Re: [Qemu-devel] [PATCH] cpu: Fix crash with empty -cpu option

[Igor Mammedov <imammedo@redhat.com>]

On Thu, 18 Apr 2019 00:45:01 -0300
Eduardo Habkost <ehabkost@redhat.com> wrote:

> Fix the following crash:
> 
>   $ qemu-system-x86_64 -cpu ''
>   qemu-system-x86_64: qom/cpu.c:291: cpu_class_by_name: \
>       Assertion `cpu_model && cc->class_by_name' failed.
> 
> Regression test script included.
> 
> Fixes: commit 99193d8f2ef5 ("cpu: drop unnecessary NULL check and cpu_common_class_by_name()")
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
>  exec.c                              |  4 ++++
>  tests/acceptance/empty_cpu_model.py | 19 +++++++++++++++++++
>  2 files changed, 23 insertions(+)
>  create mode 100644 tests/acceptance/empty_cpu_model.py
> 
> diff --git a/exec.c b/exec.c
> index 1ca95df9d8..d816b38863 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -999,6 +999,10 @@ const char *parse_cpu_option(MachineState *machine, const char *cpu_option)
>      const char *cpu_type;
>  
>      model_pieces = g_strsplit(cpu_option, ",", 2);
> +    if (!model_pieces[0]) {
> +        error_report("-cpu option cannot be empty");
> +        exit(1);

s/1/EXIT_FAILURE/

> +    }
>  
>      cc = lookup_cpu_class(model_pieces[0], &error_fatal);
>      cpu_type = object_class_get_name(OBJECT_CLASS(cc));
> diff --git a/tests/acceptance/empty_cpu_model.py b/tests/acceptance/empty_cpu_model.py
> new file mode 100644
> index 0000000000..3f4f663582
> --- /dev/null
> +++ b/tests/acceptance/empty_cpu_model.py
> @@ -0,0 +1,19 @@
> +# Check for crash when using empty -cpu option
> +#
> +# Copyright (c) 2019 Red Hat, Inc.
> +#
> +# Author:
> +#  Eduardo Habkost <ehabkost@redhat.com>
> +#
> +# This work is licensed under the terms of the GNU GPL, version 2 or
> +# later.  See the COPYING file in the top-level directory.
> +import subprocess
> +from avocado_qemu import Test
> +
> +class EmptyCPUModel(Test):
> +    def test(self):
> +        cmd = [self.qemu_bin, '-S', '-display', 'none', '-machine', 'none', '-cpu', '']
> +        r = subprocess.run(cmd, stderr=subprocess.PIPE, stdout=subprocess.PIPE)
> +        self.assertEquals(r.returncode, 1, "QEMU exit code should be 1")
> +        self.assertEquals(r.stdout, b'', "QEMU stdout should be empty")
> +        self.assertNotEquals(r.stderr, b'', "QEMU stderr shouldn't be empty")