| Message ID | 20220810234056.2494993-1-npache@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | kunit: fix Kconfig for build-in tests USB4 and Nitro Enclaves | expand |
On Thu, Aug 11, 2022 at 7:41 AM Nico Pache <npache@redhat.com> wrote: > > Both the USB4 and Nitro Enclaves KUNIT tests are now able to be compiled > if KUNIT is compiled as a module. This leads to issues if KUNIT is being > packaged separately from the core kernel and when KUNIT is run baremetal > without the required driver compiled into the kernel. > > Fixes: 635dcd16844b ("thunderbolt: test: Use kunit_test_suite() macro") > Fixes: fe5be808fa6c ("nitro_enclaves: test: Use kunit_test_suite() macro") > Signed-off-by: Nico Pache <npache@redhat.com> > --- Hmm... I'm not quite sure I understand the case that's broken here. Is it: - KUnit is built as a module (CONFIG_KUNIT=m) - USB4/nitro_enclaves are also built as modules, with the test enabled. - The kunit module is not available at runtime, so neither driver module can load (due to missing kunit dependencies) If so, that's not a case (i.e., the kunit.ko module being unavailable if it was built) we've tried to support thus far. I guess a de-facto rule for supporting it would be to depend on KUNIT=y for any KUnit tests which are built into the same module as the driver they're testing. Alternatively, maybe we could do some horrible hacks to compile stub versions of various KUnit assertion symbols in unconditionally, which forward to the real ones if KUnit is available. (Personally, I'd love it if we could get rid of CONFIG_KUNIT=m altogether, and it's actually broken right at the moment[1]. There are still some cases (unloading / reloading KUnit with different filter options) which require it, though.) Cheers, -- David [1]: https://patchwork.kernel.org/project/linux-kselftest/patch/20220713005221.1926290-1-davidgow@google.com/ > drivers/thunderbolt/Kconfig | 3 +-- > drivers/virt/nitro_enclaves/Kconfig | 2 +- > 2 files changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/thunderbolt/Kconfig b/drivers/thunderbolt/Kconfig > index e76a6c173637..f12d0a3ee3e2 100644 > --- a/drivers/thunderbolt/Kconfig > +++ b/drivers/thunderbolt/Kconfig > @@ -29,8 +29,7 @@ config USB4_DEBUGFS_WRITE > > config USB4_KUNIT_TEST > bool "KUnit tests" if !KUNIT_ALL_TESTS > - depends on (USB4=m || KUNIT=y) > - depends on KUNIT > + depends on USB4 && KUNIT=y This can probably just: depends on KUNIT=y > default KUNIT_ALL_TESTS > > config USB4_DMA_TEST > diff --git a/drivers/virt/nitro_enclaves/Kconfig b/drivers/virt/nitro_enclaves/Kconfig > index ce91add81401..dc4d25c26256 100644 > --- a/drivers/virt/nitro_enclaves/Kconfig > +++ b/drivers/virt/nitro_enclaves/Kconfig > @@ -17,7 +17,7 @@ config NITRO_ENCLAVES > > config NITRO_ENCLAVES_MISC_DEV_TEST > bool "Tests for the misc device functionality of the Nitro Enclaves" if !KUNIT_ALL_TESTS > - depends on NITRO_ENCLAVES && KUNIT > + depends on NITRO_ENCLAVES && KUNIT=y > default KUNIT_ALL_TESTS > help > Enable KUnit tests for the misc device functionality of the Nitro > -- > 2.36.1 >
On Wed, Aug 10, 2022 at 8:20 PM David Gow <davidgow@google.com> wrote: > > On Thu, Aug 11, 2022 at 7:41 AM Nico Pache <npache@redhat.com> wrote: > > > > Both the USB4 and Nitro Enclaves KUNIT tests are now able to be compiled > > if KUNIT is compiled as a module. This leads to issues if KUNIT is being > > packaged separately from the core kernel and when KUNIT is run baremetal > > without the required driver compiled into the kernel. > > > > Fixes: 635dcd16844b ("thunderbolt: test: Use kunit_test_suite() macro") > > Fixes: fe5be808fa6c ("nitro_enclaves: test: Use kunit_test_suite() macro") > > Signed-off-by: Nico Pache <npache@redhat.com> > > --- > > Hmm... I'm not quite sure I understand the case that's broken here. Is it: > - KUnit is built as a module (CONFIG_KUNIT=m) > - USB4/nitro_enclaves are also built as modules, with the test enabled. > - The kunit module is not available at runtime, so neither driver > module can load (due to missing kunit dependencies) Exactly, except the issue is also when the USB/NE=y not just when they are modules. This is currently creating an issue with our build system during the depmod stage and has been preventing us from generating Fedora builds. > > If so, that's not a case (i.e., the kunit.ko module being unavailable > if it was built) we've tried to support thus far. I guess a de-facto > rule for supporting it would be to depend on KUNIT=y for any KUnit > tests which are built into the same module as the driver they're > testing. Yeah, although it's not been a case you've been trying to support, it has been working so far :) This has been the case (built-in tests utilizing 'depends on KUNIT=y') since we began supporting KUNIT in our testing infrastructure and it would be nice to keep that as a de-facto rule :) > > Alternatively, maybe we could do some horrible hacks to compile stub > versions of various KUnit assertion symbols in unconditionally, which > forward to the real ones if KUnit is available. > > (Personally, I'd love it if we could get rid of CONFIG_KUNIT=m > altogether, and it's actually broken right at the moment[1]. There are > still some cases (unloading / reloading KUnit with different filter > options) which require it, though.) Personally I'd hate to see KUNIT=m go as that is how we have been able to support running Kunit tests so far. A little background on how we utilize Kunit. We build with