| Message ID | tencent_6D23FE187408D965E95DFAA858BC7E8C760A@qq.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [bpf-next,v8] selftests/bpf: trace_helpers.c: optimize kallsyms cache | expand |
On Sat, Aug 26, 2023 at 10:46 PM Rong Tao <rtoax@foxmail.com> wrote: > > From: Rong Tao <rongtao@cestc.cn> > > 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. > > Acked-by: Stanislav Fomichev <sdf@google.com> > Signed-off-by: Rong Tao <rongtao@cestc.cn> > --- > v8: 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 + > samples/bpf/offwaketime_user.c | 7 +- > samples/bpf/sampleip_user.c | 9 +- > samples/bpf/spintest_user.c | 7 +- > samples/bpf/task_fd_query_user.c | 13 +- > samples/bpf/trace_event_user.c | 7 +- > .../selftests/bpf/prog_tests/bpf_cookie.c | 7 +- > .../selftests/bpf/prog_tests/fill_link_info.c | 9 +- > .../bpf/prog_tests/get_stack_raw_tp.c | 10 +- > .../bpf/prog_tests/kprobe_multi_test.c | 13 +- > .../prog_tests/kprobe_multi_testmod_test.c | 13 +- > tools/testing/selftests/bpf/trace_helpers.c | 116 ++++++++++++------ > tools/testing/selftests/bpf/trace_helpers.h | 10 +- > 13 files changed, 154 insertions(+), 71 deletions(-) I think we'd better split it into two patches: one for samples/bpf/ and another for tools/testing/selftests/bpf. BTW, why can't we just load it once for all ? IOW, load the kallsyms before we start each individual test, and free it after all tests finish.
On Sun, Aug 27, 2023 at 10:48:44AM +0800, Yafang Shao wrote: > On Sat, Aug 26, 2023 at 10:46 PM Rong Tao <rtoax@foxmail.com> wrote: > > > > From: Rong Tao <rongtao@cestc.cn> > > > > 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. > > > > Acked-by: Stanislav Fomichev <sdf@google.com> > > Signed-off-by: Rong Tao <rongtao@cestc.cn> > > --- > > v8: 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 + > > samples/bpf/offwaketime_user.c | 7 +- > > samples/bpf/sampleip_user.c | 9 +- > > samples/bpf/spintest_user.c | 7 +- > > samples/bpf/task_fd_query_user.c | 13 +- > > samples/bpf/trace_event_user.c | 7 +- > > .../selftests/bpf/prog_tests/bpf_cookie.c | 7 +- > > .../selftests/bpf/prog_tests/fill_link_info.c | 9 +- > > .../bpf/prog_tests/get_stack_raw_tp.c | 10 +- > > .../bpf/prog_tests/kprobe_multi_test.c | 13 +- > > .../prog_tests/kprobe_multi_testmod_test.c | 13 +- > > tools/testing/selftests/bpf/trace_helpers.c | 116 ++++++++++++------ > > tools/testing/selftests/bpf/trace_helpers.h | 10 +- > > 13 files changed, 154 insertions(+), 71 deletions(-) > > I think we'd better split it into two patches: one for samples/bpf/ > and another for tools/testing/selftests/bpf. > > BTW, why can't we just load it once for all ? IOW, load the kallsyms > before we start each individual test, and free it after all tests > finish. there are bpf_testmod tests that unload module so we need fresh symbols after that jirka
On Sat, Aug 26, 2023 at 10:46:19PM +0800, Rong Tao wrote: SNIP > diff --git a/samples/bpf/sampleip_user.c b/samples/bpf/sampleip_user.c > index 9283f47844fb..aec3d557aa6b 100644 > --- a/samples/bpf/sampleip_user.c > +++ b/samples/bpf/sampleip_user.c > @@ -25,6 +25,7 @@ > static int map_fd; > static int nr_cpus; > static long _text_addr; > +struct ksyms *ksyms; > > static void usage(void) > { > @@ -109,7 +110,7 @@ static void print_ip_map(int fd) > qsort(counts, max, sizeof(struct ipcount), count_cmp); > for (i = 0; i < max; i++) { > if (counts[i].ip > _text_addr) { > - sym = ksym_search(counts[i].ip); > + sym = ksym_search(ksyms, counts[i].ip); > if (!sym) { > printf("ksym not found. Is kallsyms loaded?\n"); > continue; > @@ -164,13 +165,14 @@ int main(int argc, char **argv) > } > > /* initialize kernel symbol translation */ > - if (load_kallsyms()) { > + ksyms = load_kallsyms(); if we keep the load_kallsyms/ksym_search/ksym_get_addr functions as described in [1] the samples/bpf would stay untouched apart from the Makefile change jirka [1] https://lore.kernel.org/lkml/ZOjUpt16gcTSGkdl@krava/ > + if (!ksyms) { > fprintf(stderr, "ERROR: loading /proc/kallsyms\n"); > return 2; > } > > /* used to determine whether the address is kernel space */ > - _text_addr = ksym_get_addr("_text"); > + _text_addr = ksym_get_addr(ksyms, "_text"); > if (!