Hi Yonghong,
Thank you for your review.
26 July 2024 at 05:11, "Yonghong Song" <yonghong.song@xxxxxxxxx> wrote:
>
> On 7/24/24 5:32 PM, Leon Hwang wrote:
>
> >
> > Add a selftest to confirm the issue, which gets -EINVAL when update
> >
> > attached freplace prog to PROG_ARRAY map, has been fixed.
> >
> > cd tools/testing/selftests/bpf; ./test_progs -t tailcalls
> >
> > 327/25 tailcalls/tailcall_freplace:OK
> >
> > 327 tailcalls:OK
> >
> > Summary: 1/25 PASSED, 0 SKIPPED, 0 FAILED
> >
> > Signed-off-by: Leon Hwang <leon.hwang@xxxxxxxxx>
> >
> > ---
> >
> > .../selftests/bpf/prog_tests/tailcalls.c | 76 ++++++++++++++++++-
> >
> > .../selftests/bpf/progs/tailcall_freplace.c | 33 ++++++++
> >
> > .../testing/selftests/bpf/progs/tc_bpf2bpf.c | 23 ++++++
> >
> > 3 files changed, 131 insertions(+), 1 deletion(-)
> >
> > create mode 100644 tools/testing/selftests/bpf/progs/tailcall_freplace.c
> >
> > create mode 100644 tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
> >
> > diff --git a/tools/testing/selftests/bpf/prog_tests/tailcalls.c b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
> >
> > index e01fabb8cc415..f1145601c0005 100644
> >
> > --- a/tools/testing/selftests/bpf/prog_tests/tailcalls.c
> >
> > +++ b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
> >
> > @@ -5,7 +5,8 @@
> >
> > #include "tailcall_poke.skel.h"
> >
> > #include "tailcall_bpf2bpf_hierarchy2.skel.h"
> >
> > #include "tailcall_bpf2bpf_hierarchy3.skel.h"
> >
> > -
> >
> > +#include "tailcall_freplace.skel.h"
> >
> > +#include "tc_bpf2bpf.skel.h"
> >
> > > /* test_tailcall_1 checks basic functionality by patching multiple locations
> >
> > * in a single program for a single tail call slot with nop->jmp, jmp->nop
> >
> > @@ -1495,6 +1496,77 @@ static void test_tailcall_bpf2bpf_hierarchy_3(void)
> >
> > RUN_TESTS(tailcall_bpf2bpf_hierarchy3);
> >
> > }
> >
> > > +/* test_tailcall_freplace checks that the attached freplace prog is OK to
> >
> > + * update to PROG_ARRAY map.
> >
>
> update the prog_array map.
Ack.
>
> >
> > + */
> >
> > +static void test_tailcall_freplace(void)
> >
> > +{
> >
> > + struct tailcall_freplace *fr_skel = NULL;
> >
> > + struct tc_bpf2bpf *tc_skel = NULL;
> >
> > + struct bpf_link *fr_link = NULL;
> >
> > + int prog_fd, map_fd;
> >
> > + char buff[128] = {};
> >
> > + int err, key;
> >
> > +
> >
> > + LIBBPF_OPTS(bpf_test_run_opts, topts,
> >
> > + .data_in = buff,
> >
> > + .data_size_in = sizeof(buff),
> >
> > + .repeat = 1,
> >
> > + );
> >
> > +
> >
> > + fr_skel = tailcall_freplace__open();
> >
> > + if (!ASSERT_OK_PTR(fr_skel, "open fr_skel"))
> >
>
> if (!ASSERT_OK_PTR(fr_skel, "open fr_skel"))
>
> ==>
>
> if (!ASSERT_OK_PTR(fr_skel, "tailcall_freplace__open"))
>
> Similar for below other ASSERT_* macros.
Ack.
>
> >
> > + goto out;
> >
>
> Let us just do 'return' here.
Ack.
>
> >
> > +
> >
> > + tc_skel = tc_bpf2bpf__open_and_load();
> >
> > + if (!ASSERT_OK_PTR(tc_skel, "open tc_skel"))
> >
> > + goto out;
> >
> > +
> >
> > + prog_fd = bpf_program__fd(tc_skel->progs.entry);
> >
> > + if (!ASSERT_GE(prog_fd, 0, "tc_skel entry prog_id"))
> >
> > + goto out;
> >
>
> ASSERT_GE is not necessary, prog_fd should already be valid.
Ack.
I should read bpf_program__fd() source code before using it.
>
> >
> > +
> >
> > + err = bpf_program__set_attach_target(fr_skel->progs.entry,
> >
> > + prog_fd, "subprog");
> >
> > + if (!ASSERT_OK(err, "set_attach_target"))
> >
> > + goto out;
> >
> > +
> >
> > + err = tailcall_freplace__load(fr_skel);
> >
> > + if (!ASSERT_OK(err, "load fr_skel"))
> >
> > + goto out;
> >
> > +
> >
> > + fr_link = bpf_program__attach_freplace(fr_skel->progs.entry,
> >
> > + prog_fd, "subprog");
> >
> > + if (!ASSERT_OK_PTR(fr_link, "attach_freplace"))
> >
> > + goto out;
> >
> > +
> >
> > + prog_fd = bpf_program__fd(fr_skel->progs.entry);
> >
> > + if (!ASSERT_GE(prog_fd, 0, "fr_skel entry prog_fd"))
> >
> > + goto out;
> >
>
> prog_fd is valid here. No need ASSERT_GE.
