Re: [PATCH bpf-next 3/3] selftests/bpf: Add uretprobe syscall test for regs changes

[Jiri Olsa <olsajiri@gmail.com>]

On Fri, Mar 29, 2024 at 03:34:00PM -0700, Andrii Nakryiko wrote:
> On Wed, Mar 27, 2024 at 3:21 AM Jiri Olsa <jolsa@kernel.org> wrote:
> >
> > Adding test that creates uprobe consumer on uretprobe which changes some
> > of the registers. Making sure the changed registers are propagated to the
> > user space when the ureptobe syscall trampoline is used on x86_64.
> >
> > To be able to do this, adding support to bpf_testmod to create uprobe via
> > new attribute file:
> >   /sys/kernel/bpf_testmod_uprobe
> >
> > This file is expecting file offset and creates related uprobe on current
> > process exe file and removes existing uprobe if offset is 0. The can be
> > only single uprobe at any time.
> >
> > The uprobe has specific consumer that changes registers used in ureprobe
> > syscall trampoline and which are later checked in the test.
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >  .../selftests/bpf/bpf_testmod/bpf_testmod.c   | 119 +++++++++++++++++-
> >  .../selftests/bpf/prog_tests/uprobe_syscall.c |  67 ++++++++++
> >  2 files changed, 185 insertions(+), 1 deletion(-)
> >
> 
> LGTM:
> 
> Acked-by: Andrii Nakryiko <andrii@kernel.org>
> 
> [...]
> 
> >  BTF_KFUNCS_START(bpf_testmod_common_kfunc_ids)
> >  BTF_ID_FLAGS(func, bpf_iter_testmod_seq_new, KF_ITER_NEW)
> >  BTF_ID_FLAGS(func, bpf_iter_testmod_seq_next, KF_ITER_NEXT | KF_RET_NULL)
> > @@ -650,7 +763,10 @@ static int bpf_testmod_init(void)
> >                 return ret;
> >         if (bpf_fentry_test1(0) < 0)
> >                 return -EINVAL;
> > -       return sysfs_create_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file);
> > +       ret = sysfs_create_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file);
> > +       if (ret < 0)
> > +               return ret;
> > +       return register_bpf_testmod_uprobe();
> 
> nit: keep using the same pattern to make adding more actions easier in
> the future:
> 
> ret = register_bpf_testmod_uprobe();
> if (ret < 0)
>     return ret;
> return 0;

ok, will change 

thanks,
jirka

> 
> >  }
> >
> >  static void bpf_testmod_exit(void)
> > @@ -664,6 +780,7 @@ static void bpf_testmod_exit(void)
> >                 msleep(20);
> >
> >         sysfs_remove_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file);
> > +       unregister_bpf_testmod_uprobe();
> >  }
> >
> 
> [...]