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Mon, 28 Jul 2025 00:26:50 -0700 (PDT) Received: from 7950hx ([43.129.244.20]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-31e949bbf7asm4459599a91.9.2025.07.28.00.26.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Jul 2025 00:26:50 -0700 (PDT) From: Menglong Dong X-Google-Original-From: Menglong Dong To: alexei.starovoitov@gmail.com, mhiramat@kernel.org Cc: rostedt@goodmis.org, mathieu.desnoyers@efficios.com, hca@linux.ibm.com, revest@chromium.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH RFC bpf-next v2 2/4] selftests/bpf: move get_ksyms and get_addrs to trace_helpers.c Date: Mon, 28 Jul 2025 15:22:51 +0800 Message-ID: <20250728072637.1035818-3-dongml2@chinatelecom.cn> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250728072637.1035818-1-dongml2@chinatelecom.cn> References: <20250728072637.1035818-1-dongml2@chinatelecom.cn> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" We need to get all the kernel function that can be traced sometimes, so we move the get_syms() and get_addrs() in kprobe_multi_test.c to trace_helpers.c and rename it to bpf_get_ksyms() and bpf_get_addrs(). Signed-off-by: Menglong Dong --- .../bpf/prog_tests/kprobe_multi_test.c | 220 +----------------- tools/testing/selftests/bpf/trace_helpers.c | 214 +++++++++++++++++ tools/testing/selftests/bpf/trace_helpers.h | 3 + 3 files changed, 220 insertions(+), 217 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c b/t= ools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c index e19ef509ebf8..171706e78da8 100644 --- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c +++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c @@ -422,220 +422,6 @@ static void test_unique_match(void) kprobe_multi__destroy(skel); } =20 -static size_t symbol_hash(long key, void *ctx __maybe_unused) -{ - return str_hash((const char *) key); -} - -static bool symbol_equal(long key1, long key2, void *ctx __maybe_unused) -{ - return strcmp((const char *) key1, (const char *) key2) =3D=3D 0; -} - -static bool is_invalid_entry(char *buf, bool kernel) -{ - if (kernel && strchr(buf, '[')) - return true; - if (!kernel && !strchr(buf, '[')) - return true; - return false; -} - -static bool skip_entry(char *name) -{ - /* - * We attach to almost all kernel functions and some of them - * will cause 'suspicious RCU usage' when fprobe is attached - * to them. Filter out the current culprits - arch_cpu_idle - * default_idle and rcu_* functions. - */ - if (!strcmp(name, "arch_cpu_idle")) - return true; - if (!strcmp(name, "default_idle")) - return true; - if (!strncmp(name, "rcu_", 4)) - return true; - if (!strcmp(name, "bpf_dispatcher_xdp_func")) - return true; - if (!strncmp(name, "__ftrace_invalid_address__", - sizeof("__ftrace_invalid_address__") - 1)) - return true; - return false; -} - -/* Do comparision by ignoring '.llvm.' suffixes. */ -static int compare_name(const char *name1, const char *name2) -{ - const char *res1, *res2; - int len1, len2; - - res1 =3D strstr(name1, ".llvm."); - res2 =3D strstr(name2, ".llvm."); - len1 =3D res1 ? res1 - name1 : strlen(name1); - len2 =3D res2 ? res2 - name2 : strlen(name2); - - if (len1 =3D=3D len2) - return strncmp(name1, name2, len1); - if (len1 < len2) - return strncmp(name1, name2, len1) <=3D 0 ? -1 : 1; - return strncmp(name1, name2, len2) >=3D 0 ? 