On 20.02.2024 08:46, David Gow wrote: > On Wed, 14 Feb 2024 at 20:41, Paul Heidekrüger <paul.heidekrueger@xxxxxx> wrote: > > > > Hi! > > > > I was running some KASan tests with kunit.py recently and noticed that > > when KASan is run in hw tags mode, we manually have to add the required > > `mte=on` option to kunit_tool's qemu invocation, as the tests will > > otherwise crash. > > > > To make life easier, I was looking into ways for kunit.py to recognise > > when MTE support was required and set the option automatically. > > > > All solutions I could come up with for having kunit_tool conditionally > > pass `mte=on` to qemu, either entailed duplicate code or required > > parsing of kernel's config file again. I was working under the > > assumption that only after configuring the kernel we would know whether > > the 'mte=on' option was necessary, as CONFIG_ARM64_MTE is not visible > > before. > > > > Only afterwads did I realise that the qemu arm64 config that kunit_tool > > falls back on, uses the `virt` machine, which supports MTE in any case. > > So, could it be as easy as just adding the `mte=on` option to > > kunit_tool's arm64 config? Would this be a welcome addition? > > > > What do you think? > > > > Many thanks, > > Paul > > > > Signed-off-by: Paul Heidekrüger <paul.heidekrueger@xxxxxx> > > --- > > I think this is fine. I'd be a little bit concerned if this were only > supported in newer qemu versions, but it seems to go back to 6.2, so > should be okay. I think it's better to just enable it unconditionally > by default rather than trying to parse the config. > > The KASAN tests seemed to work fine with HW tags in my testing here. I > do wonder if there's a way to make the tests skip themselves if MTE > isn't available: is there a way of doing a runtime check for this? Huh, interesting. Even though "mte=on" isn't set on your side? I get the following output without the MTE patch. ➜ ./tools/testing/kunit/kunit.py run --kunitconfig=mm/kasan/.kunitconfig --arch=arm64 [14:08:11] Configuring KUnit Kernel ... [14:08:11] Building KUnit Kernel ... Populating config with: $ make ARCH=arm64 O=.kunit olddefconfig Building with: $ make ARCH=arm64 O=.kunit --jobs=8 [14:08:23] Starting KUnit Kernel (1/1)... [14:08:23] ============================================================ Running tests with: $ qemu-system-aarch64 -nodefaults -m 1024 -kernel .kunit/arch/arm64/boot/Image.gz -append 'kunit.enable=1 console=ttyAMA0 kunit_shutdown=reboot' -no-reboot -nographic -serial stdio -machine virt -cpu max,pauth-impdef=on [14:08:23] kasan: test: Can't run KASAN tests with KASAN disabled [14:08:23] # kasan: # failed to initialize (-1) [14:08:23] [FAILED] kasan [14:08:23] ============================================================ [14:08:23] Testing complete. Ran 1 tests: failed: 1 [14:08:24] Elapsed time: 12.374s total, 0.001s configuring, 11.937s building, 0.382s running Where the mentioned .kunitconfig has the following options set for KASan. CONFIG_KUNIT=y CONFIG_KUNIT_ALL_TESTS=n CONFIG_FTRACE=y CONFIG_STACK_TRACER=y CONFIG_KASAN=y CONFIG_KASAN_HW_TAGS=y CONFIG_KASAN_KUNIT_TEST=y With the MTE patch from my previous email, everything works just fine. Based on that, do you have a guess why it's working for you and why it isn't for me? > Regardless, this is: > Reviewed-by: David Gow <davidgow@xxxxxxxxxx> Thanks! I'll be sending a non-RFC patch shortly. Many thanks, Paul
