netdev - Re: [PATCH bpf-next] selftests/bpf: ensure core_reloc_kernel is reading test

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Date:   Fri, 22 Nov 2019 10:24:24 -0800
From:   Andrii Nakryiko <andrii.nakryiko@...il.com>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc:     Andrii Nakryiko <andriin@...com>, bpf <bpf@...r.kernel.org>,
        Network Development <netdev@...r.kernel.org>,
        Alexei Starovoitov <ast@...com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Kernel Team <kernel-team@...com>
Subject: Re: [PATCH bpf-next] selftests/bpf: ensure core_reloc_kernel is
 reading test_progs's data only

On Thu, Nov 21, 2019 at 11:27 PM Alexei Starovoitov
<alexei.starovoitov@...il.com> wrote:
>
> On Thu, Nov 21, 2019 at 9:59 AM Andrii Nakryiko <andriin@...com> wrote:
> >
> > test_core_reloc_kernel.c selftest is the only CO-RE test that reads and
> > returns for validation calling thread's information (pid, tgid, comm). Thus it
> > has to make sure that only test_prog's invocations are honored.
> >
> > Fixes: df36e621418b ("selftests/bpf: add CO-RE relocs testing setup")
> > Reported-by: Alexei Starovoitov <ast@...nel.org>
> > Signed-off-by: Andrii Nakryiko <andriin@...com>
> > ---
> >  .../selftests/bpf/prog_tests/core_reloc.c        | 16 +++++++++++-----
> >  .../selftests/bpf/progs/test_core_reloc_kernel.c |  4 ++++
> >  2 files changed, 15 insertions(+), 5 deletions(-)
> >
> > diff --git a/tools/testing/selftests/bpf/prog_tests/core_reloc.c b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
> > index ec9e2fdd6b89..05fe85281ff7 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/core_reloc.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
> > @@ -2,6 +2,7 @@
> >  #include <test_progs.h>
> >  #include "progs/core_reloc_types.h"
> >  #include <sys/mman.h>
> > +#include <sys/syscall.h>
> >
> >  #define STRUCT_TO_CHAR_PTR(struct_name) (const char *)&(struct struct_name)
> >
> > @@ -452,6 +453,7 @@ static struct core_reloc_test_case test_cases[] = {
> >  struct data {
> >         char in[256];
> >         char out[256];
> > +       uint64_t my_pid_tgid;
> >  };
> >
> >  static size_t roundup_page(size_t sz)
> > @@ -471,9 +473,12 @@ void test_core_reloc(void)
> >         struct bpf_map *data_map;
> >         struct bpf_program *prog;
> >         struct bpf_object *obj;
> > +       uint64_t my_pid_tgid;
> >         struct data *data;
> >         void *mmap_data = NULL;
> >
> > +       my_pid_tgid = getpid() | ((uint64_t)syscall(SYS_gettid) << 32);
> > +
> >         for (i = 0; i < ARRAY_SIZE(test_cases); i++) {
> >                 test_case = &test_cases[i];
> >                 if (!test__start_subtest(test_case->case_name))
> > @@ -517,11 +522,6 @@ void test_core_reloc(void)
> >                                 goto cleanup;
> >                 }
> >
> > -               link = bpf_program__attach_raw_tracepoint(prog, tp_name);
> > -               if (CHECK(IS_ERR(link), "attach_raw_tp", "err %ld\n",
> > -                         PTR_ERR(link)))
> > -                       goto cleanup;
> > -
> >                 data_map = bpf_object__find_map_by_name(obj, "test_cor.bss");
> >                 if (CHECK(!data_map, "find_data_map", "data map not found\n"))
> >                         goto cleanup;
> > @@ -537,6 +537,12 @@ void test_core_reloc(void)
> >
> >                 memset(mmap_data, 0, sizeof(*data));
> >                 memcpy(data->in, test_case->input, test_case->input_len);
> > +               data->my_pid_tgid = my_pid_tgid;
> > +
> > +               link = bpf_program__attach_raw_tracepoint(prog, tp_name);
> > +               if (CHECK(IS_ERR(link), "attach_raw_tp", "err %ld\n",
> > +                         PTR_ERR(link)))
> > +                       goto cleanup;
> >
> >                 /* trigger test run */
> >                 usleep(1);
> > diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c b/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c
> > index a4b5e0562ed5..d2fe8f337846 100644
> > --- a/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c
> > +++ b/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c
> > @@ -11,6 +11,7 @@ char _license[] SEC("license") = "GPL";
> >  static volatile struct data {
> >         char in[256];
> >         char out[256];
> > +       uint64_t my_pid_tgid;
> >  } data;
>
> There was a conflict here, since global data support patchset was
> already applied.
> I resolved it and applied to bpf-next.
> Thanks

Ah, right, thanks!