1 : -1; -} - -static int load_kallsyms_compare(const void *p1, const void *p2) -{ - return compare_name(((const struct ksym *)p1)->name, ((const struct ksym = *)p2)->name); -} - -static int search_kallsyms_compare(const void *p1, const struct ksym *p2) -{ - return compare_name(p1, p2->name); -} - -static int get_syms(char ***symsp, size_t *cntp, bool kernel) -{ - size_t cap =3D 0, cnt =3D 0; - char *name =3D NULL, *ksym_name, **syms =3D NULL; - struct hashmap *map; - struct ksyms *ksyms; - struct ksym *ks; - char buf[256]; - FILE *f; - int err =3D 0; - - ksyms =3D load_kallsyms_custom_local(load_kallsyms_compare); - if (!ASSERT_OK_PTR(ksyms, "load_kallsyms_custom_local")) - return -EINVAL; - - /* - * The available_filter_functions contains many duplicates, - * but other than that all symbols are usable in kprobe multi - * interface. - * Filtering out duplicates by using hashmap__add, which won't - * add existing entry. - */ - - if (access("/sys/kernel/tracing/trace", F_OK) =3D=3D 0) - f =3D fopen("/sys/kernel/tracing/available_filter_functions", "r"); - else - f =3D fopen("/sys/kernel/debug/tracing/available_filter_functions", "r"); - - if (!f) - return -EINVAL; - - map =3D hashmap__new(symbol_hash, symbol_equal, NULL); - if (IS_ERR(map)) { - err =3D libbpf_get_error(map); - goto error; - } - - while (fgets(buf, sizeof(buf), f)) { - if (is_invalid_entry(buf, kernel)) - continue; - - free(name); - if (sscanf(buf, "%ms$*[^\n]\n", &name) !=3D 1) - continue; - if (skip_entry(name)) - continue; - - ks =3D search_kallsyms_custom_local(ksyms, name, search_kallsyms_compare= ); - if (!ks) { - err =3D -EINVAL; - goto error; - } - - ksym_name =3D ks->name; - err =3D hashmap__add(map, ksym_name, 0); - if (err =3D=3D -EEXIST) { - err =3D 0; - continue; - } - if (err) - goto error; - - err =3D libbpf_ensure_mem((void **) &syms, &cap, - sizeof(*syms), cnt + 1); - if (err) - goto error; - - syms[cnt++] =3D ksym_name; - } - - *symsp =3D syms; - *cntp =3D cnt; - -error: - free(name); - fclose(f); - hashmap__free(map); - if (err) - free(syms); - return err; -} - -static int get_addrs(unsigned long **addrsp, size_t *cntp, bool kernel) -{ - unsigned long *addr, *addrs, *tmp_addrs; - int err =3D 0, max_cnt, inc_cnt; - char *name =3D NULL; - size_t cnt =3D 0; - char buf[256]; - FILE *f; - - if (access("/sys/kernel/tracing/trace", F_OK) =3D=3D 0) - f =3D fopen("/sys/kernel/tracing/available_filter_functions_addrs", "r"); - else - f =3D fopen("/sys/kernel/debug/tracing/available_filter_functions_addrs"= , "r"); - - if (!f) - return -ENOENT; - - /* In my local setup, the number of entries is 50k+ so Let us initially - * allocate space to hold 64k entries. If 64k is not enough, incrementally - * increase 1k each time. - */ - max_cnt =3D 65536; - inc_cnt =3D 1024; - addrs =3D malloc(max_cnt * sizeof(long)); - if (addrs =3D=3D NULL) { - err =3D -ENOMEM; - goto error; - } - - while (fgets(buf, sizeof(buf), f)) { - if (is_invalid_entry(buf, kernel)) - continue; - - free(name); - if (sscanf(buf, "%p %ms$*[^\n]\n", &addr, &name) !