From a1af6a2bfa0cb46d70b7df5352993e750da6c79b Mon Sep 17 00:00:00 2001 From: Marco Pagani Date: Wed, 10 Jan 2024 16:59:47 +0100 Subject: kunit: run test suites only after module initialization completes Commit 2810c1e99867 ("kunit: Fix wild-memory-access bug in kunit_free_suite_set()") fixed a wild-memory-access bug that could have happened during the loading phase of test suites built and executed as loadable modules. However, it also introduced a problematic side effect that causes test suites modules to crash when they attempt to register fake devices. When a module is loaded, it traverses the MODULE_STATE_UNFORMED and MODULE_STATE_COMING states before reaching the normal operating state MODULE_STATE_LIVE. Finally, when the module is removed, it moves to MODULE_STATE_GOING before being released. However, if the loading function load_module() fails between complete_formation() and do_init_module(), the module goes directly from MODULE_STATE_COMING to MODULE_STATE_GOING without passing through MODULE_STATE_LIVE. This behavior was causing kunit_module_exit() to be called without having first executed kunit_module_init(). Since kunit_module_exit() is responsible for freeing the memory allocated by kunit_module_init() through kunit_filter_suites(), this behavior was resulting in a wild-memory-access bug. Commit 2810c1e99867 ("kunit: Fix wild-memory-access bug in kunit_free_suite_set()") fixed this issue by running the tests when the module is still in MODULE_STATE_COMING. However, modules in that state are not fully initialized, lacking sysfs kobjects. Therefore, if a test module attempts to register a fake device, it will inevitably crash. This patch proposes a different approach to fix the original wild-memory-access bug while restoring the normal module execution flow by making kunit_module_exit() able to detect if kunit_module_init() has previously initialized the tests suite set. In this way, test modules can once again register fake devices without crashing. This behavior is achieved by checking whether mod->kunit_suites is a virtual or direct mapping address. If it is a virtual address, then kunit_module_init() has allocated the suite_set in kunit_filter_suites() using kmalloc_array(). On the contrary, if mod->kunit_suites is still pointing to the original address that was set when looking up the .kunit_test_suites section of the module, then the loading phase has failed and there's no memory to be freed. v4: - rebased on 6.8 - noted that kunit_filter_suites() must return a virtual address v3: - add a comment to clarify why the start address is checked v2: - add include Fixes: 2810c1e99867 ("kunit: Fix wild-memory-access bug in kunit_free_suite_set()") Reviewed-by: David Gow Tested-by: Rae Moar Tested-by: Richard Fitzgerald Reviewed-by: Javier Martinez Canillas Signed-off-by: Marco Pagani Signed-off-by: Shuah Khan --- lib/kunit/test.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'lib/kunit/test.c') diff --git a/lib/kunit/test.c b/lib/kunit/test.c index f95d2093a0aa..31a5a992e646 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -17,6 +17,7 @@ #include #include #include +#include #include "debugfs.h" #include "device-impl.h" @@ -801,12 +802,19 @@ static void kunit_module_exit(struct module *mod) }; const char *action = kunit_action(); + /* + * Check if the start address is a valid virtual address to detect + * if the module load sequence has failed and the suite set has not + * been initialized and filtered. + */ + if (!suite_set.start || !virt_addr_valid(suite_set.start)) + return; + if (!action) __kunit_test_suites_exit(mod->kunit_suites, mod->num_kunit_suites); - if (suite_set.start) - kunit_free_suite_set(suite_set); + kunit_free_suite_set(suite_set); } static int kunit_module_notify(struct notifier_block *nb, unsigned long val, @@ -816,12 +824,12 @@ static int kunit_module_notify(struct notifier_block *nb, unsigned long val, switch (val) { case MODULE_STATE_LIVE: + kunit_module_init(mod); break; case MODULE_STATE_GOING: kunit_module_exit(mod); break; case MODULE_STATE_COMING: - kunit_module_init(mod); break; case MODULE_STATE_UNFORMED: break; -- cgit v1.2.3 From 829388b725f8d266ccec32a2f446717d8693eaba Mon Sep 17 00:00:00 2001 From: David Gow Date: Thu, 1 Feb 2024 14:04:36 +0800 Subject: kunit: device: Unregister the kunit_bus on shutdown If KUnit is built as a module, and it's unloaded, the kunit_bus is not unregistered. This causes an error if it's then re-loaded later, as we try to re-register the bus. Unregister the bus and root_device on shutdown, if it looks valid. In addition, be more specific about the value of kunit_bus_device. It is: - a valid struct device* if the kunit_bus initialised correctly. - an ERR_PTR if it failed to initialise. - NULL before initialisation and after shutdown. Fixes: d03c720e03bd ("kunit: Add APIs for managing devices") Signed-off-by: David Gow Reviewed-by: Rae Moar Signed-off-by: Shuah Khan --- lib/kunit/device-impl.h | 2 ++ lib/kunit/device.c | 14 ++++++++++++++ lib/kunit/test.c | 3 +++ 3 files changed, 19 insertions(+) (limited to 'lib/kunit/test.c') diff --git a/lib/kunit/device-impl.h b/lib/kunit/device-impl.h index 54bd55836405..5fcd48ff0f36 100644 --- a/lib/kunit/device-impl.h +++ b/lib/kunit/device-impl.h @@ -13,5 +13,7 @@ // For internal use only -- registers the kunit_bus. int kunit_bus_init(void); +// For internal use only -- unregisters the kunit_bus. +void kunit_bus_shutdown(void); #endif //_KUNIT_DEVICE_IMPL_H diff --git a/lib/kunit/device.c b/lib/kunit/device.c index 074c6dd2e36a..644a38a1f5b1 100644 --- a/lib/kunit/device.c +++ b/lib/kunit/device.c @@ -54,6 +54,20 @@ int kunit_bus_init(void) return error; } +/* Unregister the 'kunit_bus' in case the KUnit module is unloaded. */ +void kunit_bus_shutdown(void) +{ + /* Make sure the bus exists before we unregister it. */ + if (IS_ERR_OR_NULL(kunit_bus_device)) + return; + + bus_unregister(&kunit_bus_type); + + root_device_unregister(kunit_bus_device); + + kunit_bus_device = NULL; +} + /* Release a 'fake' KUnit device. */ static void kunit_device_release(struct device *d) { diff --git a/lib/kunit/test.c b/lib/kunit/test.c index 31a5a992e646..1d1475578515 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -928,6 +928,9 @@ static void __exit kunit_exit(void) #ifdef CONFIG_MODULES unregister_module_notifier(&kunit_mod_nb); #endif + + kunit_bus_shutdown(); + kunit_debugfs_cleanup(); } module_exit(kunit_exit); -- cgit v1.2.3