Re: [PATCH] kunit: tool: stop using a shell to run kernel under QEMU

From: Brendan Higgins
Date: Wed May 11 2022 - 19:24:31 EST


On Wed, Apr 20, 2022 at 4:30 PM Daniel Latypov <dlatypov@xxxxxxxxxx> wrote:
>
> Note: this potentially breaks custom qemu_configs if people are using
> them! But the fix for them is simple, don't specify multiple arguments
> in one string and don't add on a redundant ''.
>
> It feels a bit iffy to be using a shell in the first place.
>
> There's the usual shenanigans where people could pass in arbitrary shell
> commands via --kernel_arg (since we're just adding '' around the
> kernel_cmdline) or via a custom qemu_config.
> This isn't too much of a concern given the nature of this script (and
> the qemu_config file is in python, you can do w/e you want already).
>
> But it does have some other drawbacks.
>
> One example of a kunit-specific pain point:
> If the relevant qemu binary is missing, we get output like this:
> > /bin/sh: line 1: qemu-system-aarch64: command not found
> This in turn results in our KTAP parser complaining about
> missing/invalid KTAP, but we don't directly show the error!
> It's even more annoying to debug when you consider --raw_output only
> shows KUnit output by default, i.e. you need --raw_output=all to see it.
>
> Whereas directly invoking the binary, Python will raise a
> FileNotFoundError for us, which is a noisier but more clear.
>
> Making this change requires
> * splitting parameters like ['-m 256'] into ['-m', '256'] in
> kunit/qemu_configs/*.py
> * change [''] to [] in kunit/qemu_configs/*.py since otherwise
> QEMU fails w/ 'Device needs media, but drive is empty'
> * dropping explicit quoting of the kernel cmdline
> * using shlex.quote() when we print what command we're running
> so the user can copy-paste and run it
>
> Signed-off-by: Daniel Latypov <dlatypov@xxxxxxxxxx>

One issue I noticed below, otherwise:

Reviewed-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx>

> ---
> tools/testing/kunit/kunit_kernel.py | 18 ++++++++++--------
> tools/testing/kunit/qemu_configs/alpha.py | 2 +-
> tools/testing/kunit/qemu_configs/arm.py | 2 +-
> tools/testing/kunit/qemu_configs/arm64.py | 2 +-
> tools/testing/kunit/qemu_configs/i386.py | 2 +-
> tools/testing/kunit/qemu_configs/powerpc.py | 2 +-
> tools/testing/kunit/qemu_configs/riscv.py | 6 +++---
> tools/testing/kunit/qemu_configs/s390.py | 4 ++--
> tools/testing/kunit/qemu_configs/sparc.py | 2 +-
> tools/testing/kunit/qemu_configs/x86_64.py | 2 +-
> 10 files changed, 22 insertions(+), 20 deletions(-)
>
> diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
> index 483f78e15ce9..1b9c4922a675 100644
> --- a/tools/testing/kunit/kunit_kernel.py
> +++ b/tools/testing/kunit/kunit_kernel.py
> @@ -11,6 +11,7 @@ import importlib.util
> import logging
> import subprocess
> import os
> +import shlex
> import shutil
> import signal
> import threading
> @@ -118,16 +119,17 @@ class LinuxSourceTreeOperationsQemu(LinuxSourceTreeOperations):
> '-nodefaults',
> '-m', '1024',
> '-kernel', kernel_path,
> - '-append', '\'' + ' '.join(params + [self._kernel_command_line]) + '\'',
> + '-append', ' '.join(params + [self._kernel_command_line]),
> '-no-reboot',
> '-nographic',
> - '-serial stdio'] + self._extra_qemu_params
> - print('Running tests with:\n$', ' '.join(qemu_command))
> - return subprocess.Popen(' '.join(qemu_command),
> - stdin=subprocess.PIPE,
> - stdout=subprocess.PIPE,
> - stderr=subprocess.STDOUT,
> - text=True, shell=True, errors='backslashreplace')
> + '-serial', 'stdio'] + self._extra_qemu_params
> + # Note: shlex.join() does what we want, but requires python 3.8+.
> + print('Running tests with:\n$', ' '.join(shlex.quote(arg) for arg in qemu_command))
> + return subprocess.Popen(qemu_command,
> + stdin=subprocess.PIPE,
> + stdout=subprocess.PIPE,
> + stderr=subprocess.STDOUT,
> + text=True, errors='backslashreplace')
>
> class LinuxSourceTreeOperationsUml(LinuxSourceTreeOperations):
> """An abstraction over command line operations performed on a source tree."""
> diff --git a/tools/testing/kunit/qemu_configs/alpha.py b/tools/testing/kunit/qemu_configs/alpha.py
> index 5d0c0cff03bd..3ac846e03a6b 100644
> --- a/tools/testing/kunit/qemu_configs/alpha.py
> +++ b/tools/testing/kunit/qemu_configs/alpha.py
> @@ -7,4 +7,4 @@ CONFIG_SERIAL_8250_CONSOLE=y''',
> qemu_arch='alpha',
> kernel_path='arch/alpha/boot/vmlinux',
> kernel_command_line='console=ttyS0',
> - extra_qemu_params=[''])
> + extra_qemu_params=[])
> diff --git a/tools/testing/kunit/qemu_configs/arm.py b/tools/testing/kunit/qemu_configs/arm.py
> index b9c2a35e0296..db2160200566 100644
> --- a/tools/testing/kunit/qemu_configs/arm.py
> +++ b/tools/testing/kunit/qemu_configs/arm.py
> @@ -10,4 +10,4 @@ CONFIG_SERIAL_AMBA_PL011_CONSOLE=y''',
> qemu_arch='arm',
> kernel_path='arch/arm/boot/zImage',
> kernel_command_line='console=ttyAMA0',
> - extra_qemu_params=['-machine virt'])
> + extra_qemu_params=['-machine', 'virt'])
> diff --git a/tools/testing/kunit/qemu_configs/arm64.py b/tools/testing/kunit/qemu_configs/arm64.py
> index 517c04459f47..67d04064f785 100644
> --- a/tools/testing/kunit/qemu_configs/arm64.py
> +++ b/tools/testing/kunit/qemu_configs/arm64.py
> @@ -9,4 +9,4 @@ CONFIG_SERIAL_AMBA_PL011_CONSOLE=y''',
> qemu_arch='aarch64',
> kernel_path='arch/arm64/boot/Image.gz',
> kernel_command_line='console=ttyAMA0',
> - extra_qemu_params=['-machine virt', '-cpu cortex-a57'])
> + extra_qemu_params=['-machine', 'virt', '-cpu', 'cortex-a57'])
> diff --git a/tools/testing/kunit/qemu_configs/i386.py b/tools/testing/kunit/qemu_configs/i386.py
> index aed3ffd3937d..52b80be40e4b 100644
> --- a/tools/testing/kunit/qemu_configs/i386.py
> +++ b/tools/testing/kunit/qemu_configs/i386.py
> @@ -7,4 +7,4 @@ CONFIG_SERIAL_8250_CONSOLE=y''',
> qemu_arch='x86_64',
> kernel_path='arch/x86/boot/bzImage',
> kernel_command_line='console=ttyS0',
> - extra_qemu_params=[''])
> + extra_qemu_params=[])
> diff --git a/tools/testing/kunit/qemu_configs/powerpc.py b/tools/testing/kunit/qemu_configs/powerpc.py
> index 35e9de24f0db..6c901149726b 100644
> --- a/tools/testing/kunit/qemu_configs/powerpc.py
> +++ b/tools/testing/kunit/qemu_configs/powerpc.py
> @@ -9,4 +9,4 @@ CONFIG_HVC_CONSOLE=y''',
> qemu_arch='ppc64',
> kernel_path='vmlinux',
> kernel_command_line='console=ttyS0',
> - extra_qemu_params=['-M pseries', '-cpu power8'])
> + extra_qemu_params=['-M', ' pseries', '-cpu', 'power8'])