KUNIT=m and KUNIT_ALL_TESTS=m and run the tests baremetal. Our build system creates 3 packages (kernel, kernel-modules, and kernel-modules-internal), this allows us to ship the kernel and its modules, while also isolating packages that we dont want to ship outside of QE and developers. We then have our own infrastructure in place to run and collect the output of these tests in our pipelined environments. We dont utilize UML because we dont support that feature in RHEL. Fedora uses this same methodology for running KUNIT, so we are frequently running kunit on an 'upstream' variant. I'm not sure how many organizations are supporting continuous KUNIT testing, or how they are achieving it, but dropping module support would prevent us from doing the CI testing we have in place. Cheers! -- Nico > > Cheers, > -- David > > [1]: https://patchwork.kernel.org/project/linux-kselftest/patch/20220713005221.1926290-1-davidgow@google.com/ > > > drivers/thunderbolt/Kconfig | 3 +-- > > drivers/virt/nitro_enclaves/Kconfig | 2 +- > > 2 files changed, 2 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/thunderbolt/Kconfig b/drivers/thunderbolt/Kconfig > > index e76a6c173637..f12d0a3ee3e2 100644 > > --- a/drivers/thunderbolt/Kconfig > > +++ b/drivers/thunderbolt/Kconfig > > @@ -29,8 +29,7 @@ config USB4_DEBUGFS_WRITE > > > > config USB4_KUNIT_TEST > > bool "KUnit tests" if !KUNIT_ALL_TESTS > > - depends on (USB4=m || KUNIT=y) > > - depends on KUNIT > > + depends on USB4 && KUNIT=y > > This can probably just: > depends on KUNIT=y > > > > default KUNIT_ALL_TESTS > > > > config USB4_DMA_TEST > > diff --git a/drivers/virt/nitro_enclaves/Kconfig b/drivers/virt/nitro_enclaves/Kconfig > > index ce91add81401..dc4d25c26256 100644 > > --- a/drivers/virt/nitro_enclaves/Kconfig > > +++ b/drivers/virt/nitro_enclaves/Kconfig > > @@ -17,7 +17,7 @@ config NITRO_ENCLAVES > > > > config NITRO_ENCLAVES_MISC_DEV_TEST > > bool "Tests for the misc device functionality of the Nitro Enclaves" if !KUNIT_ALL_TESTS > > - depends on NITRO_ENCLAVES && KUNIT > > + depends on NITRO_ENCLAVES && KUNIT=y > > default KUNIT_ALL_TESTS > > help > > Enable KUnit tests for the misc device functionality of the Nitro > > -- > > 2.36.1 > > >
(+joefradley@google.com to comment on what Android is doing here) On Thu, Aug 11, 2022 at 8:44 PM Nico Pache <npache@redhat.com> wrote: > > On Wed, Aug 10, 2022 at 8:20 PM David Gow <davidgow@google.com> wrote: > > > > On Thu, Aug 11, 2022 at 7:41 AM Nico Pache <npache@redhat.com> wrote: > > > > > > Both the USB4 and Nitro Enclaves KUNIT tests are now able to be compiled > > > if KUNIT is compiled as a module. This leads to issues if KUNIT is being > > > packaged separately from the core kernel and when KUNIT is run baremetal > > > without the required driver compiled into the kernel. > > > > > > Fixes: 635dcd16844b ("thunderbolt: test: Use kunit_test_suite() macro") > > > Fixes: fe5be808fa6c ("nitro_enclaves: test: Use kunit_test_suite() macro") > > > Signed-off-by: Nico Pache <npache@redhat.com> > > > --- > > > > Hmm... I'm not quite sure I understand the case that's broken here. Is it: > > - KUnit is built as a module (CONFIG_KUNIT=m) > > - USB4/nitro_enclaves are also built as modules, with the test enabled. > > - The kunit module is not available at runtime, so neither driver > > module can load (due to missing kunit dependencies) > Exactly, except the issue is also when the USB/NE=y not just when they > are modules. This is currently creating an issue with our build system > during the depmod stage and has been preventing us from generating > Fedora builds. . Yeah: there's a nasty tradeoff here in that having these depend on KUNIT=y does (obviously) mean that it's not possible to run these tests with KUNIT=m. I'd agree that being able to ruin some tests is better than none, but there are quite a lot of tests which are doing the same sort of tricks as USB4/nitro_enclaves to embed tests in the same module as the code being tested. In particular, I think apparmor is doing something similar, and the incoming AMDGPU tests also build all of the tests into amdgpu.ko. If we require KUNIT=y for these, we're leaving a lot of tests on the table for KUNIT=m cases, which would otherwise work. The ideal solution would be to split the tests for these systems out into their own separate modules, but that's often quite tricky due to the sheer number of otherwise internal symbols which need exporting. > > > > If so, that's not a case (i.e., the kunit.ko module being unavailable > > if it was built) we've tried to support thus far. I guess a de-facto > > rule for supporting it would be to depend on KUNIT=y for any KUnit > > tests which are built into the same module as the driver they're > > testing. > Yeah, although it's not been a case you've been trying to support, it > has been working so far :) This has been the case (built-in tests > utilizing 'depends on KUNIT=y') since we began supporting KUNIT in our > testing infrastructure and it would be nice to keep that as a de-facto > rule :) Okay: let's try to stick with that for now, then (unless there are any objections from the people working on those particular tests), and look to either reinstate it if we find a better way of dealing with the missing/disabled kunit.ko case, or the tests can be split into a separate module. Personally, I don't expect we'll get either of those working in the short-term, but it's definitely a problem we'll have to confront