diff options
author | Marco Pagani <marpagan@redhat.com> | 2024-01-10 18:59:47 +0300 |
---|---|---|
committer | Shuah Khan <skhan@linuxfoundation.org> | 2024-01-22 17:58:54 +0300 |
commit | a1af6a2bfa0cb46d70b7df5352993e750da6c79b (patch) | |
tree | 7e2fab88d41f7833cf81d29474b6a4f35c51808c | |
parent | 57e39086fb868a84f772cf097004f4715d8aaccb (diff) | |
download | linux-a1af6a2bfa0cb46d70b7df5352993e750da6c79b.tar.xz |
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 <linux/mm.h>
Fixes: 2810c1e99867 ("kunit: Fix wild-memory-access bug in kunit_free_suite_set()")
Reviewed-by: David Gow <davidgow@google.com>
Tested-by: Rae Moar <rmoar@google.com>
Tested-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Marco Pagani <marpagan@redhat.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
-rw-r--r-- | lib/kunit/executor.c | 4 | ||||
-rw-r--r-- | lib/kunit/test.c | 14 |
2 files changed, 15 insertions, 3 deletions
diff --git a/lib/kunit/executor.c b/lib/kunit/executor.c index 717b9599036b..689fff2b2b10 100644 --- a/lib/kunit/executor.c +++ b/lib/kunit/executor.c @@ -146,6 +146,10 @@ void kunit_free_suite_set(struct kunit_suite_set suite_set) kfree(suite_set.start); } +/* + * Filter and reallocate test suites. Must return the filtered test suites set + * allocated at a valid virtual address or NULL in case of error. + */ struct kunit_suite_set kunit_filter_suites(const struct kunit_suite_set *suite_set, const char *filter_glob, 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 <linux/panic.h> #include <linux/sched/debug.h> #include <linux/sched.h> +#include <linux/mm.h> #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; |