On Sat, Apr 30, 2022 at 11:00:19AM +0800, David Gow wrote:
KUnit tests are not supposed to run on production systems: they may do deliberately illegal things to trigger errors, and have security implications (assertions will often deliberately leak kernel addresses).
Add a new taint type, TAINT_KUNIT to signal that a KUnit test has been run. This will be printed as 'N' (for kuNit, as K, U and T were already taken).
This should discourage people from running KUnit tests on production systems, and to make it easier to tell if tests have been run accidentally (by loading the wrong configuration, etc.)
Signed-off-by: David Gow davidgow@google.com
There is no reason to distinguish kunit from selftests if the result is the same: really make the kernel try really insane stupid things which may crash it or put it into a bad state.
So no, this should be renamed to "TEST_BREAK" as I think outside of selftest and kunit we may grow the kernel to do stupid things outside of that domain and this gives us the flexilibilty to use that in other places as well.
It begs the question if we *should* allow userspace to volunterally say "hey, we are doing really insane things, brace yourself." Why ? Well because selftest has tons of modules. We either then define a macro that adds the taint for them and wrap the module declaration for it, or we expose a syctl to let userspace volunteer to opt-in to seggest we are about to try something stupid with the kernel including loading some dangeerous modules which may not have macros which taint the kernel. That would let selftest taint on *any* selftest. Because we can run all selftests or run one selftest.
Then, if such sysctl is exposed, maybe we should then also use this for example for blktests, fstests, fio tests, etc.
Luis