| Message ID | 20220702040959.3232874-4-davidgow@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v5,1/4] panic: Taint kernel if tests are run | expand |
On Sat, Jul 2, 2022 at 12:10 PM David Gow <davidgow@google.com> wrote: > > Make any kselftest test module (using the kselftest_module framework) > taint the kernel with TAINT_TEST on module load. > > Also mark the module as a test module using MODULE_INFO(test, "Y") so > that other tools can tell this is a test module. We can't rely solely > on this, though, as these test modules are also often built-in. > > Finally, update the kselftest documentation to mention that the kernel > should be tainted, and how to do so manually (as below). > > Note that several selftests use kernel modules which are not based on > the kselftest_module framework, and so will not automatically taint the > kernel. > > This can be done in two ways: > - Moving the module to the tools/testing directory. All modules under > this directory will taint the kernel. > - Adding the 'test' module property with: > MODULE_INFO(test, "Y") > > Similarly, selftests which do not load modules into the kernel generally > should not taint the kernel (or possibly should only do so on failure), > as it's assumed that testing from user-space should be safe. Regardless, > they can write to /proc/sys/kernel/tainted if required. > > Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> > Signed-off-by: David Gow <davidgow@google.com> > --- Whoops: forgot the changelogs. Only patches 2 and 4 had changes. For this patch: Changes since v4: https://lore.kernel.org/lkml/20220513083212.3537869-3-davidgow@google.com/ - Actually use the new TAINT_TEST name, instead of TAINT_KUNIT (Thanks, kernel-test-robot) - Document how to use this (or MODULE_INFO()) to taint the kernel. (Thanks, Luis) - Also add MODULE_INFO(test, "Y") to embed the fact that this is a test module into the .ko - Nothing depends on it now, but it should allow us to tell this is a test module without executing it in the future. No changes since v3: https://lore.kernel.org/lkml/20220513083212.3537869-3-davidgow@google.com/
On Sat, Jul 2, 2022 at 12:10 AM David Gow <davidgow@google.com> wrote: > > Make any kselftest test module (using the kselftest_module framework) > taint the kernel with TAINT_TEST on module load. > > Also mark the module as a test module using MODULE_INFO(test, "Y") so > that other tools can tell this is a test module. We can't rely solely > on this, though, as these test modules are also often built-in. > > Finally, update the kselftest documentation to mention that the kernel > should be tainted, and how to do so manually (as below). > > Note that several selftests use kernel modules which are not based on > the kselftest_module framework, and so will not automatically taint the > kernel. > > This can be done in two ways: > - Moving the module to the tools/testing directory. All modules under > this directory will taint the kernel. > - Adding the 'test' module property with: > MODULE_INFO(test, "Y") > > Similarly, selftests which do not load modules into the kernel generally > should not taint the kernel (or possibly should only do so on failure), > as it's assumed that testing from user-space should be safe. Regardless, > they can write to /proc/sys/kernel/tainted if required. > > Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> > Signed-off-by: David Gow <davidgow@google.com> Acked-by: Brendan Higgins <brendanhiggins@google.com>
diff --git a/Documentation/dev-tools/kselftest.rst b/Documentation/dev-tools/kselftest.rst index a833ecf12fbc..1096a9833550 100644 --- a/Documentation/dev-tools/kselftest.rst +++ b/Documentation/dev-tools/kselftest.rst @@ -250,6 +250,14 @@ assist writing kernel modules that are for use with kselftest: - ``tools/testing/selftests/kselftest_module.h`` - ``tools/testing/selftests/kselftest/module.sh`` +Note that test modules should taint the kernel with TAINT_TEST. This will +happen automatically for modules which are in the ``tools/testing/`` +directory, or for modules which use the ``kselftest_module.h`` header above. +Otherwise, you'll need to add ``MODULE_INFO(test, "Y")`` to your module +source. selftests which do not load modules typically should not taint the +kernel, but in cases where a non-test module is loaded, TEST_TAINT can be +applied from userspace by writing to ``/proc/sys/kernel/tainted``. + How to use ---------- @@ -308,6 +316,7 @@ A bare bones test module might look like this: KSTM_MODULE_LOADERS(test_foo); MODULE_AUTHOR("John Developer <jd@fooman.org>"); MODULE_LICENSE("GPL"); + MODULE_INFO(test, "Y"); Example test script ------------------- diff --git a/tools/testing/selftests/kselftest_module.h b/tools/testing/selftests/kselftest_module.h index e2ea41de3f35..63cd7487373f 100644 --- a/tools/testing/selftests/kselftest_module.h +++ b/tools/testing/selftests/kselftest_module.h @@ -3,6 +3,7 @@ #define __KSELFTEST_MODULE_H #include <linux/module.h> +#include <linux/panic.h> /* * Test framework for writing test modules to be loaded by kselftest. @@ -41,6 +42,7 @@ static inline int kstm_report(unsigned int total_tests, unsigned int failed_test static int __init __module##_init(void) \ { \ pr_info("loaded.\n"); \ + add_taint(TAINT_TEST, LOCKDEP_STILL_OK); \ selftest(); \ return kstm_report(total_tests, failed_tests, skipped_tests); \ } \ @@ -51,4 +53,6 @@ static void __exit __module##_exit(void) \ module_init(__module##_init); \ module_exit(__module##_exit) +MODULE_INFO(test, "Y"); + #endif /* __KSELFTEST_MODULE_H */