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@xxxxxxxxxx> > --- > 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@xxxxxxxxxxxxxxx > S: Maintained > F: drivers/mmc/host/sdhci-pci-dwc-mshc.c > > +SYSFS TEST DRIVER > +M: Luis Chamberlain <mcgrof@xxxxxxxxxx> > +L: linux-kernel@xxxxxxxxxxxxxxx > +S: Maintained > +F: lib/test_sysfs.c > +F: tools/testing/selftests/sysfs/ > + > SYSTEM CONFIGURATION (SYSCON) > M: Lee Jones <lee.jones@xxxxxxxxxx> > M: Arnd Bergmann <arnd@xxxxxxxx> > 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