more eventually. In the meantime, I think the KUnit position on this will be to note this as a consequence of building KUnit tests into bigger modules, and leave the final decision up to the maintainers of those subsystems/tests. This may result in there being some tests you have to explicitly disable (rather than being able to use KUNIT_ALL_TESTS) if an important module decides that they really want their tests to run when KUNIT=m (which may not happen, we'll see...) > > > > Alternatively, maybe we could do some horrible hacks to compile stub > > versions of various KUnit assertion symbols in unconditionally, which > > forward to the real ones if KUnit is available. > > > > (Personally, I'd love it if we could get rid of CONFIG_KUNIT=m > > altogether, and it's actually broken right at the moment[1]. There are > > still some cases (unloading / reloading KUnit with different filter > > options) which require it, though.) > Personally I'd hate to see KUNIT=m go as that is how we have been able > to support running Kunit tests so far. > > A little background on how we utilize Kunit. We build with KUNIT=m and > KUNIT_ALL_TESTS=m and run the tests baremetal. > Our build system creates 3 packages (kernel, kernel-modules, and > kernel-modules-internal), this allows us to ship the kernel and its > modules, while also isolating packages that we dont want to ship > outside of QE and developers. We then have our own infrastructure in > place to run and collect the output of these tests in our pipelined > environments. We dont utilize UML because we dont support that feature > in RHEL. > > Fedora uses this same methodology for running KUNIT, so we are > frequently running kunit on an 'upstream' variant. > > I'm not sure how many organizations are supporting continuous KUNIT > testing, or how they are achieving it, but dropping module support > would prevent us from doing the CI testing we have in place. > > Cheers! > -- Nico Fair enough -- we definitely won't get rid of it unless there's a replacement which works as well if not better. The reason it's tempting to get rid of KUNIT=m is simply that there's a chunk of KUnit code which needs to be built-in, even if the rest of it is in a module. So a kernel with KUNIT=m still has a fair bit of the overhead of KUNIT=y, and this is likely to get more significant as more such features land (e.g., static stubbing: https://lore.kernel.org/lkml/20220318021314.3225240-2-davidgow@google.com/ ). Traditionally, our expectation has been that a separate, KUnit-enabled kernel config / build makes sense, as that allows the release/production build to run without any testing-related overheads at all. That being said, I know Android are looking to enable KUnit in all GKI builds, and to implement a separate kunit.enable option to effectively "disable" it at runtime. This doesn't remove all of the overhead, but does allow KUnit to always be present without the risk of compromising the integrity of the running kernel by running tests in production. Regardless of whether any of those seem interesting to you, we won't be getting rid of KUNIT=m in the short-term (and definitely will be supporting individual test modules, even if we later want to have the core executor built-in). One other note is that KUNIT=m is actually broken right at the moment: the fix is here: https://patchwork.kernel.org/project/linux-kselftest/patch/20220713005221.1926290-1-davidgow@google.com/ Cheers, -- David
On Thu, Aug 11, 2022 at 7:41 AM Nico Pache <npache@redhat.com> wrote: > > Both the USB4 and Nitro Enclaves KUNIT tests are now able to be compiled > if KUNIT is compiled as a module. This leads to issues if KUNIT is being > packaged separately from the core kernel and when KUNIT is run baremetal > without the required driver compiled into the kernel. > > Fixes: 635dcd16844b ("thunderbolt: test: Use kunit_test_suite() macro") > Fixes: fe5be808fa6c ("nitro_enclaves: test: Use kunit_test_suite() macro") > Signed-off-by: Nico Pache <npache@redhat.com> > --- This is okay by me, though it's worth noting that this will stop these tests from building when CONFIG_KUNIT=m, so that the modules being tested will still load when CONFIG_KUNIT=m was enabled, but the kunit.ko file is missing. So if you're relying on being able to run these tests with CONFIG_KUNIT=m, you'll want to NACK this one. There's one comment below, but otherwise (assuming the USB4 and nitro_enclaves folks are okay with this tradeoff): Reviewed-by: David Gow <davidgow@google.com> Cheers, -- David > drivers/thunderbolt/Kconfig | 3 +-- > drivers/virt/nitro_enclaves/Kconfig | 2 +- > 2 files changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/thunderbolt/Kconfig b/drivers/thunderbolt/Kconfig > index e76a6c173637..f12d0a3ee3e2 100644 > --- a/drivers/thunderbolt/Kconfig > +++ b/drivers/thunderbolt/Kconfig > @@ -29,8 +29,7 @@ config USB4_DEBUGFS_WRITE > > config USB4_KUNIT_TEST > bool "KUnit tests" if !KUNIT_ALL_TESTS > - depends on (USB4=m || KUNIT=y) > - depends on KUNIT > + depends on USB4 && KUNIT=y "USB4 &&" shouldn't be necessary here: this opption is already under USB4, IIRC... > default KUNIT_ALL_TESTS > > config USB4_DMA_TEST > diff --git a/drivers/virt/nitro_enclaves/Kconfig b/drivers/virt/nitro_enclaves/Kconfig > index ce91add81401..dc4d25c26256 100644 > --- a/drivers/virt/nitro_enclaves/Kconfig > +++ b/drivers/virt/nitro_enclaves/Kconfig > @@ -17,7 +17,7 @@ config NITRO_ENCLAVES > > config NITRO_ENCLAVES_MISC_DEV_TEST > bool "Tests for the misc device functionality of the Nitro Enclaves" if !KUNIT_ALL_TESTS > - depends on NITRO_ENCLAVES && KUNIT > + depends on NITRO_ENCLAVES && KUNIT=y > default KUNIT_ALL_TESTS > help > Enable KUnit tests for the misc device functionality of the Nitro > -- > 2.36.1 >