_text_addr) { > fprintf(stderr, "ERROR: no '_text' in /proc/kallsyms\n"); > return 3; > @@ -230,5 +232,6 @@ int main(int argc, char **argv) > > free(links); > bpf_object__close(obj); > + free_kallsyms(ksyms); > return error; > } > diff --git a/samples/bpf/spintest_user.c b/samples/bpf/spintest_user.c > index 55971edb1088..db6a3c6d5329 100644 > --- a/samples/bpf/spintest_user.c > +++ b/samples/bpf/spintest_user.c > @@ -16,8 +16,10 @@ int main(int ac, char **argv) > int map_fd, i, j = 0; > char filename[256]; > struct ksym *sym; > + struct ksyms *ksyms; > > - if (load_kallsyms()) { > + ksyms = load_kallsyms(); > + if (!ksyms) { > printf("failed to process /proc/kallsyms\n"); > return 2; > } > @@ -58,7 +60,7 @@ int main(int ac, char **argv) > while (bpf_map_get_next_key(map_fd, &key, &next_key) == 0) { > bpf_map_lookup_elem(map_fd, &next_key, &value); > assert(next_key == value); > - sym = ksym_search(value); > + sym = ksym_search(ksyms, value); > key = next_key; > if (!sym) { > printf("ksym not found. Is kallsyms loaded?\n"); > @@ -80,5 +82,6 @@ int main(int ac, char **argv) > bpf_link__destroy(links[j]); > > bpf_object__close(obj); > + free_kallsyms(ksyms); > return 0; > } > diff --git a/samples/bpf/task_fd_query_user.c b/samples/bpf/task_fd_query_user.c > index 1e61f2180470..6e7710a4a96f 100644 > --- a/samples/bpf/task_fd_query_user.c > +++ b/samples/bpf/task_fd_query_user.c > @@ -315,8 +315,10 @@ int main(int argc, char **argv) > struct bpf_program *prog; > struct bpf_object *obj; > int i = 0, err = -1; > + struct ksyms *ksyms; > > - if (load_kallsyms()) { > + ksyms = load_kallsyms(); > + if (!ksyms) { > printf("failed to process /proc/kallsyms\n"); > return err; > } > @@ -368,22 +370,22 @@ int main(int argc, char **argv) > BPF_FD_TYPE_KRETPROBE, > buf, sizeof(buf))); > CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0, > - ksym_get_addr("bpf_check"), false, > + ksym_get_addr(ksyms, "bpf_check"), false, > BPF_FD_TYPE_KPROBE, > BPF_FD_TYPE_KRETPROBE, > buf, sizeof(buf))); > CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0, > - ksym_get_addr("bpf_check"), false, > + ksym_get_addr(ksyms, "bpf_check"), false, > BPF_FD_TYPE_KPROBE, > BPF_FD_TYPE_KRETPROBE, > NULL, 0)); > CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0, > - ksym_get_addr("bpf_check"), true, > + ksym_get_addr(ksyms, "bpf_check"), true, > BPF_FD_TYPE_KPROBE, > BPF_FD_TYPE_KRETPROBE, > buf, sizeof(buf))); > CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0, > - ksym_get_addr("bpf_check"), true, > + ksym_get_addr(ksyms, "bpf_check"), true, > BPF_FD_TYPE_KPROBE, > BPF_FD_TYPE_KRETPROBE, > 0, 0)); > @@ -419,5 +421,6 @@ int main(int argc, char **argv) > bpf_link__destroy(links[i]); > > bpf_object__close(obj); > + free_kallsyms(ksyms); > return err; > } > diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c > index 9664749bf618..b4822166182f 100644 > --- a/samples/bpf/trace_event_user.c > +++ b/samples/bpf/trace_event_user.c > @@ -23,6 +23,7 @@ static int pid; > static int map_fd[2]; > struct bpf_program *prog; > static bool sys_read_seen, sys_write_seen; > +struct ksyms *ksyms; > > static void print_ksym(__u64 addr) > { > @@ -30,7 +31,7 @@ static void print_ksym(__u64 addr) > > if (!addr) > return; > - sym = ksym_search(addr); > + sym = ksym_search(ksyms, addr); > if (!sym) { > printf("ksym not found. Is kallsyms loaded?\n"); > return; > @@ -303,7 +304,8 @@ int main(int argc, char **argv) > signal(SIGINT, err_exit); > signal(SIGTERM, err_exit); > > - if (load_kallsyms()) { > + ksyms = load_kallsyms(); > + if (!ksyms) { > printf("failed to process /proc/kallsyms\n"); > goto cleanup; > } > @@ -348,5 +350,6 @@ int main(int argc, char **argv) > > cleanup: > bpf_object__close(obj); > + free_kallsyms(ksyms); > err_exit(error); > } > diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c > index 1454cebc262b..26bf1f33b8d5 100644 > --- a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c > +++ b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c > @@ -104,8 +104,10 @@ static void kprobe_multi_link_api_subtest(void) > LIBBPF_OPTS(bpf_link_create_opts, opts); > unsigned long long