Re: [PATCH] perf test: Skip Sigtrap test for arm+aarch64

[John Garry]

On 17/02/2022 16:45, Marco Elver wrote:
> On Thu, 17 Feb 2022 at 17:28, John Garry <john.garry@xxxxxxxxxx> wrote:

+ Ian, Thomas

> > Skip the Sigtrap test for arm + arm64, same as was done for s390 in
> > commit a840974e96fd ("perf test: Test 73 Sig_trap fails on s390").
> >
> > As described by Will at [0], in the test we get stuck in a loop of handling
> > the HW breakpoint exception and never making progress. GDB handles this
> > by stepping over the faulting instruction, but with perf the kernel is
> > expected to handle the step (which it doesn't for arm).
> >
> > Dmitry made an attempt to get this work, also mentioned in the same thread
> > as [0], which was appreciated. But the best thing to do is skip the test
> > for now.
> >
> > [0] https://lore.kernel.org/linux-perf-users/20220118124343.GC98966@leoy-ThinkPad-X240s/T/#m13b06c39d2a5100d340f009435df6f4d8ee57b5a
> >
> > Fixes: Fixes: 5504f67944484 ("perf test sigtrap: Add basic stress test for sigtrap handling")
> > Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
> >
> > diff --git a/tools/perf/tests/sigtrap.c b/tools/perf/tests/sigtrap.c
> > index 1f147fe6595f..3f0b5c1398b5 100644
> > --- a/tools/perf/tests/sigtrap.c
> > +++ b/tools/perf/tests/sigtrap.c
> > @@ -29,7 +29,8 @@
> >    * Just disable the test for these architectures until these issues are
> >    * resolved.
> >    */
> > -#if defined(__powerpc__) || defined(__s390x__)
> > +#if defined(__powerpc__) || defined(__s390x__) || \
> > +       defined(__arm__) || defined(__aarch64__)
> >   #define BP_ACCOUNT_IS_SUPPORTED 0
> >   #else
> >   #define BP_ACCOUNT_IS_SUPPORTED 1
>
> This is now equivalent to BP_SIGNAL_IS_SUPPORTED
> tools/perf/tests/tests.h -- and different from the original
> BP_ACCOUNT_IS_SUPPORTED (and makes me wonder why
> BP_SIGNAL_IS_SUPPORTED wasn't just used from the beginning). Perhaps
> just use BP_SIGNAL_IS_SUPPORTED.

We currently have BP_ACCOUNT_IS_SUPPORTED defined now in 2x locations:

tests/sigtrap.c
tests/bp_account.c

bp_account works for arm64, and we don't want to skip that test. So, as 
long as the macro meaning is appropriate, we can reuse 
BP_SIGNAL_IS_SUPPORTED for sigtrap.c

Thanks,
John