From patchwork Mon Sep 4 01:01:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rong Tao X-Patchwork-Id: 13373392 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4D69B381 for ; Mon, 4 Sep 2023 01:02:07 +0000 (UTC) Received: from out203-205-221-210.mail.qq.com (out203-205-221-210.mail.qq.com [203.205.221.210]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0BF1EA0; Sun, 3 Sep 2023 18:02:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foxmail.com; s=s201512; t=1693789323; bh=wOe7c+2nZWH3wTrLJU0gRDjYnChL8PPmVBbhj5PcaRY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=DEhawkGDJGmxcXnO98K235UiiScTWf0z7U4HbzyulgJniatrXmgdUHjziuOhftFdP wcKltdd69rTVWuCwbtSHYheU/cwda0NpdfXBftKdzwh4HT+8gAp1r40vrJzK9tEAev 1gc576fJ31uPZ5Yl1gZKsupHvU65BKnhw85WoEqI= Received: from RT-NUC.. ([39.156.73.12]) by newxmesmtplogicsvrsza10-0.qq.com (NewEsmtp) with SMTP id 6E8B05F; Mon, 04 Sep 2023 09:01:46 +0800 X-QQ-mid: xmsmtpt1693789311tk4zzuv3s Message-ID: X-QQ-XMAILINFO: OGZxhFXqN7PJYiGJ58v64h1OLPQjYPhHJZq1BbELJaFYcEA+hOajNoBqUoa7ZM +umAUf85nOrmGhDGJOPWf1RBWAvgROdwvc1w6MKYfp0FYumh7WULFUg2EKhAUKhss3YVsou1Dn5Y jSD8JETXoXX3NbxCdGWABJQ0lvI1v/uG2AOnLp0mCmqkW4hFMOZWsEHAHYQAuTu/Dk5Bp7Dvib7s bOUriK50Usu03+AgEaY4Zkhksej+79fDvTHpKyNY8U7AsnexMddN0a8zenkZvAFbF8x8/aLC48nQ kQrulJ1FeLEhV3sZTFU6cHw8KczcBykmc/HL02UOQvEvVyOvo0oQgq7MTO2NNpd/1mNWj56efr0i W7trtJj1lr8EvgG9FlAUP703K7/IuvIts1yWOkEcHnF4gDJvrI4aSlw8gEIhv6imCer1VG7ifcrj vbViyREb3Ua+Va5WzG4kTAz8YYHMG33MtnFcc8mOFx04xQKJi3kq8v6oioUVPe5h+MbqxBbwRVjx Mcq/CPq5or98Cshpw56rj0WWe4h477NOnqR7yrz8QgrCLc7flYwpw0t3xvSA08VZLkjvIGJ1iFzd sp5L6WWEO+ptXrzHfP5XFNE0GJpROJbeEXwW3pSwXxGs5jemR4PTKAVsIrWqPJX0gr5umyXSf1ue HSr22wmMJn9mW7L9DnH8AyW9OPFy55/my8jHRp0LGUn54nODFJ/ZE0t/KeMqFnZo5BHqHR6KOzgx FdCmDwORnlMLDech2Zd+EaAXfSKln8/reAf+HJwQUpZ9PsKXSABU7waCxuSeOwiztpSz1PBoTo+i jl6kuHPCCS/eJv076fw2RbeZCmxfPvTzBqP+7RKZ1EjBbF5/5jtmkXjmM/eAENLLk1Z7Sc8XFxM/ BVmmrTnhoym/OkeZlIGe7crI6zKMoxkhKfpHyJgDRBtnfwkjoHv+OpXIwLL34bA0QemdySnsXcxo /j1rbqqMVevqwvZ3vPDaPw70EbB/oi8B0nWlUToL2XV2E5Lc0MXNxGcWSIMSmM X-QQ-XMRINFO: NS+P29fieYNw95Bth2bWPxk= From: Rong Tao To: olsajiri@gmail.com, andrii@kernel.org, daniel@iogearbox.net, sdf@google.com Cc: Rong Tao , Alexei Starovoitov , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan , Maxime Coquelin , Alexandre Torgue , Yafang Shao , bpf@vger.kernel.org (open list:BPF [GENERAL] (Safe Dynamic Programs and Tools)), linux-kernel@vger.kernel.org (open list), linux-kselftest@vger.kernel.org (open list:KERNEL SELFTEST FRAMEWORK), linux-stm32@st-md-mailman.stormreply.com (moderated list:ARM/STM32 ARCHITECTURE), linux-arm-kernel@lists.infradead.org (moderated list:ARM/STM32 ARCHITECTURE) Subject: [PATCH bpf-next v10 1/2] selftests/bpf: trace_helpers.c: optimize kallsyms cache Date: Mon, 4 Sep 2023 09:01:20 +0800 X-OQ-MSGID: X-Mailer: git-send-email 2.41.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=0.