Re: hw_breakpoint unit test failures with various architectures/platforms in qemu

[Guenter Roeck]

On 3/5/24 01:05, Huacai Chen wrote:
> Hi, Marco,
>
> On Tue, Mar 5, 2024 at 4:34 AM Marco Elver <elver@xxxxxxxxxx> wrote:
> > On Mon, 4 Mar 2024 at 19:12, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> > > Hi,
> > >
> > > I see a number of failures and tracebacks when running the hw_breakpoint
> > > unit tests on various architectures in qemu. Some examples are below.
> > >
> > > Is this a potential problem with the unit tests, with the hardware,
> > > or with the qemu emulation of that hardware ?
> >
> > The test is testing the accounting logic (allocating/deallocating HW
> > breakpoints), not actually using the breakpoints. That requires that
> > the architecture reports the correct number of HW breakpoints
> > available. It looks like it's not doing that.
> >
> > > In other words, is it worthwhile to look into this further, or would
> > > it make more sense to just disable those tests if they fail on a
> > > given hardware/platform ?
> >
> > It's an arch bug:
> > https://lore.kernel.org/lkml/Ytl9L0Zn1PVuL1cB@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
> >
> > Back then we decided to leave the test as-is, given it's reporting an
> > actual issue. However, since then nothing has changed and the test
> > continues to exist as a reminder the arch code needs fixing. I suspect
> > none of us have the time to get to that soon, so we can either leave
> > things as is, or skip the test on all the broken architectures.
> >
> > No idea what's going on with loongarch.
> LoongArch's problem comes from QEMU, I have tested on real machine.
>
> [    7.222500] KTAP version 1
> [    7.226067] 1..1
> [    7.228795]     KTAP version 1
> [    7.232737]     # Subtest: hw_breakpoint
> [    7.237512]     # module: hw_breakpoint_test
> [    7.237520]     1..9
> [    7.442899]     ok 1 test_one_cpu
> [    7.443912]     ok 2 test_many_cpus
> [    7.451298]     ok 3 test_one_task_on_all_cpus
> [    7.456486]     ok 4 test_two_tasks_on_all_cpus
> [    7.462291]     ok 5 test_one_task_on_one_cpu
> [    7.468293]     ok 6 test_one_task_mixed
> [    7.474405]     ok 7 test_two_tasks_on_one_cpu
> [    7.479884]     ok 8 test_two_tasks_on_one_all_cpus
> [    7.485699]     ok 9 test_task_on_all_and_one_cpu
> [    7.491488] # hw_breakpoint: pass:9 fail:0 skip:0 total:9
> [    7.496985] # Totals: pass:9 fail:0 skip:0 total:9
> [    7.503179] ok 1 hw_breakpoint
>
> Huacai

That is good to know. Thanks a lot for testing!

Guenter