On Thu, Aug 11, 2022 at 11:43 PM David Gow <davidgow@google.com> wrote: > > (+joefradley@google.com to comment on what Android is doing here) > > On Thu, Aug 11, 2022 at 8:44 PM Nico Pache <npache@redhat.com> wrote: > > > > On Wed, Aug 10, 2022 at 8:20 PM David Gow <davidgow@google.com> wrote: > > > > > > On Thu, Aug 11, 2022 at 7:41 AM Nico Pache <npache@redhat.com> wrote: > > > > > > > > Both the USB4 and Nitro Enclaves KUNIT tests are now able to be compiled > > > > if KUNIT is compiled as a module. This leads to issues if KUNIT is being > > > > packaged separately from the core kernel and when KUNIT is run baremetal > > > > without the required driver compiled into the kernel. > > > > > > > > Fixes: 635dcd16844b ("thunderbolt: test: Use kunit_test_suite() macro") > > > > Fixes: fe5be808fa6c ("nitro_enclaves: test: Use kunit_test_suite() macro") > > > > Signed-off-by: Nico Pache <npache@redhat.com> > > > > --- > > > > > > Hmm... I'm not quite sure I understand the case that's broken here. Is it: > > > - KUnit is built as a module (CONFIG_KUNIT=m) > > > - USB4/nitro_enclaves are also built as modules, with the test enabled. > > > - The kunit module is not available at runtime, so neither driver > > > module can load (due to missing kunit dependencies) > > Exactly, except the issue is also when the USB/NE=y not just when they > > are modules. This is currently creating an issue with our build system > > during the depmod stage and has been preventing us from generating > > Fedora builds. > . > Yeah: there's a nasty tradeoff here in that having these depend on > KUNIT=y does (obviously) mean that it's not possible to run these > tests with KUNIT=m. I'd agree that being able to ruin some tests is > better than none, but there are quite a lot of tests which are doing > the same sort of tricks as USB4/nitro_enclaves to embed tests in the > same module as the code being tested. In particular, I think apparmor > is doing something similar, and the incoming AMDGPU tests also build > all of the tests into amdgpu.ko. If we require KUNIT=y for these, > we're leaving a lot of tests on the table for KUNIT=m cases, which > would otherwise work. > > The ideal solution would be to split the tests for these systems out > into their own separate modules, but that's often quite tricky due to > the sheer number of otherwise internal symbols which need exporting. > > > > > > > If so, that's not a case (i.e., the kunit.ko module being unavailable > > > if it was built) we've tried to support thus far. I guess a de-facto > > > rule for supporting it would be to depend on KUNIT=y for any KUnit > > > tests which are built into the same module as the driver they're > > > testing. > > Yeah, although it's not been a case you've been trying to support, it > > has been working so far :) This has been the case (built-in tests > > utilizing 'depends on KUNIT=y') since we began supporting KUNIT in our > > testing infrastructure and it would be nice to keep that as a de-facto > > rule :) > > Okay: let's try to stick with that for now, then (unless there are any > objections from the people working on those particular tests), and > look to either reinstate it if we find a better way of dealing with > the missing/disabled kunit.ko case, or the tests can be split into a > separate module. Personally, I don't expect we'll get either of those > working in the short-term, but it's definitely a problem we'll have to > confront more eventually. > > In the meantime, I think the KUnit position on this will be to note > this as a consequence of building KUnit tests into bigger modules, and > leave the final decision up to the maintainers of those > subsystems/tests. This may result in there being some tests you have > to explicitly disable (rather than being able to use KUNIT_ALL_TESTS) > if an important module decides that they really want their tests to > run when KUNIT=m (which may not happen, we'll see...) > > > > > > > Alternatively, maybe we could do some horrible hacks to compile stub > > > versions of various KUnit assertion symbols in unconditionally, which > > > forward to the real ones if KUnit is available. > > > > > > (Personally, I'd love it if we could get rid of CONFIG_KUNIT=m > > > altogether, and it's actually broken right at the moment[1]. There are > > > still some cases (unloading / reloading KUnit with different filter > > > options) which require it, though.) > > Personally I'd hate to see KUNIT=m go as that is how we have been able > > to support running Kunit tests so far. > > > > A little background on how we utilize Kunit. We build with KUNIT=m and > > KUNIT_ALL_TESTS=m and run the tests baremetal. > > Our build system creates 3 packages (kernel, kernel-modules, and > > kernel-modules-internal), this allows us to ship the kernel and its > > modules, while also isolating packages that we dont want to ship > > outside of QE and developers. We then have our own infrastructure in > > place to run and collect the output of these tests in our pipelined > > environments. We dont utilize UML because we dont support that feature > > in RHEL. > > > > Fedora uses this same methodology for running KUNIT, so