This should be '-M', 'pseries', not '-M', ' pseries', (you left an
extra space in.

Note this actually breaks QEMU on my machine.

> diff --git a/tools/testing/kunit/qemu_configs/riscv.py b/tools/testing/kunit/qemu_configs/riscv.py
> index 9e528087cd7c..b882fde39435 100644
> --- a/tools/testing/kunit/qemu_configs/riscv.py
> +++ b/tools/testing/kunit/qemu_configs/riscv.py
> @@ -26,6 +26,6 @@ CONFIG_SERIAL_EARLYCON_RISCV_SBI=y''',
> kernel_path='arch/riscv/boot/Image',
> kernel_command_line='console=ttyS0',
> extra_qemu_params=[
> - '-machine virt',
> - '-cpu rv64',
> - '-bios opensbi-riscv64-generic-fw_dynamic.bin'])
> + '-machine', 'virt',
> + '-cpu', 'rv64',
> + '-bios', 'opensbi-riscv64-generic-fw_dynamic.bin'])
> diff --git a/tools/testing/kunit/qemu_configs/s390.py b/tools/testing/kunit/qemu_configs/s390.py
> index e310bd521113..98fa4fb60c0a 100644
> --- a/tools/testing/kunit/qemu_configs/s390.py
> +++ b/tools/testing/kunit/qemu_configs/s390.py
> @@ -10,5 +10,5 @@ CONFIG_MODULES=y''',
> kernel_path='arch/s390/boot/bzImage',
> kernel_command_line='console=ttyS0',
> extra_qemu_params=[
> - '-machine s390-ccw-virtio',
> - '-cpu qemu',])
> + '-machine', 's390-ccw-virtio',
> + '-cpu', 'qemu',])
> diff --git a/tools/testing/kunit/qemu_configs/sparc.py b/tools/testing/kunit/qemu_configs/sparc.py
> index 27f474e7ad6e..e975c4331a7c 100644
> --- a/tools/testing/kunit/qemu_configs/sparc.py
> +++ b/tools/testing/kunit/qemu_configs/sparc.py
> @@ -7,4 +7,4 @@ CONFIG_SERIAL_8250_CONSOLE=y''',
> qemu_arch='sparc',
> kernel_path='arch/sparc/boot/zImage',
> kernel_command_line='console=ttyS0 mem=256M',
> - extra_qemu_params=['-m 256'])
> + extra_qemu_params=['-m', '256'])
> diff --git a/tools/testing/kunit/qemu_configs/x86_64.py b/tools/testing/kunit/qemu_configs/x86_64.py
> index 77ab1aeee8a3..dc7949076863 100644
> --- a/tools/testing/kunit/qemu_configs/x86_64.py
> +++ b/tools/testing/kunit/qemu_configs/x86_64.py
> @@ -7,4 +7,4 @@ CONFIG_SERIAL_8250_CONSOLE=y''',
> qemu_arch='x86_64',
> kernel_path='arch/x86/boot/bzImage',
> kernel_command_line='console=ttyS0',
> - extra_qemu_params=[''])
> + extra_qemu_params=[])
>
> base-commit: 59729170afcd4900e08997a482467ffda8d88c7f
> --
> 2.36.0.rc0.470.gd361397f0d-goog
>