addrs[8]; > __u64 cookies[8]; > + struct ksyms *ksyms; > > - if (!ASSERT_OK(load_kallsyms(), "load_kallsyms")) > + ksyms = load_kallsyms(); > + if (!ASSERT_OK(ksyms != NULL, "load_kallsyms")) > goto cleanup; > > skel = kprobe_multi__open_and_load(); > @@ -116,7 +118,7 @@ static void kprobe_multi_link_api_subtest(void) > skel->bss->test_cookie = true; > > #define GET_ADDR(__sym, __addr) ({ \ > - __addr = ksym_get_addr(__sym); \ > + __addr = ksym_get_addr(ksyms, __sym); \ > if (!ASSERT_NEQ(__addr, 0, "ksym_get_addr " #__sym)) \ > goto cleanup; \ > }) > @@ -171,6 +173,7 @@ static void kprobe_multi_link_api_subtest(void) > cleanup: > close(link1_fd); > close(link2_fd); > + free_kallsyms(ksyms); > kprobe_multi__destroy(skel); > } > > 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..a134eda17446 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_refresh(NULL); > + if (!ASSERT_OK(ksyms != NULL, "load_kallsyms_refresh")) > goto cleanup; > > - kprobe_addr = ksym_get_addr(KPROBE_FUNC); > + kprobe_addr = ksym_get_addr(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(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(ksyms); > } > diff --git a/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c b/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c > index 858e0575f502..7a5e7741da14 100644 > --- a/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c > +++ b/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c > @@ -9,6 +9,7 @@ > #define MAX_STACK_RAWTP 100 > > static int duration = 0; > +static struct ksyms *ksyms; > > struct get_stack_trace_t { > int pid; > @@ -48,7 +49,7 @@ static void get_stack_print_output(void *ctx, int cpu, void *data, __u32 size) > found = num_stack > 0; > } else { > for (i = 0; i < num_stack; i++) { > - ks = ksym_search(raw_data[i]); > + ks = ksym_search(ksyms, raw_data[i]); > if (ks && (strcmp(ks->name, nonjit_func) == 0)) { > found = true; > break; > @@ -65,7 +66,7 @@ static void get_stack_print_output(void *ctx, int cpu, void *data, __u32 size) > good_kern_stack = num_stack > 0; > } else { > for (i = 0; i < num_stack; i++) { > - ks = ksym_search(e.kern_stack[i]); > + ks = ksym_search(ksyms, e.kern_stack[i]); > if (ks && (strcmp(ks->name, nonjit_func) == 0)) { > good_kern_stack = true; > break; > @@ -112,8 +113,8 @@ void test_get_stack_raw_tp(void) > if (CHECK(!map, "bpf_find_map", "not found\n")) > goto close_prog; > > - err = load_kallsyms(); > - if (CHECK(err < 0, "load_kallsyms", "err %d errno %d\n", err, errno)) > + ksyms = load_kallsyms(); > + if (CHECK(!ksyms, "load_kallsyms", "err %d errno %d\n", err, errno)) > goto close_prog; > > CPU_ZERO(&cpu_set); > @@ -146,4 +147,5 @@ void test_get_stack_raw_tp(void) > bpf_link__destroy(link); > perf_buffer__free(pb); > bpf_object__close(obj); > + free_kallsyms(ksyms); > } > diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c > index 179fe300534f..e902ea50de57 100644 > --- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c > +++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c > @@ -6,6 +6,8 @@ > #include "bpf/libbpf_internal.h" > #include "bpf/hashmap.h" > > +static struct ksyms *ksyms; > + > static void kprobe_multi_test_run(struct kprobe_multi *skel, bool test_return) > { > LIBBPF_OPTS(bpf_test_run_opts, topts); > @@ -89,7 +91,7 @@ static void test_link_api(struct bpf_link_create_opts *opts) > } > > #define GET_ADDR(__sym, __addr) ({ \ > - __addr = ksym_get_addr(__sym); \ > + __addr = ksym_get_addr(ksyms, __sym); \ > if (!ASSERT_NEQ(__addr, 0, "kallsyms load failed for " #__sym)) \ > return; \ > }) > @@ -222,8 +224,8 @@ static void test_attach_api_fails(void) > }; > __u64 cookies[2]; > > - addrs[0] = ksym_get_addr("bpf_fentry_test1"); > - addrs[1] = ksym_get_addr("bpf_fentry_test2"); > + addrs[0] = ksym_get_addr(ksyms, "bpf_fentry_test1"); > + addrs[1] = ksym_get_addr(ksyms, "bpf_fentry_test2"); > > if (!ASSERT_FALSE(!addrs[0] || !addrs[1], "ksym_get_addr")) > goto cleanup; > @@ -463,7 +465,8 @@ void serial_test_kprobe_multi_bench_attach(void) > > void test_kprobe_multi_test(void) > { > - if (!ASSERT_OK(load_kallsyms(), "load_kallsyms")) > + ksyms = load_kallsyms(); > + if (!ASSERT_OK(ksyms != NULL, "load_kallsyms")) > return; > > if (test__start_subtest("skel_api")) > @@ -480,4 +483,6 @@ void test_kprobe_multi_test(void) > test_attach_api_syms(); > if (test__start_subtest("attach_api_fails")) > test_attach_api_fails(); > + > + free_kallsyms(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..69de53db63fd 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"); > @@ -50,11 +52,11 @@ 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"); > + addrs[0] = ksym_get_addr(ksyms, "bpf_testmod_fentry_test1"); > ASSERT_NEQ(addrs[0], 0, "ksym_get_addr"); > - addrs[1] = ksym_get_addr("bpf_testmod_fentry_test2"); > + addrs[1] = ksym_get_addr(ksyms, "bpf_testmod_fentry_test2"); > ASSERT_NEQ(addrs[1], 0, "ksym_get_addr"); > - addrs[2] = ksym_get_addr("bpf_testmod_fentry_test3"); > + addrs[2] = ksym_get_addr(ksyms, "bpf_testmod_fentry_test3"); > ASSERT_NEQ(addrs[2], 0, "ksym_get_addr"); > > opts.addrs = (const unsigned long *) addrs; > @@ -79,11 +81,14 @@ 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_refresh(NULL); > + if (!ASSERT_OK(ksyms != NULL, "load_kallsyms_refresh")) > return; > > if (test__start_subtest("testmod_attach_api_syms")) > test_testmod_attach_api_syms(); > if (test__start_subtest("testmod_attach_api_addrs")) > test_testmod_attach_api_addrs(); > + > + free_kallsyms(ksyms); > } > diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c > index f83d9f65c65b..048522d2ac6e 100644 > --- a/tools/testing/selftests/bpf/trace_helpers.c > +++ b/tools/testing/selftests/bpf/trace_helpers.c > @@ -14,99 +14,143 @@ > #include <linux/limits.h> > #include <libelf.h> > #include <gelf.h> > +#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 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(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(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(ksyms); > + return NULL; > } > > -int load_kallsyms(void) > +struct ksyms *load_kallsyms(void) > { > - /* > - * This is called/used from multiplace places, > - * load symbols just once. > - */ > - if (sym_cnt) > - return 0; > - return load_kallsyms_refresh(); > + return load_kallsyms_refresh(NULL); > } > > -struct ksym *ksym_search(long key) > +struct ksym *ksym_search(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) > +long ksym_get_addr(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; > diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h > index 876f3e711df6..6be64f44dd76 100644 > --- a/tools/testing/selftests/bpf/trace_helpers.h > +++ b/tools/testing/selftests/bpf/trace_helpers.h > @@ -11,12 +11,14 @@ struct ksym { > long addr; > char *name; > }; > +struct ksyms; > > -int load_kallsyms(void); > -int load_kallsyms_refresh(void); > +struct ksyms *load_kallsyms(void); > +struct ksyms *load_kallsyms_refresh(struct ksyms *ksyms); > +void free_kallsyms(struct ksyms *ksyms); > > -struct ksym *ksym_search(long key); > -long ksym_get_addr(const char *name); > +struct ksym *ksym_search(struct ksyms *ksyms, long key); > +long ksym_get_addr(struct ksyms *ksyms, const char *name); > > /* open kallsyms and find addresses on the fly, faster than load + search. */ > int kallsyms_find(const char *sym, unsigned long long *addr); > -- > 2.41.0 >
Hi, jirka. Thanks for your reply. > > @@ -164,13 +165,14 @@ int main(int argc, char **argv) > > } > > > > /* initialize kernel symbol translation */ > > - if (load_kallsyms()) { > > + ksyms = load_kallsyms(); > > if we keep the load_kallsyms/ksym_search/ksym_get_addr functions as described > in [1] the samples/bpf would stay untouched apart from the Makefile change Maybe we should make this modification, wouldn't it be better? After all, not modifying the source code of samples/bpf is not really a reason not to make modifications to load_kallsyms(), what do you think? In addition, if we continue to keep the original ksym_search() interface, the following problems are very difficult to deal with: Source code ksym_search [1] struct ksym *ksym_search(long key) { int start = 0, end = sym_cnt; int result; /* kallsyms not loaded. return NULL */ if (sym_cnt <= 0) return NULL; while (start < end) { size_t mid = start + (end - start) / 2; result = key - syms[mid].addr; if (result < 0) end = mid; else if (result > 0) start = mid + 1; else return &syms[mid]; <<< } if (start >= 1 && syms[start - 1].addr < key && key < syms[start].addr) /* valid ksym */ return &syms[start - 1]; <<< /* out of range. return _stext */ return &syms[0]; <<< } The original ksym_search() interface directly returns the global syms address, which is also dangerous for multi-threading. If we allocate new memory for this, it is not a perfect solution. If we rewrite struct ksym *ksym_search(long key) to struct ksym ksym_search(long key) This also affects the source code in samples/bpf. The same problem exists with ksym_get_addr(). Best wishes, Rong Tao [1] https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/tree/tools/testing/selftests/bpf/trace_helpers.c#n100
On Mon, Aug 28, 2023 at 08:57:21AM +0800, Rong Tao wrote: > Hi, jirka. Thanks for your reply. > > > > @@ -164,13 +165,14 @@ int main(int argc, char **argv) > > > } > > > > > > /* initialize kernel symbol translation */ > > > - if (load_kallsyms()) { > > > + ksyms = load_kallsyms(); > > > > if we keep the load_kallsyms/ksym_search/ksym_get_addr functions as described > > in [1] the samples/bpf would stay untouched apart from the Makefile change > > Maybe we should make this modification, wouldn't it be better? After all, > not modifying the source code of samples/bpf is not really a reason not to > make modifications to load_kallsyms(), what do you think? I think we want separate selftest and samples changes and I don't see other way to do that > > In addition, if we continue to keep the original ksym_search() interface, > the following problems are very difficult to deal with: > > Source code ksym_search [1] > > struct ksym *ksym_search(long key) > { > int start = 0, end = sym_cnt; > int result; > > /* kallsyms not loaded. return NULL */ > if (sym_cnt <= 0) > return NULL; > > while (start < end) { > size_t mid = start + (end - start) / 2; > > result = key - syms[mid].addr; > if (result < 0) > end = mid; > else if (result > 0) > start = mid + 1; > else > return &syms[mid]; <<< > } > > if (start >= 1 && syms[start - 1].addr < key && > key < syms[start].addr) > /* valid ksym */ > return &syms[start - 1]; <<< > > /* out of range. return _stext */ > return &syms[0]; <<< > } > > The original ksym_search() interface directly returns the global syms > address, which is also dangerous for multi-threading. If we allocate new > memory for this, it is not a perfect solution. the assumption was that the original ksym_search touches the global syms allocated before running tests.. then tests that actually need fresh kallsyms data (because of bpf_testmod load/unload) would get their own copy of kallsyms jirka > > If we rewrite > > struct ksym *ksym_search(long key) > > to > struct ksym ksym_search(long key) > > This also affects the source code in samples/bpf. > > The same problem exists with ksym_get_addr(). > > Best wishes, > Rong Tao > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/tree/tools/testing/selftests/bpf/trace_helpers.c#n100 > >
> > Hi, jirka. Thanks for your reply. > > > > > > @@ -164,13 +165,14 @@ int main(int argc, char **argv) > > > > } > > > > > > > > /* initialize kernel symbol translation */ > > > > - if (load_kallsyms()) { > > > > + ksyms = load_kallsyms(); > > > > > > if we keep the load_kallsyms/ksym_search/ksym_get_addr functions as described > > > in [1] the samples/bpf would stay untouched apart from the Makefile change > > > > Maybe we should make this modification, wouldn't it be better? After all, > > not modifying the source code of samples/bpf is not really a reason not to > > make modifications to load_kallsyms(), what do you think? > > I think we want separate selftest and samples changes and I don't see > other way to do that Thanks, jirka, I didn't notice this in the previous discussion, sorry. Let me try to solve this problem. Rong Tao