=3D 2) - continue; - if (skip_entry(name)) - continue; - - if (cnt =3D=3D max_cnt) { - max_cnt +=3D inc_cnt; - tmp_addrs =3D realloc(addrs, max_cnt); - if (!tmp_addrs) { - err =3D -ENOMEM; - goto error; - } - addrs =3D tmp_addrs; - } - - addrs[cnt++] =3D (unsigned long)addr; - } - - *addrsp =3D addrs; - *cntp =3D cnt; - -error: - free(name); - fclose(f); - if (err) - free(addrs); - return err; -} - static void do_bench_test(struct kprobe_multi_empty *skel, struct bpf_kpro= be_multi_opts *opts) { long attach_start_ns, attach_end_ns; @@ -670,7 +456,7 @@ static void test_kprobe_multi_bench_attach(bool kernel) char **syms =3D NULL; size_t cnt =3D 0; =20 - if (!ASSERT_OK(get_syms(&syms, &cnt, kernel), "get_syms")) + if (!ASSERT_OK(bpf_get_ksyms(&syms, &cnt, kernel), "bpf_get_ksyms")) return; =20 skel =3D kprobe_multi_empty__open_and_load(); @@ -696,13 +482,13 @@ static void test_kprobe_multi_bench_attach_addr(bool = kernel) size_t cnt =3D 0; int err; =20 - err =3D get_addrs(&addrs, &cnt, kernel); + err =3D bpf_get_addrs(&addrs, &cnt, kernel); if (err =3D=3D -ENOENT) { test__skip(); return; } =20 - if (!ASSERT_OK(err, "get_addrs")) + if (!ASSERT_OK(err, "bpf_get_addrs")) return; =20 skel =3D kprobe_multi_empty__open_and_load(); diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/se= lftests/bpf/trace_helpers.c index 81943c6254e6..d24baf244d1f 100644 --- a/tools/testing/selftests/bpf/trace_helpers.c +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -17,6 +17,7 @@ #include #include #include +#include "bpf/hashmap.h" #include "bpf/libbpf_internal.h" =20 #define TRACEFS_PIPE "/sys/kernel/tracing/trace_pipe" @@ -519,3 +520,216 @@ void read_trace_pipe(void) { read_trace_pipe_iter(trace_pipe_cb, NULL, 0); } + +static size_t symbol_hash(long key, void *ctx __maybe_unused) +{ + return str_hash((const char *) key); +} + +static bool symbol_equal(long key1, long key2, void *ctx __maybe_unused) +{ + return strcmp((const char *) key1, (const char *) key2) =3D=3D 0; +} + +static bool is_invalid_entry(char *buf, bool kernel) +{ + if (kernel && strchr(buf, '[')) + return true; + if (!kernel && !strchr(buf, '[')) + return true; + return false; +} + +static bool skip_entry(char *name) +{ + /* + * We attach to almost all kernel functions and some of them + * will cause 'suspicious RCU usage' when fprobe is attached + * to them. Filter out the current culprits - arch_cpu_idle + * default_idle and rcu_* functions. + */ + if (!strcmp(name, "arch_cpu_idle")) + return true; + if (!strcmp(name, "default_idle")) + return true; + if (!strncmp(name, "rcu_", 4)) + return true; + if (!strcmp(name, "bpf_dispatcher_xdp_func")) + return true; + if (!strncmp(name, "__ftrace_invalid_address__", + sizeof("__ftrace_invalid_address__") - 1)) + return true; + return false; +} + +/* Do comparison by ignoring '.llvm.' suffixes. */ +static int compare_name(const char *name1, const char *name2) +{ + const char *res1, *res2; + int len1, len2; + + res1 =3D strstr(name1, ".llvm."); + res2 =3D strstr(name2, ".llvm."); + len1 =3D res1 ? res1 - name1 : strlen(name1); + len2 =3D res2 ? res2 - name2 : strlen(name2); + + if (len1 =3D=3D len2) + return strncmp(name1, name2, len1); + if (len1 < len2) + return strncmp(name1, name2, len1) <=3D 0 ? -1 : 1; + return strncmp(name1, name2, len2) >=3D 0 ? 