we are > > frequently running kunit on an 'upstream' variant. > > > > I'm not sure how many organizations are supporting continuous KUNIT > > testing, or how they are achieving it, but dropping module support > > would prevent us from doing the CI testing we have in place. > > > > Cheers! > > -- Nico > > Fair enough -- we definitely won't get rid of it unless there's a > replacement which works as well if not better. > > The reason it's tempting to get rid of KUNIT=m is simply that there's > a chunk of KUnit code which needs to be built-in, even if the rest of > it is in a module. So a kernel with KUNIT=m still has a fair bit of > the overhead of KUNIT=y, and this is likely to get more significant as > more such features land (e.g., static stubbing: > https://lore.kernel.org/lkml/20220318021314.3225240-2-davidgow@google.com/ > ). > > Traditionally, our expectation has been that a separate, KUnit-enabled > kernel config / build makes sense, as that allows the > release/production build to run without any testing-related overheads > at all. That being said, I know Android are looking to enable KUnit in > all GKI builds, and to implement a separate kunit.enable option to > effectively "disable" it at runtime. This doesn't remove all of the > overhead, but does allow KUnit to always be present without the risk > of compromising the integrity of the running kernel by running tests > in production. Like David mentioned, internally for GKI we have KUNIT=y with running built-in tests permanently disabled and only allowing module test execution if a kernel command line option (kunit.enable) is set. I hope to have an upstream patch of this for review soon. If you're willing to have the extra KUnit overhead in your production build, this could be an option for you as well. > > Regardless of whether any of those seem interesting to you, we won't > be getting rid of KUNIT=m in the short-term (and definitely will be > supporting individual test modules, even if we later want to have the > core executor built-in). > > One other note is that KUNIT=m is actually broken right at the moment: > the fix is here: > https://patchwork.kernel.org/project/linux-kselftest/patch/20220713005221.1926290-1-davidgow@google.com/ > > Cheers, > -- David
On Fri, Aug 12, 2022 at 2:43 AM David Gow <davidgow@google.com> wrote: > > (+joefradley@google.com to comment on what Android is doing here) > > On Thu, Aug 11, 2022 at 8:44 PM Nico Pache <npache@redhat.com> wrote: > > > > On Wed, Aug 10, 2022 at 8:20 PM David Gow <davidgow@google.com> wrote: > > > > > > On Thu, Aug 11, 2022 at 7:41 AM Nico Pache <npache@redhat.com> wrote: > > > > > > > > Both the USB4 and Nitro Enclaves KUNIT tests are now able to be compiled > > > > if KUNIT is compiled as a module. This leads to issues if KUNIT is being > > > > packaged separately from the core kernel and when KUNIT is run baremetal > > > > without the required driver compiled into the kernel. > > > > > > > > Fixes: 635dcd16844b ("thunderbolt: test: Use kunit_test_suite() macro") > > > > Fixes: fe5be808fa6c ("nitro_enclaves: test: Use kunit_test_suite() macro") > > > > Signed-off-by: Nico Pache <npache@redhat.com> > > > > --- > > > > > > Hmm... I'm not quite sure I understand the case that's broken here. Is it: > > > - KUnit is built as a module (CONFIG_KUNIT=m) > > > - USB4/nitro_enclaves are also built as modules, with the test enabled. > > > - The kunit module is not available at runtime, so neither driver > > > module can load (due to missing kunit dependencies) > > Exactly, except the issue is also when the USB/NE=y not just when they > > are modules. This is currently creating an issue with our build system > > during the depmod stage and has been preventing us from generating > > Fedora builds. > . > Yeah: there's a nasty tradeoff here in that having these depend on > KUNIT=y does (obviously) mean that it's not possible to run these > tests with KUNIT=m. I'd agree that being able to ruin some tests is > better than none, but there are quite a lot of tests which are doing > the same sort of tricks as USB4/nitro_enclaves to embed tests in the > same module as the code being tested. In particular, I think apparmor > is doing something similar, and the incoming AMDGPU tests also build > all of the tests into amdgpu.ko. If we require KUNIT=y for these, > we're leaving a lot of tests on the table for KUNIT=m cases, which > would otherwise work. > > The ideal solution would be to split the tests for these systems out > into their own separate modules, but that's often quite tricky due to > the sheer number of otherwise internal symbols which need exporting. I have already started trying to separate out all the built-in tests. There are a few which may have to stay as built-in if I can't find a viable solution, but expect a patch-set doing just this soon :) > > > > > > If so, that's not a case (i.e., the kunit.ko module being unavailable > > > if it was built) we've tried to support thus far. I guess a de-facto > > > rule for supporting it would be to depend on KUNIT=y for any KUnit > > > tests which are built into the same module as the driver they're > > > testing. > > Yeah, although it's not been a case you've been trying to support, it > > has been working so far :) This has been the case (built-in tests > > utilizing 'depends on KUNIT=y') since we began supporting KUNIT in our > > testing infrastructure and it would be nice to keep that as a de-facto > > rule :) > > Okay: let's try to stick with that for now, then (unless there are any > objections from the people working on those particular tests), and > look to either reinstate it if we find a better way of dealing with > the missing/disabled kunit.ko case, or the tests can be split into a > separate module. Personally, I don't expect we'll get either of those > working in the short-term, but it's definitely a problem we'll have to > confront more eventually. > > In the meantime, I think the KUnit position on this will be to note > this as a consequence of building KUnit tests into bigger modules, and > leave the final decision up to the maintainers of those > subsystems/tests. This may result in there being some tests you have > to explicitly disable (rather than being able to use KUNIT_ALL_TESTS) > if an important module decides that they really want their tests to > run when KUNIT=m (which may not happen, we'll see...) Yep, explicitly disabling them is also an option for us, but I submitted this patchset because I noticed a change in the pattern for built-in tests (depends on KUNIT=y). So if people object to some tests not having kunit module support, we do have the ability to work around it. Thanks for your review! Cheers, -- Nico > > > > > > > Alternatively, maybe we could do some horrible hacks to compile stub > > > versions of various KUnit assertion symbols in unconditionally, which > > > forward to the real ones if KUnit is available. > > > > > > (Personally, I'd love it if we could get rid of CONFIG_KUNIT=m > > > altogether, and it's actually broken right at the moment[1]. There are > > > still some cases (unloading / reloading KUnit with different filter > > > options) which require it, though.) > > Personally I'd hate to see KUNIT=m go as that is how we have been able > > to support running Kunit tests so far. > > > > A little background on how we utilize Kunit. We build with KUNIT=m and > > KUNIT_ALL_TESTS=m and run the tests baremetal. > > Our build system creates 3 packages (kernel, kernel-modules, and > > kernel-modules-internal), this allows us to ship the kernel and its > > modules, while also isolating packages that we dont want to ship > > outside of QE and developers. We then have our own infrastructure in > > place to run and collect the output of these tests in our pipelined > > environments. We dont utilize UML because we dont support that feature > > in RHEL. > > > > Fedora uses this same methodology for running KUNIT, so we are > > frequently running kunit on an 'upstream' variant. > > > > I'm not sure how many organizations are supporting continuous KUNIT > > testing, or how they are achieving it, but dropping module support > > would prevent us from doing the CI testing we have in place. > > > > Cheers! > > -- Nico > > Fair enough -- we definitely won't get rid of it unless there's a > replacement which works as well if not better. > > The reason it's tempting to get rid of KUNIT=m is simply that there's > a chunk of KUnit code which needs to be built-in, even if the rest of > it is in a module. So a kernel with KUNIT=m still has a fair bit of > the overhead of KUNIT=y, and this is likely to get more significant as > more such features land (e.g., static stubbing: > https://lore.kernel.org/lkml/20220318021314.3225240-2-davidgow@google.com/ > ). > > Traditionally, our expectation has been that a separate, KUnit-enabled > kernel config / build makes sense, as that allows the > release/production build to run without any testing-related overheads > at all. That being said, I know Android are looking to enable KUnit in > all GKI builds, and to implement a separate kunit.enable option to > effectively "disable" it at runtime. This doesn't remove all of the > overhead, but does allow KUnit to always be present without the risk > of compromising the integrity of the running kernel by running tests > in production. > > Regardless of whether any of those seem interesting to you, we won't > be getting rid of KUNIT=m in the short-term (and definitely will be > supporting individual test modules, even if we later want to have the > core executor built-in). > > One other note is that KUNIT=m is actually broken right at the moment: > the fix is here: > https://patchwork.kernel.org/project/linux-kselftest/patch/20220713005221.1926290-1-davidgow@google.com/ > > Cheers, > -- David >
On Fri, Aug 12, 2022 at 12:15 PM Joe Fradley <joefradley@google.com> wrote: > > On Thu, Aug 11, 2022 at 11:43 PM David Gow <davidgow@google.com> wrote: > > > > (+joefradley@google.com to comment on what Android is doing here) > > > > On Thu, Aug 11, 2022 at 8:44 PM Nico Pache <npache@redhat.com> wrote: > > > > > > On Wed, Aug 10, 2022 at 8:20 PM David Gow <davidgow@google.com> wrote: > > > > > > > > On Thu, Aug 11, 2022 at 7:41 AM Nico Pache <npache@redhat.com> wrote: > > > > > > > > > > Both the USB4 and Nitro Enclaves KUNIT tests are now able to be compiled > > > > > if KUNIT is compiled as a module. This leads to issues if KUNIT is being > > > > > packaged separately from the core kernel and when KUNIT is run baremetal > > > > > without the required driver compiled into the kernel. > > > > > > > > > > Fixes: 635dcd16844b ("thunderbolt: test: Use kunit_test_suite() macro") > > > > > Fixes: fe5be808fa6c ("nitro_enclaves: test: Use kunit_test_suite() macro") > > > > > Signed-off-by: Nico Pache <npache@redhat.com> > > > > > --- > > > > > > > > Hmm... I'm not quite sure I understand the case