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SubjectRe: [PATCH v2 1/4] selftests: add tests_sysfs module
On Fri, Jul 02, 2021 at 05:46:29PM -0700, Luis Chamberlain wrote:
> This adds a new selftest module which can be used to test sysfs, which
> would otherwise require using an existing driver. This lets us muck
> with a template driver to test breaking things without affecting
> system behaviour or requiring the dependencies of a real device
> driver.
>
> A series of 28 tests are added. Support for using two device types are
> supported:
>
> * misc
> * block
>
> Contrary to sysctls, sysfs requires a full write to happen at once, and
> so we reduce the digit tests to single writes. Two main sysfs knobs are
> provided for testing reading/storing, one which doesn't inclur any
> delays and another which can incur programmed delays. What locks are
> held, if any, are configurable, at module load time, or through dynamic
> configuration at run time.
>
> Since sysfs is a technically filesystem, but a pseudo one, which
> requires a kernel user, our test_sysfs module and respective test script
> embraces fstests format for tests in the kernel ring bufffer. Likewise,
> a scraper for kernel crashes is provided which matches what fstests does
> as well.
>
> Two tests are kept disabled as they currently cause a deadlock, and so
> this provides a mechanism to easily show proof and demo how the deadlock
> can happen:
>
> Demos the deadlock with a device specific lock
> ./tools/testing/selftests/sysfs/sysfs.sh -t 0027
>
> Demos the deadlock with rtnl_lock()
> ./tools/testing/selftests/sysfs/sysfs.sh -t 0028
>
> Two separate solutions to the deadlock issue have been proposed,
> and so now its a matter of either documenting this limitation or
> eventually adopting a generic fix.
>
> This selftests will shortly be expanded upon with more tests which
> require further kernel changes in order to provide better test
> coverage.

Why is this not using kunit? We should not be adding new in-kernel
tests that are not using that api anymore.

>
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
> MAINTAINERS | 7 +
> lib/Kconfig.debug | 10 +
> lib/Makefile | 1 +
> lib/test_sysfs.c | 943 +++++++++++++++++++
> tools/testing/selftests/sysfs/Makefile | 12 +
> tools/testing/selftests/sysfs/config | 2 +
> tools/testing/selftests/sysfs/sysfs.sh | 1202 ++++++++++++++++++++++++
> 7 files changed, 2177 insertions(+)
> create mode 100644 lib/test_sysfs.c
> create mode 100644 tools/testing/selftests/sysfs/Makefile
> create mode 100644 tools/testing/selftests/sysfs/config
> create mode 100755 tools/testing/selftests/sysfs/sysfs.sh
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 66d047dc6880..fd369ed50040 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -17958,6 +17958,13 @@ L: linux-mmc@vger.kernel.org
> S: Maintained
> F: drivers/mmc/host/sdhci-pci-dwc-mshc.c
>
> +SYSFS TEST DRIVER
> +M: Luis Chamberlain <mcgrof@kernel.org>
> +L: linux-kernel@vger.kernel.org
> +S: Maintained
> +F: lib/test_sysfs.c
> +F: tools/testing/selftests/sysfs/
> +
> SYSTEM CONFIGURATION (SYSCON)
> M: Lee Jones <lee.jones@linaro.org>
> M: Arnd Bergmann <arnd@arndb.de>
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index fb370c7c4756..568838ac1189 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -2360,6 +2360,16 @@ config TEST_SYSCTL
>
> If unsure, say N.
>
> +config TEST_SYSFS
> + tristate "sysfs test driver"
> + depends on SYSFS
> + help
> + This builds the "test_sysfs" module. This driver enables to test the
> + sysfs file system safely without affecting production knobs which
> + might alter system functionality.
> +
> + If unsure, say N.
> +
> config BITFIELD_KUNIT
> tristate "KUnit test bitfield functions at runtime"
> depends on KUNIT
> diff --git a/lib/Makefile b/lib/Makefile
> index 5efd1b435a37..effd1ef806f0 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -61,6 +61,7 @@ obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o
> obj-$(CONFIG_TEST_BITOPS) += test_bitops.o
> CFLAGS_test_bitops.o += -Werror
> obj-$(CONFIG_TEST_SYSCTL) += test_sysctl.o
> +obj-$(CONFIG_TEST_SYSFS) += test_sysfs.o
> obj-$(CONFIG_TEST_HASH) += test_hash.o test_siphash.o
> obj-$(CONFIG_TEST_IDA) += test_ida.o
> obj-$(CONFIG_KASAN_KUNIT_TEST) += test_kasan.o
> diff --git a/lib/test_sysfs.c b/lib/test_sysfs.c
> new file mode 100644
> index 000000000000..bf43016d40b5
> --- /dev/null
> +++ b/lib/test_sysfs.c
> @@ -0,0 +1,943 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later

This does not match your "boiler-plate" text below, sorry.

thanks,

greg k-h

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