1 : -1; +} + +static int load_kallsyms_compare(const void *p1, const void *p2) +{ + return compare_name(((const struct ksym *)p1)->name, ((const struct ksym = *)p2)->name); +} + +static int search_kallsyms_compare(const void *p1, const struct ksym *p2) +{ + return compare_name(p1, p2->name); +} + +int bpf_get_ksyms(char ***symsp, size_t *cntp, bool kernel) +{ + size_t cap =3D 0, cnt =3D 0; + char *name =3D NULL, *ksym_name, **syms =3D NULL; + struct hashmap *map; + struct ksyms *ksyms; + struct ksym *ks; + char buf[256]; + FILE *f; + int err =3D 0; + + ksyms =3D load_kallsyms_custom_local(load_kallsyms_compare); + if (!ksyms) + return -EINVAL; + + /* + * The available_filter_functions contains many duplicates, + * but other than that all symbols are usable to trace. + * Filtering out duplicates by using hashmap__add, which won't + * add existing entry. + */ + + if (access("/sys/kernel/tracing/trace", F_OK) =3D=3D 0) + f =3D fopen("/sys/kernel/tracing/available_filter_functions", "r"); + else + f =3D fopen("/sys/kernel/debug/tracing/available_filter_functions", "r"); + + if (!f) + return -EINVAL; + + map =3D hashmap__new(symbol_hash, symbol_equal, NULL); + if (IS_ERR(map)) { + err =3D libbpf_get_error(map); + goto error; + } + + while (fgets(buf, sizeof(buf), f)) { + if (is_invalid_entry(buf, kernel)) + continue; + + free(name); + if (sscanf(buf, "%ms$*[^\n]\n", &name) !=3D 1) + continue; + if (skip_entry(name)) + continue; + + ks =3D search_kallsyms_custom_local(ksyms, name, search_kallsyms_compare= ); + if (!ks) { + err =3D -EINVAL; + goto error; + } + + ksym_name =3D ks->name; + err =3D hashmap__add(map, ksym_name, 0); + if (err =3D=3D -EEXIST) { + err =3D 0; + continue; + } + if (err) + goto error; + + err =3D libbpf_ensure_mem((void **) &syms, &cap, + sizeof(*syms), cnt + 1); + if (err) + goto error; + + syms[cnt++] =3D ksym_name; + } + + *symsp =3D syms; + *cntp =3D cnt; + +error: + free(name); + fclose(f); + hashmap__free(map); + if (err) + free(syms); + return err; +} + +int bpf_get_addrs(unsigned long **addrsp, size_t *cntp, bool kernel) +{ + unsigned long *addr, *addrs, *tmp_addrs; + int err =3D 0, max_cnt, inc_cnt; + char *name =3D NULL; + size_t cnt =3D 0; + char buf[256]; + FILE *f; + + if (access("/sys/kernel/tracing/trace", F_OK) =3D=3D 0) + f =3D fopen("/sys/kernel/tracing/available_filter_functions_addrs", "r"); + else + f =3D fopen("/sys/kernel/debug/tracing/available_filter_functions_addrs"= , "r"); + + if (!f) + return -ENOENT; + + /* In my local setup, the number of entries is 50k+ so Let us initially + * allocate space to hold 64k entries. If 64k is not enough, incrementally + * increase 1k each time. + */ + max_cnt =3D 65536; + inc_cnt =3D 1024; + addrs =3D malloc(max_cnt * sizeof(long)); + if (addrs =3D=3D NULL) { + err =3D -ENOMEM; + goto error; + } + + while (fgets(buf, sizeof(buf), f)) { + if (is_invalid_entry(buf, kernel)) + continue; + + free(name); + if (sscanf(buf, "%p %ms$*[^\n]\n", &addr, &name) !=3D 2) + continue; + if (skip_entry(name)) + continue; + + if (cnt =3D=3D max_cnt) { + max_cnt +=3D inc_cnt; + tmp_addrs =3D realloc(addrs, max_cnt); + if (!tmp_addrs) { + err =3D -ENOMEM; + goto error; + } + addrs =3D tmp_addrs; + } + + addrs[cnt++] =3D (unsigned long)addr; + } + + *addrsp =3D addrs; + *cntp =3D cnt; + +error: + free(name); + fclose(f); + if (err) + free(addrs); + return err; +} diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/se= lftests/bpf/trace_helpers.h index 2ce873c9f9aa..9437bdd4afa5 100644 --- a/tools/testing/selftests/bpf/trace_helpers.h +++ b/tools/testing/selftests/bpf/trace_helpers.h @@ -41,4 +41,7 @@ ssize_t get_rel_offset(uintptr_t addr); =20 int read_build_id(const char *path, char *build_id, size_t size); =20 +int bpf_get_ksyms(char ***symsp, size_t *cntp, bool kernel); +int bpf_get_addrs(unsigned long **addrsp, size_t *cntp, bool kernel); + #endif --=20 2.50.1