that's broken here. Is it: > > > > - KUnit is built as a module (CONFIG_KUNIT=m) > > > > - USB4/nitro_enclaves are also built as modules, with the test enabled. > > > > - The kunit module is not available at runtime, so neither driver > > > > module can load (due to missing kunit dependencies) > > > Exactly, except the issue is also when the USB/NE=y not just when they > > > are modules. This is currently creating an issue with our build system > > > during the depmod stage and has been preventing us from generating > > > Fedora builds. > > . > > Yeah: there's a nasty tradeoff here in that having these depend on > > KUNIT=y does (obviously) mean that it's not possible to run these > > tests with KUNIT=m. I'd agree that being able to ruin some tests is > > better than none, but there are quite a lot of tests which are doing > > the same sort of tricks as USB4/nitro_enclaves to embed tests in the > > same module as the code being tested. In particular, I think apparmor > > is doing something similar, and the incoming AMDGPU tests also build > > all of the tests into amdgpu.ko. If we require KUNIT=y for these, > > we're leaving a lot of tests on the table for KUNIT=m cases, which > > would otherwise work. > > > > The ideal solution would be to split the tests for these systems out > > into their own separate modules, but that's often quite tricky due to > > the sheer number of otherwise internal symbols which need exporting. > > > > > > > > > > If so, that's not a case (i.e., the kunit.ko module being unavailable > > > > if it was built) we've tried to support thus far. I guess a de-facto > > > > rule for supporting it would be to depend on KUNIT=y for any KUnit > > > > tests which are built into the same module as the driver they're > > > > testing. > > > Yeah, although it's not been a case you've been trying to support, it > > > has been working so far :) This has been the case (built-in tests > > > utilizing 'depends on KUNIT=y') since we began supporting KUNIT in our > > > testing infrastructure and it would be nice to keep that as a de-facto > > > rule :) > > > > Okay: let's try to stick with that for now, then (unless there are any > > objections from the people working on those particular tests), and > > look to either reinstate it if we find a better way of dealing with > > the missing/disabled kunit.ko case, or the tests can be split into a > > separate module. Personally, I don't expect we'll get either of those > > working in the short-term, but it's definitely a problem we'll have to > > confront more eventually. > > > > In the meantime, I think the KUnit position on this will be to note > > this as a consequence of building KUnit tests into bigger modules, and > > leave the final decision up to the maintainers of those > > subsystems/tests. This may result in there being some tests you have > > to explicitly disable (rather than being able to use KUNIT_ALL_TESTS) > > if an important module decides that they really want their tests to > > run when KUNIT=m (which may not happen, we'll see...) > > > > > > > > > > Alternatively, maybe we could do some horrible hacks to compile stub > > > > versions of various KUnit assertion symbols in unconditionally, which > > > > forward to the real ones if KUnit is available. > > > > > > > > (Personally, I'd love it if we could get rid of CONFIG_KUNIT=m > > > > altogether, and it's actually broken right at the moment[1]. There are > > > > still some cases (unloading / reloading KUnit with different filter > > > > options) which require it, though.) > > > Personally I'd hate to see KUNIT=m go as that is how we have been able > > > to support running Kunit tests so far. > > > > > > A little background on how we utilize Kunit. We build with KUNIT=m and > > > KUNIT_ALL_TESTS=m and run the tests baremetal. > > > Our build system creates 3 packages (kernel, kernel-modules, and > > > kernel-modules-internal), this allows us to ship the kernel and its > > > modules, while also isolating packages that we dont want to ship > > > outside of QE and developers. We then have our own infrastructure in > > > place to run and collect the output of these tests in our pipelined > > > environments. We dont utilize UML because we dont support that feature > > > in RHEL. > > > > > > Fedora uses this same methodology for running KUNIT, so we are > > > frequently running kunit on an 'upstream' variant. > > > > > > I'm not sure how many organizations are supporting continuous KUNIT > > > testing, or how they are achieving it, but dropping module support > > > would prevent us from doing the CI testing we have in place. > > > > > > Cheers! > > > -- Nico > > > > Fair enough -- we definitely won't get rid of it unless there's a > > replacement which works as well if not better. > > > > The reason it's tempting to get rid of KUNIT=m is simply that there's > > a chunk of KUnit code which needs to be built-in, even if the rest of > > it is in a module. So a kernel with KUNIT=m still has a fair bit of > > the overhead of KUNIT=y, and this is likely to get more significant as > > more such features land (e.g., static stubbing: > > https://lore.kernel.org/lkml/20220318021314.3225240-2-davidgow@google.com/ > > ). > > > > Traditionally, our expectation has been that a separate, KUnit-enabled > > kernel config / build makes sense, as that allows the > > release/production build to run without any testing-related overheads > > at all. That being said, I know Android