From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 66-220-144-178.mail-mxout.facebook.com (66-220-144-178.mail-mxout.facebook.com [66.220.144.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EDD1C3128D9 for ; Sun, 5 Apr 2026 17:26:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=66.220.144.178 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775410010; cv=none; b=CyFjdU0YK9Ks1RL8z/jg1y3sys7UH7t4Apizboew20FC7IicoisMV2giXR2h2nqltcNO/cwMrWvnWfPOqkhsJ9MEYnEYt091EhDpBoOYBFOF0EdwpYuVNETbelxC8e2idjbTUDxY07XR5nSYU6riGLNEMuggEOgOD/kw/ORYOp0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775410010; c=relaxed/simple; bh=f5PFtJLdXTsdYlVh713hMms8qwU9VKikO9wJ7EI2tGs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aDQIWkdTn3uih90ltlfiPozHkjlTA4oSiyEUnUyUa+zg+pkyNRJyA2JLzdqPw3Lqd5pIpWXLq63VWgLU6sPI3/AjmWC6+3B3aHOZRDjBPLcNY3FUiZBtOum7+woEgPfb9Qp+cHLILU2KCRHizjOeRbA9BaZsfcil+E7mkkjqavA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev; spf=fail smtp.mailfrom=linux.dev; arc=none smtp.client-ip=66.220.144.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=linux.dev Received: by devvm16039.vll0.facebook.com (Postfix, from userid 128203) id 217C8361E5ED0; Sun, 5 Apr 2026 10:26:37 -0700 (PDT) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , "Jose E . Marchesi" , kernel-team@fb.com, Martin KaFai Lau Subject: [PATCH bpf-next v3 10/11] selftests/bpf: Add negative test for greater-than-8-byte kfunc stack argument Date: Sun, 5 Apr 2026 10:26:37 -0700 Message-ID: <20260405172637.1338457-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260405172505.1329392-1-yonghong.song@linux.dev> References: <20260405172505.1329392-1-yonghong.song@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Add a test that the verifier rejects kfunc calls where a stack argument exceeds 8 bytes (the register-sized slot limit). Signed-off-by: Yonghong Song --- .../selftests/bpf/prog_tests/stack_arg_fail.c | 24 ++++++++++++++ .../selftests/bpf/progs/stack_arg_fail.c | 32 +++++++++++++++++++ .../selftests/bpf/test_kmods/bpf_testmod.c | 7 ++++ .../bpf/test_kmods/bpf_testmod_kfunc.h | 8 +++++ 4 files changed, 71 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/stack_arg_fail= .c create mode 100644 tools/testing/selftests/bpf/progs/stack_arg_fail.c diff --git a/tools/testing/selftests/bpf/prog_tests/stack_arg_fail.c b/to= ols/testing/selftests/bpf/prog_tests/stack_arg_fail.c new file mode 100644 index 000000000000..328a79edee45 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/stack_arg_fail.c @@ -0,0 +1,24 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */ + +#include +#include "stack_arg_fail.skel.h" + +void test_stack_arg_fail(void) +{ + struct stack_arg_fail *skel; + + skel =3D stack_arg_fail__open(); + if (!ASSERT_OK_PTR(skel, "open")) + return; + + if (!skel->rodata->has_stack_arg) { + test__skip(); + goto out; + } + + ASSERT_ERR(stack_arg_fail__load(skel), "load_should_fail"); + +out: + stack_arg_fail__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/stack_arg_fail.c b/tools/t= esting/selftests/bpf/progs/stack_arg_fail.c new file mode 100644 index 000000000000..caa63b6f6a80 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/stack_arg_fail.c @@ -0,0 +1,32 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */ + +#include +#include +#include "../test_kmods/bpf_testmod_kfunc.h" + +#if defined(__BPF_FEATURE_STACK_ARGUMENT) + +const volatile bool has_stack_arg =3D true; + +SEC("tc") +int test_stack_arg_big(struct __sk_buff *skb) +{ + struct prog_test_big_arg s =3D { .a =3D 1, .b =3D 2 }; + + return bpf_kfunc_call_stack_arg_big(1, 2, 3, 4, 5, s); +} + +#else + +const volatile bool has_stack_arg =3D false; + +SEC("tc") +int test_stack_arg_big(struct __sk_buff *skb) +{ + return 0; +} + +#endif + +char _license[] SEC("license") =3D "GPL"; diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools= /testing/selftests/bpf/test_kmods/bpf_testmod.c index 4fcdb13e4a9a..861c564cc330 100644 --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c @@ -881,6 +881,12 @@ __bpf_kfunc u64 bpf_kfunc_call_stack_arg_timer(u64 a= , u64 b, u64 c, u64 d, u64 e return a + b + c + d + e; } =20 +__bpf_kfunc u64 bpf_kfunc_call_stack_arg_big(u64 a, u64 b, u64 c, u64 d,= u64 e, + struct prog_test_big_arg s) +{ + return a + b + c + d + e + s.a + s.b; +} + static struct prog_test_ref_kfunc prog_test_struct =3D { .a =3D 42, .b =3D 108, @@ -1352,6 +1358,7 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_stack_arg_mem) BTF_ID_FLAGS(func, bpf_kfunc_call_stack_arg_iter) BTF_ID_FLAGS(func, bpf_kfunc_call_stack_arg_const_str) BTF_ID_FLAGS(func, bpf_kfunc_call_stack_arg_timer) +BTF_ID_FLAGS(func, bpf_kfunc_call_stack_arg_big) BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_pass1) BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail1) BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail2) diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h b= /tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h index 2c1cb118f886..2a40f80b074a 100644 --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h @@ -50,6 +50,11 @@ struct prog_test_pass2 { } x; }; =20 +struct prog_test_big_arg { + long a; + long b; +}; + struct prog_test_fail1 { void *p; int x; @@ -130,6 +135,9 @@ __u64 bpf_kfunc_call_stack_arg_const_str(__u64 a, __u= 64 b, __u64 c, __u64 d, __u const char *str__str) __ksym; __u64 bpf_kfunc_call_stack_arg_timer(__u64 a, __u64 b, __u64 c, __u64 d,= __u64 e, struct bpf_timer *timer) __ksym; +__u64 bpf_kfunc_call_stack_arg_big(__u64 a, __u64 b, __u64 c, __u64 d, _= _u64 e, + struct prog_test_big_arg s) __ksym; + void bpf_kfunc_call_test_pass_ctx(struct __sk_buff *skb) __ksym; void bpf_kfunc_call_test_pass1(struct prog_test_pass1 *p) __ksym; void bpf_kfunc_call_test_pass2(struct prog_test_pass2 *p) __ksym; --=20 2.52.0