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From: Yonghong Song <yhs@fb•com>
To: Andrii Nakryiko <andriin@fb•com>, <netdev@vger•kernel.org>
Cc: Alexei Starovoitov <ast@fb•com>,
	Daniel Borkmann <daniel@iogearbox•net>, <kernel-team@fb•com>,
	Yonghong Song <yhs@fb•com>
Subject: [PATCH bpf-next] tools/bpf: fix a selftest test_btf failure
Date: Tue, 5 Feb 2019 14:28:44 -0800	[thread overview]
Message-ID: <20190205222844.2425372-1-yhs@fb.com> (raw)

Commit 9c651127445c ("selftests/btf: add initial BTF dedup tests")
added dedup tests in test_btf.c.
It broke the raw test:
 BTF raw test[71] (func proto (Bad arg name_off)):
    btf_raw_create:2905:FAIL Error getting string #65535, strs_cnt:1

The test itself encodes invalid func_proto parameter name
offset 0xffffFFFF as a negative test for the kernel.
The above commit changed the meaning of that offset and
resulted in a user space error.
  #define NAME_NTH(N) (0xffff0000 | N)
  #define IS_NAME_NTH(X) ((X & 0xffff0000) == 0xffff0000)
  #define GET_NAME_NTH_IDX(X) (X & 0x0000ffff)

Currently, the kernel permits maximum name offset 0xffff.
Set the test name off as 0x0fffFFFF to trigger the kernel
verification failure.

Cc: Andrii Nakryiko <andriin@fb•com>
Fixes: 9c651127445c ("selftests/btf: add initial BTF dedup tests")
Signed-off-by: Yonghong Song <yhs@fb•com>
---
 tools/testing/selftests/bpf/test_btf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/test_btf.c b/tools/testing/selftests/bpf/test_btf.c
index 30c3edde7e07..447acc34db94 100644
--- a/tools/testing/selftests/bpf/test_btf.c
+++ b/tools/testing/selftests/bpf/test_btf.c
@@ -1978,7 +1978,7 @@ static struct btf_raw_test raw_tests[] = {
 		/* void (*)(int a, unsigned int <bad_name_off>) */
 		BTF_FUNC_PROTO_ENC(0, 2),			/* [3] */
 			BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1),
-			BTF_FUNC_PROTO_ARG_ENC(0xffffffff, 2),
+			BTF_FUNC_PROTO_ARG_ENC(0x0fffffff, 2),
 		BTF_END_RAW,
 	},
 	.str_sec = "\0a",
-- 
2.17.1


             reply	other threads:[~2019-02-05 22:29 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-05 22:28 Yonghong Song [this message]
2019-02-06  0:39 ` [PATCH bpf-next] tools/bpf: fix a selftest test_btf failure Andrii Nakryiko
2019-02-06  2:36 ` Alexei Starovoitov
2019-02-06  4:26   ` Yonghong Song

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