From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 69-171-232-181.mail-mxout.facebook.com (69-171-232-181.mail-mxout.facebook.com [69.171.232.181]) (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 87B863EE1EE for ; Fri, 15 May 2026 22:51:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=69.171.232.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778885478; cv=none; b=XcnHnOXQYgf88E/LJzQgLHsDvXvWX8Nv/7TB3NoQWM2QBeYlf2Um9Z+SH9EbbFW+REGvhpxs/4C0e44Jrf4apewEczFHOX1jvo4Xu73xwtyzjudlLQPDFb1brXZi2/K1iDJ0ikDEzK5rPXZe6ZzfnMoFyXyqny0GWzE2CrS62yk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778885478; c=relaxed/simple; bh=WvWSsDQ0nwCa7yq2rQl8658hoNhX1w/x519UilV1pJk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LrOH3zRjWbLLWhOKRB5QNWABxowmpbTDcM90Zy3IijUDnG+MW12Nm/v0sH6c2hrtOq2934Wkg8ilCjW6bRMxzZtK2VDUDM0+s4o+SqH7t95AyE/8NrVsZRiYMuDbYyo6QIBbX8kURoj7Ydxf+D2Aqae8f+4OY8l9tTswWe0X2jo= 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=69.171.232.181 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 9944EC062F4BB; Fri, 15 May 2026 15:51:11 -0700 (PDT) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Martin KaFai Lau Subject: [PATCH bpf-next v3 7/7] selftests/bpf: Add exception tests with stack arguments Date: Fri, 15 May 2026 15:51:11 -0700 Message-ID: <20260515225111.825224-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260515225035.821178-1-yonghong.song@linux.dev> References: <20260515225035.821178-1-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 tests to verify that bpf_throw() correctly unwinds the stack when the program uses outgoing stack arguments (functions with >5 args). Without the preceding fix, these tests crash the kernel due to corrupted callee-saved register restore. Signed-off-by: Yonghong Song --- .../selftests/bpf/prog_tests/exceptions.c | 7 ++ .../testing/selftests/bpf/progs/exceptions.c | 113 ++++++++++++++++++ 2 files changed, 120 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/exceptions.c b/tools/= testing/selftests/bpf/prog_tests/exceptions.c index e8cbaf2a3e82..3588d6f97fd4 100644 --- a/tools/testing/selftests/bpf/prog_tests/exceptions.c +++ b/tools/testing/selftests/bpf/prog_tests/exceptions.c @@ -85,6 +85,13 @@ static void test_exceptions_success(void) RUN_SUCCESS(exception_bad_assert_range_with, 10); RUN_SUCCESS(exception_throw_from_void_global, 11); =20 + if (skel->rodata->has_stack_arg) { + RUN_SUCCESS(exception_throw_stack_arg, 56); + RUN_SUCCESS(exception_throw_after_stack_arg, 56); + RUN_SUCCESS(exception_throw_subprog_stack_arg, 56); + RUN_SUCCESS(exception_throw_subprog_after_stack_arg, 56); + } + #define RUN_EXT(load_ret, attach_err, expr, msg, after_link) \ { \ LIBBPF_OPTS(bpf_object_open_opts, o, .kernel_log_buf =3D log_buf, \ diff --git a/tools/testing/selftests/bpf/progs/exceptions.c b/tools/testi= ng/selftests/bpf/progs/exceptions.c index 4206f59d7b86..f236aadfe7e6 100644 --- a/tools/testing/selftests/bpf/progs/exceptions.c +++ b/tools/testing/selftests/bpf/progs/exceptions.c @@ -379,4 +379,117 @@ int exception_bad_assert_range_with(struct __sk_buf= f *ctx) return 1; } =20 +#if defined(__TARGET_ARCH_x86) && defined(__BPF_FEATURE_STACK_ARGUMENT) + +const volatile bool has_stack_arg =3D true; + +long arg1 =3D 1, arg2 =3D 2, arg3 =3D 3, arg4 =3D 4, arg5 =3D 5; +long arg6 =3D 6, arg7 =3D 7, arg8 =3D 8, arg9 =3D 9, arg10 =3D 10; + +__noinline static long throwing_many_args(long a, long b, long c, long d= , + long e, long f, long g, long h, + long i, long j) +{ + bpf_throw(a + b + c + d + e + f + g + h + i + j); + return 0; +} + +__noinline int exception_cb_sa(u64 cookie) +{ + return cookie + 1; +} + +SEC("tc") +__exception_cb(exception_cb_sa) +int exception_throw_stack_arg(struct __sk_buff *ctx) +{ + throwing_many_args(arg1, arg2, arg3, arg4, arg5, + arg6, arg7, arg8, arg9, arg10); + return 0; +} + +__noinline static long no_throw_many_args(long a, long b, long c, long d= , + long e, long f, long g, long h, + long i, long j) +{ + return a + b + c + d + e + f + g + h + i + j; +} + +SEC("tc") +__exception_cb(exception_cb_sa) +int exception_throw_after_stack_arg(struct __sk_buff *ctx) +{ + long ret; + + ret =3D no_throw_many_args(arg1, arg2, arg3, arg4, arg5, + arg6, arg7, arg8, arg9, arg10); + if (ret > 0) + bpf_throw(ret); + return 0; +} + +__noinline static long subprog_throw_sa(long val) +{ + throwing_many_args(val, val + 1, val + 2, val + 3, val + 4, + val + 5, val + 6, val + 7, val + 8, val + 9); + return 0; +} + +SEC("tc") +__exception_cb(exception_cb_sa) +int exception_throw_subprog_stack_arg(struct __sk_buff *ctx) +{ + subprog_throw_sa(arg1); + return 0; +} + +__noinline static long subprog_throw_after_sa(long val) +{ + long ret; + + ret =3D no_throw_many_args(val, val + 1, val + 2, val + 3, val + 4, + val + 5, val + 6, val + 7, val + 8, val + 9); + if (ret > 0) + bpf_throw(ret); + return 0; +} + +SEC("tc") +__exception_cb(exception_cb_sa) +int exception_throw_subprog_after_stack_arg(struct __sk_buff *ctx) +{ + subprog_throw_after_sa(arg1); + return 0; +} + +#else + +const volatile bool has_stack_arg =3D false; + +SEC("tc") +int exception_throw_stack_arg(struct __sk_buff *ctx) +{ + return 0; +} + +SEC("tc") +int exception_throw_after_stack_arg(struct __sk_buff *ctx) +{ + return 0; +} + +SEC("tc") +int exception_throw_subprog_stack_arg(struct __sk_buff *ctx) +{ + return 0; +} + +SEC("tc") +int exception_throw_subprog_after_stack_arg(struct __sk_buff *ctx) +{ + return 0; +} + +#endif + char _license[] SEC("license") =3D "GPL"; --=20 2.53.0-Meta