On Sat, Feb 29, 2020 at 2:09 AM Patricia Alfonso trishalfonso@google.com wrote:
kasan-dev@googlegroups.com wrote:
Integrate KASAN into KUnit testing framework.
- Fail tests when KASAN reports an error that is not expected
- Use KUNIT_EXPECT_KASAN_FAIL to expect a KASAN error in KASAN tests
- KUnit struct added to current task to keep track of the current test
from KASAN code
- Booleans representing if a KASAN report is expected and if a KASAN
report is found added to kunit struct
- This prints "line# has passed" or "line# has failed"
Signed-off-by: Patricia Alfonso trishalfonso@google.com
If anyone has any suggestions on how best to print the failure messages, please share!
One issue I have found while testing this is the allocation fails in kmalloc_pagealloc_oob_right() sometimes, but not consistently. This does cause the test to fail on the KUnit side, as expected, but it seems to skip all the tests before this one because the output starts with this failure instead of with the first test, kmalloc_oob_right().
include/kunit/test.h | 24 ++++++++++++++++++++++++ include/linux/sched.h | 7 ++++++- lib/kunit/test.c | 7 ++++++- mm/kasan/report.c | 19 +++++++++++++++++++ tools/testing/kunit/kunit_kernel.py | 2 +- 5 files changed, 56 insertions(+), 3 deletions(-)
diff --git a/include/kunit/test.h b/include/kunit/test.h index 2dfb550c6723..2e388f8937f3 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -21,6 +21,8 @@ struct kunit_resource; typedef int (*kunit_resource_init_t)(struct kunit_resource *, void *); typedef void (*kunit_resource_free_t)(struct kunit_resource *);
+void kunit_set_failure(struct kunit *test);
/**
- struct kunit_resource - represents a *test managed resource*
- @allocation: for the user to store arbitrary data.
@@ -191,6 +193,9 @@ struct kunit { * protect it with some type of lock. */ struct list_head resources; /* Protected by lock. */
bool kasan_report_expected;bool kasan_report_found;};
void kunit_init_test(struct kunit *test, const char *name); @@ -941,6 +946,25 @@ do { \ ptr, \ NULL)
+/**
- KUNIT_EXPECT_KASAN_FAIL() - Causes a test failure when the expression does
- not cause a KASAN error.
Oh, I see, this is not a test, but rather an ASSERT-like macro. Then maybe we should use it for actual expressions that are supposed to trigger KASAN errors?
E.g. KUNIT_EXPECT_KASAN_FAIL(test, *(volatile int*)p);
This is one possible approach. I wasn't sure what would be the most useful. Would it be most useful to assert an error is reported on a function or assert an error is reported at a specific address?
I would say assert on a specific line of code/expression for locality reasons. This will also solve the problem for tests that trigger several reports, this way we can check that we get N reports.
- */
+#define KUNIT_EXPECT_KASAN_FAIL(test, condition) do { \
s/condition/expression/
test->kasan_report_expected = true; \Check that kasan_report_expected is unset. If these are nested things will break in confusing ways. Or otherwise we need to restore the previous value at the end.
Good point! I think I was just unsure of where I should set this value and what the default should be.
test->kasan_report_found = false; \condition; \if (test->kasan_report_found == test->kasan_report_expected) { \We know that kasan_report_expected is true here, so we could just said:
if (!test->kasan_report_found)
Good point! This is much more readable
pr_info("%d has passed", __LINE__); \} else { \kunit_set_failure(test); \pr_info("%d has failed", __LINE__); \This needs a more readable error.
Yes, this was just a stand-in. I was wondering if you might have a suggestion for the best way to print this failure message? Alan suggested reusing the KUNIT_EXPECT_EQ() macro so the error message would look something like: "Expected kasan_report_expected == kasan_report_found, but kasan_report_expected == true kasan_report_found == false"
What do you think of this?
I will be able to understand why the test has failed reading this error message. A more human-friendly message may be better, but if this makes for better consistency I am fine with this.
} \test->kasan_report_expected = false; \test->kasan_report_found = false; \+} while (0)
/**
- KUNIT_EXPECT_TRUE() - Causes a test failure when the expression is not true.
- @test: The test context object.
diff --git a/include/linux/sched.h b/include/linux/sched.h index 04278493bf15..db23d56061e7 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -32,6 +32,8 @@ #include <linux/posix-timers.h> #include <linux/rseq.h>
+#include <kunit/test.h>
/* task_struct member predeclarations (sorted alphabetically): */ struct audit_context; struct backing_dev_info; @@ -1178,7 +1180,10 @@ struct task_struct {
#ifdef CONFIG_KASAN unsigned int kasan_depth; -#endif +#ifdef CONFIG_KUNIT
struct kunit *kasan_kunit_test;I would assume we will use this for other things as well (failing tests on LOCKDEP errors, WARNINGs, etc). So I would call this just kunit_test and make non-dependent on KASAN right away.
Yeah, I think I just wanted to make it clear that this is only used for KASAN, but I believe that was before we talked about extending this.
if (current->kasan_kunit_test) {Strictly saying, this also needs to check in_task().
I was not aware of in_task()... can you explain its importance to me?
if (current->kasan_kunit_test->kasan_report_expected) {current->kasan_kunit_test->kasan_report_found = true;return;}kunit_set_failure(current->kasan_kunit_test);}This chunk is duplicated 2 times. I think it will be more reasonable for KASAN code to just notify KUNIT that the error has happened, and then KUNIT will figure out what it means and what to do.
Yeah, I think moving this to the KUnit files is best too. I would like to keep kunit_set_failure a static function as well.
-- Thank you for the comments!
Patricia Alfonso