Hi Andrey,

quoted

quoted

Right now, KASAN tests are crafted to avoid/self-contain harmful
memory corruptions that they do (e.g. make sure that OOB write
accesses land in in-object kmalloc training space, etc.). If you turn
read accesses in tests into write accesses, memory corruptions caused
by the earlier tests will crash the kernel or the latter tests.

That's why I run the store-only test when this mode is "sync"
In case of "async/asymm" as you mention since it reports "after",
there will be memory corruption.

But in case of sync, when the MTE fault happens, it doesn't
write to memory so, I think it's fine.

Does it not? I thought MTE gets disabled and we return from the fault
handler and let the write instruction execute. But my memory on this
is foggy. And I don't have a setup right now to test.

Right. when fault is hit the MTE gets disabled.
But in kasan_test_c.c -- See the KUNIT_EXPECT_KASAN_FAIL,
It re-enables for next test by calling kasan_enable_hw_tags().

So, the store-only with sync mode seems fine unless we wouldn't care
about failure (no fault happen) which makes memory corruption.

However, I'm not sure writing the seperate testcases for store-only
is right or now since
same tests which only are different of return value check will be
duplicate and half of these always skipped (when duplicate for
store-only, former should be skip and vice versa).

Thanks.

--
Sincerely,
Yeoreum Yun