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/samples/bpf/offwaketime_user.c b/samples/bpf/offwaketime_user.c index 5557b5393642..53c1a6b4ec44 100644 --- a/samples/bpf/offwaketime_user.c +++ b/samples/bpf/offwaketime_user.c @@ -16,6 +16,7 @@ /* counts, stackmap */ static int map_fd[2]; +struct ksyms *ksyms; static void print_ksym(__u64 addr) { @@ -23,7 +24,7 @@ static void print_ksym(__u64 addr) if (!addr) return; - sym = ksym_search(addr); + sym = ksym_search(ksyms, addr); if (!sym) { printf("ksym not found. Is kallsyms loaded?\n"); return; @@ -100,7 +101,8 @@ int main(int argc, char **argv) int delay = 1, i = 0; char filename[256]; - if (load_kallsyms()) { + ksyms = load_kallsyms(); + if (!ksyms) { printf("failed to process /proc/kallsyms\n"); return 2; } @@ -149,5 +151,6 @@ int main(int argc, char **argv) bpf_link__destroy(links[i]); bpf_object__close(obj); + free_kallsyms(ksyms); return 0; } diff --git a/samples/bpf/sampleip_user.c b/samples/bpf/sampleip_user.c index 9283f47844fb..aec3d557aa6b 100644 --- a/samples/bpf/sampleip_user.c +++ b/samples/bpf/sampleip_user.c @@ -25,6 +25,7 @@ static int map_fd; static int nr_cpus; static long _text_addr; +struct ksyms *ksyms; static void usage(void) { @@ -109,7 +110,7 @@ static void print_ip_map(int fd) qsort(counts, max, sizeof(struct ipcount), count_cmp); for (i = 0; i < max; i++) { if (counts[i].ip > _text_addr) { - sym = ksym_search(counts[i].ip); + sym = ksym_search(ksyms, counts[i].ip); if (!sym) { printf("ksym not found. Is kallsyms loaded?\n"); continue; @@ -164,13 +165,14 @@ int main(int argc, char **argv) } /* initialize kernel symbol translation */ - if (load_kallsyms()) { + ksyms = load_kallsyms(); + if (!ksyms) { fprintf(stderr, "ERROR: loading /proc/kallsyms\n"); return 2; } /* used to determine whether the address is kernel space */ - _text_addr = ksym_get_addr("_text"); + _text_addr = ksym_get_addr(ksyms, "_text"); if (!_text_addr) { fprintf(stderr, "ERROR: no '_text' in /proc/kallsyms\n"); return 3; @@ -230,5 +232,6 @@ int main(int argc, char **argv) free(links); bpf_object__close(obj); + free_kallsyms(ksyms); return error; } diff --git a/samples/bpf/spintest_user.c b/samples/bpf/spintest_user.c index 55971edb1088..db6a3c6d5329 100644 --- a/samples/bpf/spintest_user.c +++ b/samples/bpf/spintest_user.c @@ -16,8 +16,10 @@ int main(int ac, char **argv) int map_fd, i, j = 0; char filename[256]; struct ksym *sym; + struct ksyms *ksyms; - if (load_kallsyms()) { + ksyms = load_kallsyms(); + if (!ksyms) { printf("failed to process /proc/kallsyms\n"); return 2; } @@ -58,7 +60,7 @@ int main(int ac, char **argv) while (bpf_map_get_next_key(map_fd, &key, &next_key) == 0) { bpf_map_lookup_elem(map_fd, &next_key, &value); assert(next_key == value); - sym = ksym_search(value); + sym = ksym_search(ksyms, value); key = next_key; if (!sym) { printf("ksym not found. Is kallsyms loaded?\n"); @@ -80,5 +82,6 @@ int main(int ac, char **argv) bpf_link__destroy(links[j]); bpf_object__close(obj); + free_kallsyms(ksyms); return 0; } diff --git a/samples/bpf/task_fd_query_user.c b/samples/bpf/task_fd_query_user.c index 1e61f2180470..6e7710a4a96f 100644 --- a/samples/bpf/task_fd_query_user.c +++ b/samples/bpf/task_fd_query_user.c @@ -315,8 +315,10 @@ int main(int argc, char **argv) struct bpf_program *prog; struct bpf_object *obj; int i = 0, err = -1; + struct ksyms *ksyms; - if (load_kallsyms()) { + ksyms = load_kallsyms(); + if (!ksyms) { printf("failed to process /proc/kallsyms\n"); return err; } @@ -368,22 +370,22 @@ int main(int argc, char **argv) BPF_FD_TYPE_KRETPROBE, buf, sizeof(buf))); CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0, - ksym_get_addr("bpf_check"), false, + ksym_get_addr(ksyms, "bpf_check"), false, BPF_FD_TYPE_KPROBE, BPF_FD_TYPE_KRETPROBE, buf, sizeof(buf))); CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0, - ksym_get_addr("bpf_check"), false, + ksym_get_addr(ksyms, "bpf_check"), false, BPF_FD_TYPE_KPROBE, BPF_FD_TYPE_KRETPROBE, NULL, 0)); CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0, - ksym_get_addr("bpf_check"), true, + ksym_get_addr(ksyms, "bpf_check"), true, BPF_FD_TYPE_KPROBE, BPF_FD_TYPE_KRETPROBE, buf, sizeof(buf))); CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0, - ksym_get_addr("bpf_check"), true, + ksym_get_addr(ksyms, "bpf_check"), true, BPF_FD_TYPE_KPROBE, BPF_FD_TYPE_KRETPROBE, 0, 0)); @@ -419,5 +421,6 @@ int main(int