On Thu, Mar 5, 2020 at 1:08 AM Patricia Alfonso <trishalfonso@xxxxxxxxxx> wrote: > > > On Sat, Feb 29, 2020 at 10:29 PM Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > > > > > > > > On Sat, Feb 29, 2020 at 2:23 AM Patricia Alfonso > > > > <trishalfonso@xxxxxxxxxx> wrote: > > > > > > > > > > > > On Thu, Feb 27, 2020 at 3:44 AM 'Patricia Alfonso' via kasan-dev > > > > > > <kasan-dev@xxxxxxxxxxxxxxxx> wrote: > > > > > > > > > > > > > > --- a/tools/testing/kunit/kunit_kernel.py > > > > > > > +++ b/tools/testing/kunit/kunit_kernel.py > > > > > > > @@ -141,7 +141,7 @@ class LinuxSourceTree(object): > > > > > > > return True > > > > > > > > > > > > > > def run_kernel(self, args=[], timeout=None, build_dir=''): > > > > > > > - args.extend(['mem=256M']) > > > > > > > + args.extend(['mem=256M', 'kasan_multi_shot']) > > > > > > > > > > > > This is better done somewhere else (different default value if > > > > > > KASAN_TEST is enabled or something). Or overridden in the KASAN tests. > > > > > > Not everybody uses tools/testing/kunit/kunit_kernel.py and this seems > > > > > > to be a mandatory part now. This means people will always hit this, be > > > > > > confused, figure out they need to flip the value, and only then be > > > > > > able to run kunit+kasan. > > > > > > > > > > > I agree. Is the best way to do this with "bool multishot = > > > > > kasan_save_enable_multi_shot();" and > > > > > "kasan_restore_multi_shot(multishot);" inside test_kasan.c like what > > > > > was done in the tests before? > > > > > > > > This will fix KASAN tests, but not non-KASAN tests running under KUNIT > > > > and triggering KASAN reports. > > > > You set kasan_multi_shot for all KUNIT tests. I am reading this as > > > > that we don't want to abort on the first test that triggered a KASAN > > > > report. Or not? > > > > > > I don't think I understand the question, but let me try to explain my > > > thinking and see if that resonates with you. We know that the KASAN > > > tests will require more than one report, and we want that. For most > > > users, since a KASAN error can cause unexpected kernel behavior for > > > anything after a KASAN error, it is best for just one unexpected KASAN > > > error to be the only error printed to the user, unless they specify > > > kasan-multi-shot. The way I understand it, the way to implement this > > > is to use "bool multishot = kasan_save_enable_multi_shot();" and > > > "kasan_restore_multi_shot(multishot);" around the KASAN tests so that > > > kasan-multi-shot is temporarily enabled for the tests we expect > > > multiple reports. I assume "kasan_restore_multi_shot(multishot);" > > > restores the value to what the user input was so after the KASAN tests > > > are finished, if the user did not specify kasan-multi-shot and an > > > unexpected kasan error is reported, it will print the full report and > > > only that first one. Is this understanding correct? If you have a > > > better way of implementing this or a better expected behavior, I > > > appreciate your thoughts. > > > > Everything you say is correct. > > What I tried to point at is that this new behavior is different from > > the original behavior of your change. Initially you added > > kasan_multi_shot to command line for _all_ kunit tests (not just > > KASAN). The question is: do we want kasan_multi_shot for non-KASAN > > tests or not? > > Ah, yes. I thought your first comment was suggesting I change it from > printing all KASAN tests by default because the intended behavior of > KASAN is to only print the first report. I think I'll pose the > question back to you. Do we want kasan_multi_shot for non-KASAN tests? > For functionality sake, it is only required for the KASAN tests so > this is more of a judgement call for the user experience. Good question. I don't see strong arguments either way. So I guess we can leave the current version (only for kasan tests) and wait when/if somebody has real arguments. I wanted to point to change in behavior and understand if it's intentional/accidental.