Ack.
>
> >
> > +
> >
> > + map_fd = bpf_map__fd(fr_skel->maps.jmp_table);
> >
> > + if (!ASSERT_GE(map_fd, 0, "fr_skel jmp_table map_fd"))
> >
> > + goto out;
> >
>
> map_fd is valid. No need ASSERT_GE.
Ack.
>
> >
> > +
> >
> > + key = 0;
> >
> > + err = bpf_map_update_elem(map_fd, &key, &prog_fd, BPF_ANY);
> >
> > + if (!ASSERT_OK(err, "update jmp_table"))
> >
> > + goto out;
> >
> > +
> >
> > + prog_fd = bpf_program__fd(tc_skel->progs.entry);
> >
> > + if (!ASSERT_GE(prog_fd, 0, "prog_fd"))
> >
> > + goto out;
> >
>
> prog_fd is valid here.
Ack.
>
> >
> > +
> >
> > + err = bpf_prog_test_run_opts(prog_fd, &topts);
> >
> > + ASSERT_OK(err, "test_run");
> >
> > + ASSERT_EQ(topts.retval, 34, "test_run retval");
> >
> > +
> >
> > +out:
> >
> > + bpf_link__destroy(fr_link);
> >
> > + tc_bpf2bpf__destroy(tc_skel);
> >
> > + tailcall_freplace__destroy(fr_skel);
> >
> > +}
> >
> > +
> >
> > void test_tailcalls(void)
> >
> > {
> >
> > if (test__start_subtest("tailcall_1"))
> >
> > @@ -1543,4 +1615,6 @@ void test_tailcalls(void)
> >
> > test_tailcall_bpf2bpf_hierarchy_fentry_entry();
> >
> > test_tailcall_bpf2bpf_hierarchy_2();
> >
> > test_tailcall_bpf2bpf_hierarchy_3();
> >
> > + if (test__start_subtest("tailcall_freplace"))
> >
> > + test_tailcall_freplace();
> >
> > }
> >
> > diff --git a/tools/testing/selftests/bpf/progs/tailcall_freplace.c b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
> >
> > new file mode 100644
> >
> > index 0000000000000..80b5fa386ed9c
> >
> > --- /dev/null
> >
> > +++ b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
> >
> > @@ -0,0 +1,33 @@
> >
> > +// SPDX-License-Identifier: GPL-2.0
> >
> > +
> >
> > +#include <linux/bpf.h>
> >
> > +#include <bpf/bpf_helpers.h>
> >
> > +#include "bpf_legacy.h"
> >
>
> bpf_legacy.h is not needed.
Ack.
>
> >
> > +
> >
> > +struct {
> >
> > + __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
> >
> > + __uint(max_entries, 1);
> >
> > + __uint(key_size, sizeof(__u32));
> >
> > + __uint(value_size, sizeof(__u32));
> >
> > +} jmp_table SEC(".maps");
> >
> > +
> >
> > +int count = 0;
> >
> > +
> >
> > +__noinline
> >
> > +int subprog(struct __sk_buff *skb)
> >
> > +{
> >
> > + count++;
> >
> > +
> >
> > + bpf_tail_call_static(skb, &jmp_table, 0);
> >
> > +
> >
> > + return count;
> >
> > +}
> >
>
> subprog() can be inlined into entry(). This
>
> can avoid confusing vs. tc_bpf2bpf.c.
>
> Better if you can differentiate two 'entry()' function
>
> names, e.g., entry_freplace(), entry_tc(), it can make
>
> it easy for people to understand your change in tailcalls.c.
Indeed. Thanks for your suggestion.
>
> >
> > +
> >
> > +SEC("freplace")
> >
> > +int entry(struct __sk_buff *skb)
> >
> > +{
> >
> > + return subprog(skb);
> >
> > +}
> >
> > +
> >
> > +char __license[] SEC("license") = "GPL";
> >
> > +
> >
> > diff --git a/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
> >
> > new file mode 100644
> >
> > index 0000000000000..4810961554585
> >
> > --- /dev/null
> >
> > +++ b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
> >
> > @@ -0,0 +1,23 @@
> >
> > +// SPDX-License-Identifier: GPL-2.0
> >
> > +
> >
> > +#include <linux/bpf.h>
> >
> > +#include <bpf/bpf_helpers.h>
> >
> > +#include "bpf_legacy.h"
> >
> > +
> >
> > +__noinline
> >
> > +int subprog(struct __sk_buff *skb)
> >
> > +{
> >
> > + volatile int ret = 1;
> >
> > +
> >
> > + asm volatile (""::"r+"(ret));
> >
> > + return ret;
> >
> > +}
> >
> > +
> >
> > +SEC("tc")
> >
> > +int entry(struct __sk_buff *skb)
> >
> > +{
> >
> > + return subprog(skb);
> >
> > +}
> >
> > +
> >
> > +char __license[] SEC("license") = "GPL";
> >
> > +
> >
>