argc, char **argv) bpf_link__destroy(links[i]); bpf_object__close(obj); + free_kallsyms(ksyms); return err; } diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c index 9664749bf618..b4822166182f 100644 --- a/samples/bpf/trace_event_user.c +++ b/samples/bpf/trace_event_user.c @@ -23,6 +23,7 @@ static int pid; static int map_fd[2]; struct bpf_program *prog; static bool sys_read_seen, sys_write_seen; +struct ksyms *ksyms; static void print_ksym(__u64 addr) { @@ -30,7 +31,7 @@ static void print_ksym(__u64 addr) if (!addr) return; - sym = ksym_search(addr); + sym = ksym_search(ksyms, addr); if (!sym) { printf("ksym not found. Is kallsyms loaded?\n"); return; @@ -303,7 +304,8 @@ int main(int argc, char **argv) signal(SIGINT, err_exit); signal(SIGTERM, err_exit); - if (load_kallsyms()) { + ksyms = load_kallsyms(); + if (!ksyms) { printf("failed to process /proc/kallsyms\n"); goto cleanup; } @@ -348,5 +350,6 @@ int main(int argc, char **argv) cleanup: bpf_object__close(obj); + free_kallsyms(ksyms); err_exit(error); } diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c index 1454cebc262b..26bf1f33b8d5 100644 --- a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c +++ b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c @@ -104,8 +104,10 @@ static void kprobe_multi_link_api_subtest(void) LIBBPF_OPTS(bpf_link_create_opts, opts); unsigned long long addrs[8]; __u64 cookies[8]; + struct ksyms *ksyms; - if (!ASSERT_OK(load_kallsyms(), "load_kallsyms")) + ksyms = load_kallsyms(); + if (!ASSERT_OK(ksyms != NULL, "load_kallsyms")) goto cleanup; skel = kprobe_multi__open_and_load(); @@ -116,7 +118,7 @@ static void kprobe_multi_link_api_subtest(void) skel->bss->test_cookie = true; #define GET_ADDR(__sym, __addr) ({ \ - __addr = ksym_get_addr(__sym); \ + __addr = ksym_get_addr(ksyms, __sym); \ if (!ASSERT_NEQ(__addr, 0, "ksym_get_addr " #__sym)) \ goto cleanup; \ }) @@ -171,6 +173,7 @@ static void kprobe_multi_link_api_subtest(void) cleanup: close(link1_fd); close(link2_fd); + free_kallsyms(ksyms); kprobe_multi__destroy(skel); } 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..a134eda17446 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_refresh(NULL); + if (!ASSERT_OK(ksyms != NULL, "load_kallsyms_refresh")) goto cleanup; - kprobe_addr = ksym_get_addr(KPROBE_FUNC); + kprobe_addr = ksym_get_addr(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(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(ksyms); } diff --git a/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c b/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c index 858e0575f502..7a5e7741da14 100644 --- a/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c +++ b/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c @@ -9,6 +9,7 @@ #define MAX_STACK_RAWTP 100 static int duration = 0; +static struct ksyms *ksyms; struct get_stack_trace_t { int pid; @@ -48,7 +49,7 @@ static void get_stack_print_output(void *ctx, int cpu, void *data, __u32 size) found = num_stack > 0; } else { for (i = 0; i < num_stack; i++) { - ks = ksym_search(raw_data[i]); + ks = ksym_search(ksyms, raw_data[i]); if (ks && (strcmp(ks->name, nonjit_func) == 0)) { found = true; break; @@ -65,7 +66,7 @@ static void get_stack_print_output(void *ctx, int cpu, void *data, __u32 size) good_kern_stack = num_stack > 0; } else { for (i = 0; i < num_stack; i++) { - ks = ksym_search(e.kern_stack[i]); + ks = ksym_search(ksyms, e.kern_stack[i]); if (ks && (strcmp(ks->name, nonjit_func) == 0)) { good_kern_stack = true; break; @@ -112,8 +113,8 @@ void test_get_stack_raw_tp(void) if (CHECK(!map, "bpf_find_map", "not found\n")) goto close_prog; - err = load_kallsyms(); - if (CHECK(err < 0, "load_kallsyms", "err %d errno %d\n", err, errno)) + ksyms = load_kallsyms(); + if (CHECK(!ksyms, "load_kallsyms", "err %d errno %d\n", err, errno)) goto close_prog; CPU_ZERO(&cpu_set); @@ -146,4 +147,5 @@ void test_get_stack_raw_tp(void) bpf_link__destroy(link); perf_buffer__free(pb); bpf_object__close(obj); + free_kallsyms(ksyms); } diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c index 179fe300534f..e902ea50de57 100644 --- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c +++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c @@ -6,6 +6,8 @@ #include "bpf/libbpf_internal.h" #include "bpf/hashmap.h" +static struct ksyms *ksyms; + static void kprobe_multi_test_run(struct kprobe_multi *skel, bool test_return) { LIBBPF_OPTS(bpf_test_run_opts, topts); @@ -89,7 +91,7 @@ static void test_link_api(struct bpf_link_create_opts *opts) } #define GET_ADDR(__sym, __addr) ({ \ - __addr = ksym_get_addr(__sym); \ + __addr = ksym_get_addr(ksyms, __sym); \ if (!ASSERT_NEQ(__addr, 0, "kallsyms load failed for " #__sym)) \ return; \ }) @@ -222,8 +224,8 @@ static void test_attach_api_fails(void) }; __u64 cookies[2]; - addrs[0] = ksym_get_addr("bpf_fentry_test1"); - addrs[1] = ksym_get_addr("bpf_fentry_test2"); + addrs[0] = ksym_get_addr(ksyms, "bpf_fentry_test1"); + addrs[1] = ksym_get_addr(ksyms, "bpf_fentry_test2"); if (!ASSERT_FALSE(!addrs[0] || !addrs[1], "ksym_get_addr")) goto cleanup; @@ -463,7 +465,8 @@ void serial_test_kprobe_multi_bench_attach(void) void test_kprobe_multi_test(void) { - if (!ASSERT_OK(load_kallsyms(), "load_kallsyms")) + ksyms = load_kallsyms(); + if (!ASSERT_OK(ksyms != NULL, "load_kallsyms")) return; if (test__start_subtest("skel_api")) @@ -480,4 +483,6 @@ void test_kprobe_multi_test(void) test_attach_api_syms(); if (test__start_subtest("attach_api_fails")) test_attach_api_fails(); + + free_kallsyms(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..69de53db63fd 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"); @@ -50,11 +52,11 @@ 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"); + addrs[0] = ksym_get_addr(ksyms, "bpf_testmod_fentry_test1"); ASSERT_NEQ(addrs[0], 0, "ksym_get_addr"); - addrs[1] = ksym_get_addr("bpf_testmod_fentry_test2"); + addrs[1] = ksym_get_addr(ksyms, "bpf_testmod_fentry_test2"); ASSERT_NEQ(addrs[1], 0, "ksym_get_addr"); - addrs[2] = ksym_get_addr("bpf_testmod_fentry_test3"); + addrs[2] = ksym_get_addr(ksyms, "bpf_testmod_fentry_test3"); ASSERT_NEQ(addrs[2], 0, "ksym_get_addr"); opts.addrs = (const unsigned long *) addrs; @@ -79,11 +81,14 @@ 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_refresh(NULL); + if (!ASSERT_OK(ksyms != NULL, "load_kallsyms_refresh")) return; if (test__start_subtest("testmod_attach_api_syms")) test_testmod_attach_api_syms(); if (test__start_subtest("testmod_attach_api_addrs")) test_testmod_attach_api_addrs(); + + free_kallsyms(ksyms); } diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c index f83d9f65c65b..048522d2ac6e 100644 --- a/tools/testing/selftests/bpf/trace_helpers.c +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -14,99 +14,143 @@ #include <linux/limits.h> #include <libelf.h> #include <gelf.h> +#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 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(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(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(ksyms); + return NULL; } -int load_kallsyms(void) +struct ksyms *load_kallsyms(void) { - /* - * This is called/used from multiplace places, - * load symbols just once. - */ - if (sym_cnt) - return 0; - return load_kallsyms_refresh(); + return load_kallsyms_refresh(NULL); } -struct ksym *ksym_search(long key) +struct ksym *ksym_search(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) +long ksym_get_addr(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; diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h index 876f3e711df6..6be64f44dd76 100644 --- a/tools/testing/selftests/bpf/trace_helpers.h +++ b/tools/testing/selftests/bpf/trace_helpers.h @@ -11,12 +11,14 @@ struct ksym { long addr; char *name; }; +struct ksyms; -int load_kallsyms(void); -int load_kallsyms_refresh(void); +struct ksyms *load_kallsyms(void); +struct ksyms *load_kallsyms_refresh(struct ksyms *ksyms); +void free_kallsyms(struct ksyms *ksyms); -struct ksym *ksym_search(long key); -long ksym_get_addr(const char *name); +struct ksym *ksym_search(struct ksyms *ksyms, long key); +long ksym_get_addr(struct ksyms *ksyms, const char *name); /* open kallsyms and find addresses on the fly, faster than load + search. */ int kallsyms_find(const char *sym, unsigned long long *addr);