From f00bb757ed630affc951691ddaff206039cbb7ee Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Tue, 20 Aug 2024 03:23:51 -0700 Subject: [PATCH] selftests/bpf: fix to avoid __msg tag de-duplication by clang __msg, __regex and __xlated tags are based on __attribute__((btf_decl_tag("..."))) annotations. Clang de-duplicates such annotations, e.g. the following two sequences of tags are identical in final BTF: /* seq A */ /* seq B */ __tag("foo") __tag("foo") __tag("bar") __tag("bar") __tag("foo") Fix this by adding a unique suffix for each tag using __COUNTER__ pre-processor macro. E.g. here is a new definition for __msg: #define __msg(msg) \ __attribute__((btf_decl_tag("comment:test_expect_msg=" XSTR(__COUNTER__) "=" msg))) Using this definition the "seq A" from example above is translated to BTF as follows: [..] DECL_TAG 'comment:test_expect_msg=0=foo' type_id=X component_idx=-1 [..] DECL_TAG 'comment:test_expect_msg=1=bar' type_id=X component_idx=-1 [..] DECL_TAG 'comment:test_expect_msg=2=foo' type_id=X component_idx=-1 Surprisingly, this bug affects a single existing test: verifier_spill_fill/old_stack_misc_vs_cur_ctx_ptr, where sequence of identical messages was expected in the log. Fixes: 537c3f66eac1 ("selftests/bpf: add generic BPF program tester-loader") Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/r/20240820102357.3372779-4-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/progs/bpf_misc.h | 15 +++--- .../selftests/bpf/progs/verifier_spill_fill.c | 8 ++-- tools/testing/selftests/bpf/test_loader.c | 47 ++++++++++++++----- 3 files changed, 48 insertions(+), 22 deletions(-) diff --git a/tools/testing/selftests/bpf/progs/bpf_misc.h b/tools/testing/selftests/bpf/progs/bpf_misc.h index a225cd87897c41..4f10297437341b 100644 --- a/tools/testing/selftests/bpf/progs/bpf_misc.h +++ b/tools/testing/selftests/bpf/progs/bpf_misc.h @@ -2,6 +2,9 @@ #ifndef __BPF_MISC_H__ #define __BPF_MISC_H__ +#define XSTR(s) STR(s) +#define STR(s) #s + /* This set of attributes controls behavior of the * test_loader.c:test_loader__run_subtests(). * @@ -68,15 +71,15 @@ * Several __arch_* annotations could be specified at once. * When test case is not run on current arch it is marked as skipped. */ -#define __msg(msg) __attribute__((btf_decl_tag("comment:test_expect_msg=" msg))) -#define __regex(regex) __attribute__((btf_decl_tag("comment:test_expect_regex=" regex))) -#define __xlated(msg) __attribute__((btf_decl_tag("comment:test_expect_xlated=" msg))) +#define __msg(msg) __attribute__((btf_decl_tag("comment:test_expect_msg=" XSTR(__COUNTER__) "=" msg))) +#define __regex(regex) __attribute__((btf_decl_tag("comment:test_expect_regex=" XSTR(__COUNTER__) "=" regex))) +#define __xlated(msg) __attribute__((btf_decl_tag("comment:test_expect_xlated=" XSTR(__COUNTER__) "=" msg))) #define __failure __attribute__((btf_decl_tag("comment:test_expect_failure"))) #define __success __attribute__((btf_decl_tag("comment:test_expect_success"))) #define __description(desc) __attribute__((btf_decl_tag("comment:test_description=" desc))) -#define __msg_unpriv(msg) __attribute__((btf_decl_tag("comment:test_expect_msg_unpriv=" msg))) -#define __regex_unpriv(regex) __attribute__((btf_decl_tag("comment:test_expect_regex_unpriv=" regex))) -#define __xlated_unpriv(msg) __attribute__((btf_decl_tag("comment:test_expect_xlated_unpriv=" msg))) +#define __msg_unpriv(msg) __attribute__((btf_decl_tag("comment:test_expect_msg_unpriv=" XSTR(__COUNTER__) "=" msg))) +#define __regex_unpriv(regex) __attribute__((btf_decl_tag("comment:test_expect_regex_unpriv=" XSTR(__COUNTER__) "=" regex))) +#define __xlated_unpriv(msg) __attribute__((btf_decl_tag("comment:test_expect_xlated_unpriv=" XSTR(__COUNTER__) "=" msg))) #define __failure_unpriv __attribute__((btf_decl_tag("comment:test_expect_failure_unpriv"))) #define __success_unpriv __attribute__((btf_decl_tag("comment:test_expect_success_unpriv"))) #define __log_level(lvl) __attribute__((btf_decl_tag("comment:test_log_level="#lvl))) diff --git a/tools/testing/selftests/bpf/progs/verifier_spill_fill.c b/tools/testing/selftests/bpf/progs/verifier_spill_fill.c index 9d288ec7a1689d..671d9f415dbf7b 100644 --- a/tools/testing/selftests/bpf/progs/verifier_spill_fill.c +++ b/tools/testing/selftests/bpf/progs/verifier_spill_fill.c @@ -1213,10 +1213,10 @@ __success __log_level(2) * - once for path entry - label 2; * - once for path entry - label 1 - label 2. */ -__msg("r1 = *(u64 *)(r10 -8)") -__msg("exit") -__msg("r1 = *(u64 *)(r10 -8)") -__msg("exit") +__msg("8: (79) r1 = *(u64 *)(r10 -8)") +__msg("9: (95) exit") +__msg("from 2 to 7") +__msg("8: safe") __msg("processed 11 insns") __flag(BPF_F_TEST_STATE_FREQ) __naked void old_stack_misc_vs_cur_ctx_ptr(void) diff --git a/tools/testing/selftests/bpf/test_loader.c b/tools/testing/selftests/bpf/test_loader.c index f5f5d16ac5505d..c604a82e03c439 100644 --- a/tools/testing/selftests/bpf/test_loader.c +++ b/tools/testing/selftests/bpf/test_loader.c @@ -215,6 +215,35 @@ static void update_flags(int *flags, int flag, bool clear) *flags |= flag; } +/* Matches a string of form '[^=]=.*' and returns it's suffix. + * Used to parse btf_decl_tag values. + * Such values require unique prefix because compiler does not add + * same __attribute__((btf_decl_tag(...))) twice. + * Test suite uses two-component tags for such cases: + * + * __COUNTER__ '=' + * + * For example, two consecutive __msg tags '__msg("foo") __msg("foo")' + * would be encoded as: + * + * [18] DECL_TAG 'comment:test_expect_msg=0=foo' type_id=15 component_idx=-1 + * [19] DECL_TAG 'comment:test_expect_msg=1=foo' type_id=15 component_idx=-1 + * + * And the purpose of this function is to extract 'foo' from the above. + */ +static const char *skip_dynamic_pfx(const char *s, const char *pfx) +{ + const char *msg; + + if (strncmp(s, pfx, strlen(pfx)) != 0) + return NULL; + msg = s + strlen(pfx); + msg = strchr(msg, '='); + if (!msg) + return NULL; + return msg + 1; +} + enum arch { ARCH_X86_64 = 0x1, ARCH_ARM64 = 0x2, @@ -290,38 +319,32 @@ static int parse_test_spec(struct test_loader *tester, } else if (strcmp(s, TEST_TAG_AUXILIARY_UNPRIV) == 0) { spec->auxiliary = true; spec->mode_mask |= UNPRIV; - } else if (str_has_pfx(s, TEST_TAG_EXPECT_MSG_PFX)) { - msg = s + sizeof(TEST_TAG_EXPECT_MSG_PFX) - 1; + } else if ((msg = skip_dynamic_pfx(s, TEST_TAG_EXPECT_MSG_PFX))) { err = push_msg(msg, NULL, &spec->priv.expect_msgs); if (err) goto cleanup; spec->mode_mask |= PRIV; - } else if (str_has_pfx(s, TEST_TAG_EXPECT_MSG_PFX_UNPRIV)) { - msg = s + sizeof(TEST_TAG_EXPECT_MSG_PFX_UNPRIV) - 1; + } else if ((msg = skip_dynamic_pfx(s, TEST_TAG_EXPECT_MSG_PFX_UNPRIV))) { err = push_msg(msg, NULL, &spec->unpriv.expect_msgs); if (err) goto cleanup; spec->mode_mask |= UNPRIV; - } else if (str_has_pfx(s, TEST_TAG_EXPECT_REGEX_PFX)) { - msg = s + sizeof(TEST_TAG_EXPECT_REGEX_PFX) - 1; + } else if ((msg = skip_dynamic_pfx(s, TEST_TAG_EXPECT_REGEX_PFX))) { err = push_msg(NULL, msg, &spec->priv.expect_msgs); if (err) goto cleanup; spec->mode_mask |= PRIV; - } else if (str_has_pfx(s, TEST_TAG_EXPECT_REGEX_PFX_UNPRIV)) { - msg = s + sizeof(TEST_TAG_EXPECT_REGEX_PFX_UNPRIV) - 1; + } else if ((msg = skip_dynamic_pfx(s, TEST_TAG_EXPECT_REGEX_PFX_UNPRIV))) { err = push_msg(NULL, msg, &spec->unpriv.expect_msgs); if (err) goto cleanup; spec->mode_mask |= UNPRIV; - } else if (str_has_pfx(s, TEST_TAG_EXPECT_XLATED_PFX)) { - msg = s + sizeof(TEST_TAG_EXPECT_XLATED_PFX) - 1; + } else if ((msg = skip_dynamic_pfx(s, TEST_TAG_EXPECT_XLATED_PFX))) { err = push_msg(msg, NULL, &spec->priv.expect_xlated); if (err) goto cleanup; spec->mode_mask |= PRIV; - } else if (str_has_pfx(s, TEST_TAG_EXPECT_XLATED_PFX_UNPRIV)) { - msg = s + sizeof(TEST_TAG_EXPECT_XLATED_PFX_UNPRIV) - 1; + } else if ((msg = skip_dynamic_pfx(s, TEST_TAG_EXPECT_XLATED_PFX_UNPRIV))) { err = push_msg(msg, NULL, &spec->unpriv.expect_xlated); if (err) goto cleanup;