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, HELO_DYNAMIC_IPADDR,RCVD_IN_DNSWL_NONE,RDNS_DYNAMIC,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net From: Rong Tao Static ksyms often have problems because the number of symbols exceeds the MAX_SYMS limit. Like changing the MAX_SYMS from 300000 to 400000 in commit e76a014334a6("selftests/bpf: Bump and validate MAX_SYMS") solves the problem somewhat, but it's not the perfect way. This commit uses dynamic memory allocation, which completely solves the problem caused by the limitation of the number of kallsyms. At the same time, add APIs: load_kallsyms_local() ksym_search_local() ksym_get_addr_local() There are used to solve the problem of selftests/bpf updating kallsyms after attach new symbols during testmod testing. Acked-by: Stanislav Fomichev Signed-off-by: Rong Tao --- v10: Keep the original load_kallsyms(). v9: https://lore.kernel.org/lkml/tencent_254B7015EED7A5D112C45E033DA1822CF107@qq.com/ Add load_kallsyms_local,ksym_search_local,ksym_get_addr_local functions. v8: https://lore.kernel.org/lkml/tencent_6D23FE187408D965E95DFAA858BC7E8C760A@qq.com/ Resolves inter-thread contention for ksyms global variables. v7: https://lore.kernel.org/lkml/tencent_BD6E19C00BF565CD5C36A9A0BD828CFA210A@qq.com/ Fix __must_check macro. v6: https://lore.kernel.org/lkml/tencent_4A09A36F883A06EA428A593497642AF8AF08@qq.com/ Apply libbpf_ensure_mem() v5: https://lore.kernel.org/lkml/tencent_0E9E1A1C0981678D5E7EA9E4BDBA8EE2200A@qq.com/ Release the allocated memory once the load_kallsyms_refresh() upon error given it's dynamically allocated. v4: https://lore.kernel.org/lkml/tencent_59C74613113F0C728524B2A82FE5540A5E09@qq.com/ Make sure most cases we don't need the realloc() path to begin with, and check strdup() return value. v3: https://lore.kernel.org/lkml/tencent_50B4B2622FE7546A5FF9464310650C008509@qq.com/ Do not use structs and judge ksyms__add_symbol function return value. v2: https://lore.kernel.org/lkml/tencent_B655EE5E5D463110D70CD2846AB3262EED09@qq.com/ Do the usual len/capacity scheme here to amortize the cost of realloc, and don't free symbols. v1: https://lore.kernel.org/lkml/tencent_AB461510B10CD484E0B2F62E3754165F2909@qq.com/ --- samples/bpf/Makefile | 4 + .../selftests/bpf/prog_tests/fill_link_info.c | 9 +- .../prog_tests/kprobe_multi_testmod_test.c | 24 ++- tools/testing/selftests/bpf/trace_helpers.c | 137 +++++++++++++----- tools/testing/selftests/bpf/trace_helpers.h | 10 +- 5 files changed, 137 insertions(+), 47 deletions(-) diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 4ccf4236031c..6c707ebcebb9 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -175,6 +175,7 @@ TPROGS_CFLAGS += -I$(srctree)/tools/testing/selftests/bpf/ TPROGS_CFLAGS += -I$(LIBBPF_INCLUDE) TPROGS_CFLAGS += -I$(srctree)/tools/include TPROGS_CFLAGS += -I$(srctree)/tools/perf +TPROGS_CFLAGS += -I$(srctree)/tools/lib TPROGS_CFLAGS += -DHAVE_ATTR_TEST=0 ifdef SYSROOT @@ -314,6 +315,9 @@ XDP_SAMPLE_CFLAGS += -Wall -O2 \ $(obj)/$(XDP_SAMPLE): TPROGS_CFLAGS = $(XDP_SAMPLE_CFLAGS) $(obj)/$(XDP_SAMPLE): $(src)/xdp_sample_user.h $(src)/xdp_sample_shared.h +# Override includes for trace_helpers.o because __must_check won't be defined +# in our include path. +$(obj)/$(TRACE_HELPERS): TPROGS_CFLAGS := $(TPROGS_CFLAGS) -D__must_check= -include $(BPF_SAMPLES_PATH)/Makefile.target diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index 9d768e083714..13e618317c8b 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -302,16 +302,18 @@ void test_fill_link_info(void) { struct test_fill_link_info *skel; int i; + struct ksyms *ksyms; skel = test_fill_link_info__open_and_load(); if (!ASSERT_OK_PTR(skel, "skel_open")) return; /* load kallsyms to compare the addr */ - if (!ASSERT_OK(load_kallsyms_refresh(), "load_kallsyms_refresh")) + ksyms = load_kallsyms_local(); + if (!ASSERT_OK_PTR(ksyms, "load_kallsyms_local")) goto cleanup; - kprobe_addr = ksym_get_addr(KPROBE_FUNC); + kprobe_addr = ksym_get_addr_local(ksyms, KPROBE_FUNC); if (test__start_subtest("kprobe_link_info")) test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KPROBE, false); if (test__start_subtest("kretprobe_link_info")) @@ -329,7 +331,7 @@ void test_fill_link_info(void) qsort(kmulti_syms, KMULTI_CNT, sizeof(kmulti_syms[0]), symbols_cmp_r); for (i = 0; i < KMULTI_CNT; i++) - kmulti_addrs[i] = ksym_get_addr(kmulti_syms[i]); + kmulti_addrs[i] = ksym_get_addr_local(ksyms, kmulti_syms[i]); if (test__start_subtest("kprobe_multi_link_info")) test_kprobe_multi_fill_link_info(skel, false, false); if (test__start_subtest("kretprobe_multi_link_info")) @@ -339,4 +341,5 @@ void test_fill_link_info(void) cleanup: test_fill_link_info__destroy(skel); + free_kallsyms_local(ksyms); } diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_testmod_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_testmod_test.c index 1fbe7e4ac00a..532b05ae2da4 100644 --- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_testmod_test.c +++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_testmod_test.c @@ -4,6 +4,8 @@ #include "trace_helpers.h" #include "bpf/libbpf_internal.h" +static struct ksyms *ksyms; + static void kprobe_multi_testmod_check(struct kprobe_multi *skel) { ASSERT_EQ(skel->bss->kprobe_testmod_test1_result, 1, "kprobe_test1_result"); @@ -50,12 +52,12 @@ static void test_testmod_attach_api_addrs(void) LIBBPF_OPTS(bpf_kprobe_multi_opts, opts); unsigned long long addrs[3]; - addrs[0] = ksym_get_addr("bpf_testmod_fentry_test1"); - ASSERT_NEQ(addrs[0], 0, "ksym_get_addr"); - addrs[1] = ksym_get_addr("bpf_testmod_fentry_test2"); - ASSERT_NEQ(addrs[1], 0, "ksym_get_addr"); - addrs[2] = ksym_get_addr("bpf_testmod_fentry_test3"); - ASSERT_NEQ(addrs[2], 0, "ksym_get_addr"); + addrs[0] = ksym_get_addr_local(ksyms, "bpf_testmod_fentry_test1"); + ASSERT_NEQ(addrs[0], 0, "ksym_get_addr_local"); + addrs[1] = ksym_get_addr_local(ksyms, "bpf_testmod_fentry_test2"); + ASSERT_NEQ(addrs[1], 