cs, run_on_cpu_data 
> > data)
> >           if (need_reset) {
> >               emit_guest_memory_failure(MEMORY_FAILURE_ACTION_RESET, ar,
> >                                         recursive);
> > -            monitor_puts(params->mon, msg);
> > +            if (params->mon)

Missing braces, see QEMU coding style:
https://www.qemu.org/docs/master/devel/style.html#block-structure

> > +                monitor_puts(params->mon, msg);
> >               qemu_log_mask(CPU_LOG_RESET, "%s\n", msg);
> >               qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
> >               return;
>
> Could instead revert the broken part of commit bf0c50d4aa85:
>
>    -            monitor_puts(params->mon, msg);
>    +            monitor_printf(params->mon, "%s", msg);
>                 qemu_log_mask(CPU_LOG_RESET, "%s\n", msg);
>
> Then the fact that we send the same message to monitor and log is again
> more obvious.
>
> Either way:
> Reviewed-by: Markus Armbruster <armbru@redhat.com>