Re: [PATCH bpf-next v1] selftests/bpf: Refactor cb_refs selftests

["Emil Tsalapatis" <emil@etsalapatis.com>]

On Wed Sep 23, 2026 at 11:07 PM UTC, Ihor Solodrai wrote:
> cb_refs matches verifier messages such as "Unreleased reference id=4
> alloc_insn=3". The ID is allocated from env->id_gen, so it changes
> whenever the verifier assigns another ID earlier in the program.
>
> In the bpf tree commit 71919742c83c ("bpf: Assign lock identity to
> callback map values") gives each callback map value an ID, and the
> nested_cb expectation was changed to id=5.
>
> In the bpf-next tree, commit 5dc1549afac9 ("bpf: Consolidate release
> argument validation") changed leak_prog to expect id=4 from the same
> leak check.
>
> The trees are merged in linux-next, and there leak_prog reports id=5
> and the test fails [1]:
>
>   Expected: Unreleased reference id=4 alloc_insn=3
>   ...
>   Unreleased reference id=5 alloc_insn=33
>
> The ID is incidental. The test checks that the verifier rejects the
> leak and which acquisition leaked.
>
> Convert the test to test_loader, register the test in
> prog_tests/verifier.c and drop unnecessary prog_tests/cb_refs.c file.
>
> [1] https://github.com/kernel-patches/bpf/actions/runs/35923662147/job/107398076527
>
> Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>

Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>

> ---
>  .../selftests/bpf/prog_tests/cb_refs.c        | 48 -------------------
>  .../selftests/bpf/prog_tests/verifier.c       |  3 ++
>  tools/testing/selftests/bpf/progs/cb_refs.c   |  5 ++
>  3 files changed, 8 insertions(+), 48 deletions(-)
>  delete mode 100644 tools/testing/selftests/bpf/prog_tests/cb_refs.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/cb_refs.c b/tools/testing/selftests/bpf/prog_tests/cb_refs.c
> deleted file mode 100644
> index c32c6dab49bc..000000000000
> --- a/tools/testing/selftests/bpf/prog_tests/cb_refs.c
> +++ /dev/null
> @@ -1,48 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -#include "bpf/libbpf.h"
> -#include <test_progs.h>
> -#include <network_helpers.h>
> -
> -#include "cb_refs.skel.h"
> -
> -static char log_buf[1024 * 1024];
> -
> -struct {
> -	const char *prog_name;
> -	const char *err_msg;
> -} cb_refs_tests[] = {
> -	{ "underflow_prog", "R1 type=scalar expected=ptr_, trusted_ptr_, rcu_ptr_" },
> -	{ "leak_prog", "Unreleased reference id=4 alloc_insn=3" }, /* alloc_insn=3{2,3} */
> -	{ "nested_cb", "Unreleased reference id=4 alloc_insn=2" }, /* alloc_insn=2{4,5} */
> -	{ "non_cb_transfer_ref", "Unreleased reference id=4 alloc_insn=1" }, /* alloc_insn=1{1,2} */
> -};
> -
> -void test_cb_refs(void)
> -{
> -	LIBBPF_OPTS(bpf_object_open_opts, opts, .kernel_log_buf = log_buf,
> -						.kernel_log_size = sizeof(log_buf),
> -						.kernel_log_level = 1);
> -	struct bpf_program *prog;
> -	struct cb_refs *skel;
> -	int i;
> -
> -	for (i = 0; i < ARRAY_SIZE(cb_refs_tests); i++) {
> -		LIBBPF_OPTS(bpf_test_run_opts, run_opts,
> -			.data_in = &pkt_v4,
> -			.data_size_in = sizeof(pkt_v4),
> -			.repeat = 1,
> -		);
> -		skel = cb_refs__open_opts(&opts);
> -		if (!ASSERT_OK_PTR(skel, "cb_refs__open_and_load"))
> -			return;
> -		prog = bpf_object__find_program_by_name(skel->obj, cb_refs_tests[i].prog_name);
> -		bpf_program__set_autoload(prog, true);
> -		if (!ASSERT_ERR(cb_refs__load(skel), "cb_refs__load"))
> -			bpf_prog_test_run_opts(bpf_program__fd(prog), &run_opts);
> -		if (!ASSERT_OK_PTR(strstr(log_buf, cb_refs_tests[i].err_msg), "expected error message")) {
> -			fprintf(stderr, "Expected: %s\n", cb_refs_tests[i].err_msg);
> -			fprintf(stderr, "Verifier: %s\n", log_buf);
> -		}
> -		cb_refs__destroy(skel);
> -	}
> -}
> diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c
> index 4f1e1c1cd5ab..8b4be06bb181 100644
> --- a/tools/testing/selftests/bpf/prog_tests/verifier.c
> +++ b/tools/testing/selftests/bpf/prog_tests/verifier.c
> @@ -5,6 +5,7 @@
>  #include "arena_kfunc.skel.h"
>  #include "arena_kfunc_jit.skel.h"
>  #include "cap_helpers.h"
> +#include "cb_refs.skel.h"
>  #include "verifier_aggregate_arg.skel.h"
>  #include "verifier_aggregate_ret.skel.h"
>  #include "verifier_align.skel.h"
> @@ -176,6 +177,8 @@ void test_arena_kfunc(void)                   { RUN_TESTS(arena_kfunc); }
>  
>  void test_arena_kfunc_jit(void)               { RUN_TESTS(arena_kfunc_jit); }
>  
> +void test_cb_refs(void)                       { RUN_TESTS(cb_refs); }
> +
>  void test_verifier_aggregate_arg(void)        { RUN_TESTS(verifier_aggregate_arg); }
>  void test_verifier_aggregate_ret(void)        { RUN_TESTS(verifier_aggregate_ret); }
>  void test_verifier_align(void)                { RUN(verifier_align); }
> diff --git a/tools/testing/selftests/bpf/progs/cb_refs.c b/tools/testing/selftests/bpf/progs/cb_refs.c
> index 5d6fc7f01ebb..d4a691db8a15 100644
> --- a/tools/testing/selftests/bpf/progs/cb_refs.c
> +++ b/tools/testing/selftests/bpf/progs/cb_refs.c
> @@ -2,6 +2,7 @@
>  #include <vmlinux.h>
>  #include <bpf/bpf_tracing.h>
>  #include <bpf/bpf_helpers.h>
> +#include "bpf_misc.h"
>  #include "../test_kmods/bpf_testmod_kfunc.h"
>  
>  struct map_value {
> @@ -24,6 +25,7 @@ static __noinline int cb1(void *map, void *key, void *value, void *ctx)
>  }
>  
>  SEC("?tc")
> +__failure __msg("R1 type=scalar expected=ptr_, trusted_ptr_, rcu_ptr_")
>  int underflow_prog(void *ctx)
>  {
>  	struct prog_test_ref_kfunc *p;
> @@ -47,6 +49,7 @@ static __always_inline int cb2(void *map, void *key, void *value, void *ctx)
>  }
>  
>  SEC("?tc")
> +__failure __msg("Unreleased reference id={{[0-9]+}} alloc_insn=3") /* alloc_insn=3{0,2,3} */
>  int leak_prog(void *ctx)
>  {
>  	struct prog_test_ref_kfunc *p;
> @@ -83,6 +86,7 @@ static __always_inline int cb3(void *map, void *key, void *value, void *ctx)
>  }
>  
>  SEC("?tc")
> +__failure __msg("Unreleased reference id={{[0-9]+}} alloc_insn=2") /* alloc_insn=2{2,4,5} */
>  int nested_cb(void *ctx)
>  {
>  	struct prog_test_ref_kfunc *p;
> @@ -98,6 +102,7 @@ int nested_cb(void *ctx)
>  }
>  
>  SEC("?tc")
> +__failure __msg("Unreleased reference id={{[0-9]+}} alloc_insn=1") /* alloc_insn=1{1,2} */
>  int non_cb_transfer_ref(void *ctx)
>  {
>  	struct prog_test_ref_kfunc *p;