0, "ksym_get_addr_local"); + addrs[2] = ksym_get_addr_local(ksyms, "bpf_testmod_fentry_test3"); + ASSERT_NEQ(addrs[2], 0, "ksym_get_addr_local"); opts.addrs = (const unsigned long *) addrs; opts.cnt = ARRAY_SIZE(addrs); @@ -79,11 +81,19 @@ static void test_testmod_attach_api_syms(void) void serial_test_kprobe_multi_testmod_test(void) { - if (!ASSERT_OK(load_kallsyms_refresh(), "load_kallsyms_refresh")) + ksyms = load_kallsyms_local(); + if (!ASSERT_OK_PTR(ksyms, "load_kallsyms_local")) return; if (test__start_subtest("testmod_attach_api_syms")) test_testmod_attach_api_syms(); + + ksyms = load_kallsyms_refresh(ksyms); + if (!ASSERT_OK_PTR(ksyms, "load_kallsyms_refresh")) + return; + if (test__start_subtest("testmod_attach_api_addrs")) test_testmod_attach_api_addrs(); + + free_kallsyms_local(ksyms); } diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c index f83d9f65c65b..d64c4ef336e1 100644 --- a/tools/testing/selftests/bpf/trace_helpers.c +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -14,104 +14,171 @@ #include #include #include +#include "bpf/libbpf_internal.h" #define TRACEFS_PIPE "/sys/kernel/tracing/trace_pipe" #define DEBUGFS_PIPE "/sys/kernel/debug/tracing/trace_pipe" -#define MAX_SYMS 400000 -static struct ksym syms[MAX_SYMS]; -static int sym_cnt; +struct ksyms { + struct ksym *syms; + size_t sym_cap; + size_t sym_cnt; +}; + +static struct ksyms *ksyms; + +static int ksyms__add_symbol(struct ksyms *ksyms, const char *name, + unsigned long addr) +{ + void *tmp; + + tmp = strdup(name); + if (!tmp) + return -ENOMEM; + ksyms->syms[ksyms->sym_cnt].addr = addr; + ksyms->syms[ksyms->sym_cnt].name = tmp; + + ksyms->sym_cnt++; + + return 0; +} + +void free_kallsyms_local(struct ksyms *ksyms) +{ + unsigned int i; + + if (!ksyms) + return; + + if (!ksyms->syms) { + free(ksyms); + return; + } + + for (i = 0; i < ksyms->sym_cnt; i++) + free(ksyms->syms[i].name); + free(ksyms->syms); + free(ksyms); +} static int ksym_cmp(const void *p1, const void *p2) { return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr; } -int load_kallsyms_refresh(void) +struct ksyms *load_kallsyms_refresh(struct ksyms *ksyms) { FILE *f; char func[256], buf[256]; char symbol; void *addr; - int i = 0; + int ret; - sym_cnt = 0; + /* flush kallsyms, free the previously allocated dynamic memory */ + free_kallsyms_local(ksyms); f = fopen("/proc/kallsyms", "r"); if (!f) - return -ENOENT; + return NULL; + + ksyms = calloc(1, sizeof(struct ksyms)); + if (!ksyms) + return NULL; while (fgets(buf, sizeof(buf), f)) { if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3) break; if (!addr) continue; - if (i >= MAX_SYMS) - return -EFBIG; - syms[i].addr = (long) addr; - syms[i].name = strdup(func); - i++; + ret = libbpf_ensure_mem((void **) &ksyms->syms, &ksyms->sym_cap, + sizeof(struct ksym), ksyms->sym_cnt + 1); + if (ret) + goto error; + ret = ksyms__add_symbol(ksyms, func, (unsigned long)addr); + if (ret) + goto error; } fclose(f); - sym_cnt = i; - qsort(syms, sym_cnt, sizeof(struct ksym), ksym_cmp); - return 0; + qsort(ksyms->syms, ksyms->sym_cnt, sizeof(struct ksym), ksym_cmp); + return ksyms; + +error: + free_kallsyms_local(ksyms); + return NULL; +} + +struct ksyms *load_kallsyms_local(void) +{ + return load_kallsyms_refresh(NULL); } int load_kallsyms(void) { - /* - * This is called/used from multiplace places, - * load symbols just once. - */ - if (sym_cnt) - return 0; - return load_kallsyms_refresh(); + if (!ksyms) + ksyms = load_kallsyms_local(); + return ksyms ? 0 : 1; } -struct ksym *ksym_search(long key) +struct ksym *ksym_search_local(struct ksyms *ksyms, long key) { - int start = 0, end = sym_cnt; + int start = 0, end = ksyms->sym_cnt; int result; + if (!ksyms) + return NULL; + /* kallsyms not loaded. return NULL */ - if (sym_cnt <= 0) + if (ksyms->sym_cnt <= 0) return NULL; while (start < end) { size_t mid = start + (end - start) / 2; - result = key - syms[mid].addr; + result = key - ksyms->syms[mid].addr; if (result < 0) end = mid; else if (result > 0) start = mid + 1; else - return &syms[mid]; + return &ksyms->syms[mid]; } - if (start >= 1 && syms[start - 1].addr < key && - key < syms[start].addr) + if (start >= 1 && ksyms->syms[start - 1].addr < key && + key < ksyms->syms[start].addr) /* valid ksym */ - return &syms[start - 1]; + return &ksyms->syms[start - 1]; /* out of range. return _stext */ - return &syms[0]; + return &ksyms->syms[0]; } -long ksym_get_addr(const char *name) +struct ksym *ksym_search(long key) +{ + if (!ksyms) + return NULL; + return ksym_search_local(ksyms, key); +} + +long ksym_get_addr_local(struct ksyms *ksyms, const char *name) { int i; - for (i = 0; i < sym_cnt; i++) { - if (strcmp(syms[i].name, name) == 0) - return syms[i].addr; + for (i = 0; i < ksyms->sym_cnt; i++) { + if (strcmp(ksyms->syms[i].name, name) == 0) + return ksyms->syms[i].addr; } return 0; } +long ksym_get_addr(const char *name) +{ + if (!ksyms) + return 0; + return ksym_get_addr_local(ksyms, name); +} + /* open kallsyms and read symbol addresses on the fly. Without caching all symbols, * this is faster than load + find. */ diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h index 876f3e711df6..1449a107240c 100644 --- a/tools/testing/selftests/bpf/trace_helpers.h +++ b/tools/testing/selftests/bpf/trace_helpers.h @@ -11,13 +11,19 @@ struct ksym { long addr; char *name; }; +struct ksyms; int load_kallsyms(void); -int load_kallsyms_refresh(void); - struct ksym *ksym_search(long key); long ksym_get_addr(const char *name); +struct ksyms *load_kallsyms_local(void); +struct ksym *ksym_search_local(struct ksyms *ksyms, long key); +long ksym_get_addr_local(struct ksyms *ksyms, const char *name); + +struct ksyms *load_kallsyms_refresh(struct ksyms *ksyms); +void free_kallsyms_local(struct ksyms *ksyms); + /* open kallsyms and find addresses on the fly, faster than load + search. */ int kallsyms_find(const char *sym, unsigned long long *addr);