are looking to enable KUnit in > > all GKI builds, and to implement a separate kunit.enable option to > > effectively "disable" it at runtime. This doesn't remove all of the > > overhead, but does allow KUnit to always be present without the risk > > of compromising the integrity of the running kernel by running tests > > in production. > > Like David mentioned, internally for GKI we have KUNIT=y with running > built-in tests permanently disabled and only allowing module test > execution if a kernel command line option (kunit.enable) is set. I > hope to have an upstream patch of this for review soon. If you're > willing to have the extra KUnit overhead in your production build, > this could be an option for you as well. Sweet :) I look forward to seeing that! That may be a viable option for our approach too. Cheers, -- Nico > > > > > Regardless of whether any of those seem interesting to you, we won't > > be getting rid of KUNIT=m in the short-term (and definitely will be > > supporting individual test modules, even if we later want to have the > > core executor built-in). > > > > One other note is that KUNIT=m is actually broken right at the moment: > > the fix is here: > > https://patchwork.kernel.org/project/linux-kselftest/patch/20220713005221.1926290-1-davidgow@google.com/ > > > > Cheers, > > -- David >
On 11.08.2022 02:40, Nico Pache wrote: > > Both the USB4 and Nitro Enclaves KUNIT tests are now able to be compiled > if KUNIT is compiled as a module. This leads to issues if KUNIT is being > packaged separately from the core kernel and when KUNIT is run baremetal > without the required driver compiled into the kernel. > > Fixes: 635dcd16844b ("thunderbolt: test: Use kunit_test_suite() macro") > Fixes: fe5be808fa6c ("nitro_enclaves: test: Use kunit_test_suite() macro") > Signed-off-by: Nico Pache <npache@redhat.com> > --- > drivers/thunderbolt/Kconfig | 3 +-- > drivers/virt/nitro_enclaves/Kconfig | 2 +- > 2 files changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/thunderbolt/Kconfig b/drivers/thunderbolt/Kconfig > index e76a6c173637..f12d0a3ee3e2 100644 > --- a/drivers/thunderbolt/Kconfig > +++ b/drivers/thunderbolt/Kconfig > @@ -29,8 +29,7 @@ config USB4_DEBUGFS_WRITE > > config USB4_KUNIT_TEST > bool "KUnit tests" if !KUNIT_ALL_TESTS > - depends on (USB4=m || KUNIT=y) > - depends on KUNIT > + depends on USB4 && KUNIT=y > default KUNIT_ALL_TESTS > > config USB4_DMA_TEST > diff --git a/drivers/virt/nitro_enclaves/Kconfig b/drivers/virt/nitro_enclaves/Kconfig > index ce91add81401..dc4d25c26256 100644 > --- a/drivers/virt/nitro_enclaves/Kconfig > +++ b/drivers/virt/nitro_enclaves/Kconfig > @@ -17,7 +17,7 @@ config NITRO_ENCLAVES > > config NITRO_ENCLAVES_MISC_DEV_TEST > bool "Tests for the misc device functionality of the Nitro Enclaves" if !KUNIT_ALL_TESTS > - depends on NITRO_ENCLAVES && KUNIT > + depends on NITRO_ENCLAVES && KUNIT=y > default KUNIT_ALL_TESTS > help > Enable KUnit tests for the misc device functionality of the Nitro For the Nitro Enclaves part: Reviewed-by: Andra Paraschiv <andraprs@amazon.com> Thank you. Andra > -- > 2.36.1 > Amazon Development Center (Romania) S.R.L. registered office: 27A Sf. Lazar Street, UBC5, floor 2, Iasi, Iasi County, 700045, Romania. Registered in Romania. Registration number J22/2621/2005.
On Wed, Aug 10, 2022 at 4:41 PM Nico Pache <npache@redhat.com> wrote: > > Both the USB4 and Nitro Enclaves KUNIT tests are now able to be compiled > if KUNIT is compiled as a module. This leads to issues if KUNIT is being > packaged separately from the core kernel and when KUNIT is run baremetal > without the required driver compiled into the kernel. > > Fixes: 635dcd16844b ("thunderbolt: test: Use kunit_test_suite() macro") > Fixes: fe5be808fa6c ("nitro_enclaves: test: Use kunit_test_suite() macro") > Signed-off-by: Nico Pache <npache@redhat.com> Acked-by: Brendan Higgins <brendanhiggins@google.com>
diff --git a/drivers/thunderbolt/Kconfig b/drivers/thunderbolt/Kconfig index e76a6c173637..f12d0a3ee3e2 100644 --- a/drivers/thunderbolt/Kconfig +++ b/drivers/thunderbolt/Kconfig @@ -29,8 +29,7 @@ config USB4_DEBUGFS_WRITE config USB4_KUNIT_TEST bool "KUnit tests" if !KUNIT_ALL_TESTS - depends on (USB4=m || KUNIT=y) - depends on KUNIT + depends on USB4 && KUNIT=y default KUNIT_ALL_TESTS config USB4_DMA_TEST diff --git a/drivers/virt/nitro_enclaves/Kconfig b/drivers/virt/nitro_enclaves/Kconfig index ce91add81401..dc4d25c26256 100644 --- a/drivers/virt/nitro_enclaves/Kconfig +++ b/drivers/virt/nitro_enclaves/Kconfig @@ -17,7 +17,7 @@ config NITRO_ENCLAVES config NITRO_ENCLAVES_MISC_DEV_TEST bool "Tests for the misc device functionality of the Nitro Enclaves" if !KUNIT_ALL_TESTS - depends on NITRO_ENCLAVES && KUNIT + depends on NITRO_ENCLAVES && KUNIT=y default KUNIT_ALL_TESTS help Enable KUnit tests for the misc device functionality of the Nitro
Both the USB4 and Nitro Enclaves KUNIT tests are now able to be compiled if KUNIT is compiled as a module. This leads to issues if KUNIT is being packaged separately from the core kernel and when KUNIT is run baremetal without the required driver compiled into the kernel. Fixes: 635dcd16844b ("thunderbolt: test: Use kunit_test_suite() macro") Fixes: fe5be808fa6c ("nitro_enclaves: test: Use kunit_test_suite() macro") Signed-off-by: Nico Pache <npache@redhat.com> --- drivers/thunderbolt/Kconfig | 3 +-- drivers/virt/nitro_enclaves/Kconfig | 2 +- 2 files changed, 2 insertions(+), 3 deletions(-)