Re: [Qemu-ppc] [Qemu-devel] [PATCH qemu] xics-kvm: Fix compile warning

[Markus Armbruster]

Alexey Kardashevskiy <address@hidden> writes:

> This fixes uninitialized variable warning:
>
> /home/aik/p/qemu/hw/intc/xics_kvm.c: In function ‘ics_set_kvm_state’:
> /home/aik/p/qemu/hw/intc/xics_kvm.c:281:20: warning: ‘ret’ may be used 
> uninitialized in this function [-Wmaybe-uninitialized]
>              return ret;
>                     ^~~
>
> Discovered with gcc (Ubuntu 7.3.0-16ubuntu3) 7.3.0 from Ubuntu 18.04.
>
> Fixes: bf358b541b8 "xics_kvm: use KVM helpers"
> Signed-off-by: Alexey Kardashevskiy <address@hidden>
> ---
>  hw/intc/xics_kvm.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/hw/intc/xics_kvm.c b/hw/intc/xics_kvm.c
> index 8bdf6af..48efbce 100644
> --- a/hw/intc/xics_kvm.c
> +++ b/hw/intc/xics_kvm.c
> @@ -273,8 +273,8 @@ static int ics_set_kvm_state(ICSState *ics, int 
> version_id)
>                  state |= KVM_XICS_QUEUED;
>          }
>  
> -        kvm_device_access(kernel_xics_fd, KVM_DEV_XICS_GRP_SOURCES,
> -                          i + ics->offset, &state, true, &local_err);
> +        ret = kvm_device_access(kernel_xics_fd, KVM_DEV_XICS_GRP_SOURCES,
> +                                i + ics->offset, &state, true, &local_err);
>          if (local_err) {
>              error_report("Unable to restore KVM interrupt controller state"
>                      " for IRQs %d: %s", i + ics->offset, strerror(errno));
               return ret;
           }

Unless all callers effectively ignore the return value, this fixes a
bug, not just a compiler warning.  Recommend to check callers to find
the bug's impact, and document it in your commit message.

Messed up in commit bf358b541b8.  Would be nice to mention that in your
commit message.

Also messed up there: leaks local_err.  Please fix that, too.