ASAN reported a memory leak in bpf_get_ksyms(): it allocates a struct ksyms internally and never frees it. Moe struct ksyms to trace_helpers.h and return it from the bpf_get_ksyms(), giving ownership to the caller. Add filtered_syms and filtered_cnt fields to the ksyms to hold the filtered array of symbols, previously returned by bpf_get_ksyms(). Fixup the call sites: kprobe_multi_test and bench_trigger. Signed-off-by: Ihor Solodrai --- .../selftests/bpf/benchs/bench_trigger.c | 9 ++++---- .../bpf/prog_tests/kprobe_multi_test.c | 12 ++++------ tools/testing/selftests/bpf/trace_helpers.c | 23 ++++++++++--------- tools/testing/selftests/bpf/trace_helpers.h | 11 +++++++-- 4 files changed, 30 insertions(+), 25 deletions(-) diff --git a/tools/testing/selftests/bpf/benchs/bench_trigger.c b/tools/testing/selftests/bpf/benchs/bench_trigger.c index aeec9edd3851..7231b88cf21a 100644 --- a/tools/testing/selftests/bpf/benchs/bench_trigger.c +++ b/tools/testing/selftests/bpf/benchs/bench_trigger.c @@ -230,8 +230,7 @@ static void trigger_fentry_setup(void) static void attach_ksyms_all(struct bpf_program *empty, bool kretprobe) { LIBBPF_OPTS(bpf_kprobe_multi_opts, opts); - char **syms = NULL; - size_t cnt = 0; + struct ksyms *ksyms = NULL; /* Some recursive functions will be skipped in * bpf_get_ksyms -> skip_entry, as they can introduce sufficient @@ -241,13 +240,13 @@ static void attach_ksyms_all(struct bpf_program *empty, bool kretprobe) * So, don't run the kprobe-multi-all and kretprobe-multi-all on * a debug kernel. */ - if (bpf_get_ksyms(&syms, &cnt, true)) { + if (bpf_get_ksyms(&ksyms, true)) { fprintf(stderr, "failed to get ksyms\n"); exit(1); } - opts.syms = (const char **) syms; - opts.cnt = cnt; + opts.syms = (const char **)ksyms->filtered_syms; + opts.cnt = ksyms->filtered_cnt; opts.retprobe = kretprobe; /* attach empty to all the kernel functions except bpf_get_numa_node_id. */ if (!bpf_program__attach_kprobe_multi_opts(empty, NULL, &opts)) { 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 9caef222e528..f81dcd609ee9 100644 --- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c +++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c @@ -456,25 +456,23 @@ static void test_kprobe_multi_bench_attach(bool kernel) { LIBBPF_OPTS(bpf_kprobe_multi_opts, opts); struct kprobe_multi_empty *skel = NULL; - char **syms = NULL; - size_t cnt = 0; + struct ksyms *ksyms = NULL; - if (!ASSERT_OK(bpf_get_ksyms(&syms, &cnt, kernel), "bpf_get_ksyms")) + if (!ASSERT_OK(bpf_get_ksyms(&ksyms, kernel), "bpf_get_ksyms")) return; skel = kprobe_multi_empty__open_and_load(); if (!ASSERT_OK_PTR(skel, "kprobe_multi_empty__open_and_load")) goto cleanup; - opts.syms = (const char **) syms; - opts.cnt = cnt; + opts.syms = (const char **)ksyms->filtered_syms; + opts.cnt = ksyms->filtered_cnt; do_bench_test(skel, &opts); cleanup: kprobe_multi_empty__destroy(skel); - if (syms) - free(syms); + free_kallsyms_local(ksyms); } static void test_kprobe_multi_bench_attach_addr(bool kernel) diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c index eeaab7013ca2..0e63daf83ed5 100644 --- a/tools/testing/selftests/bpf/trace_helpers.c +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -24,12 +24,6 @@ #define TRACEFS_PIPE "/sys/kernel/tracing/trace_pipe" #define DEBUGFS_PIPE "/sys/kernel/debug/tracing/trace_pipe" -struct ksyms { - struct ksym *syms; - size_t sym_cap; - size_t sym_cnt; -}; - static struct ksyms *ksyms; static pthread_mutex_t ksyms_mutex = PTHREAD_MUTEX_INITIALIZER; @@ -54,6 +48,8 @@ void free_kallsyms_local(struct ksyms *ksyms) if (!ksyms) return; + free(ksyms->filtered_syms); + if (!ksyms->syms) { free(ksyms); return; @@ -610,7 +606,7 @@ 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) +int bpf_get_ksyms(struct ksyms **ksymsp, bool kernel) { size_t cap = 0, cnt = 0; char *name = NULL, *ksym_name, **syms = NULL; @@ -637,8 +633,10 @@ int bpf_get_ksyms(char ***symsp, size_t *cntp, bool kernel) else f = fopen("/sys/kernel/debug/tracing/available_filter_functions", "r"); - if (!f) + if (!f) { + free_kallsyms_local(ksyms); return -EINVAL; + } map = hashmap__new(symbol_hash, symbol_equal, NULL); if (IS_ERR(map)) { @@ -679,15 +677,18 @@ int bpf_get_ksyms(char ***symsp, size_t *cntp, bool kernel) syms[cnt++] = ksym_name; } - *symsp = syms; - *cntp = cnt; + ksyms->filtered_syms = syms; + ksyms->filtered_cnt = cnt; + *ksymsp = ksyms; error: free(name); fclose(f); hashmap__free(map); - if (err) + if (err) { free(syms); + free_kallsyms_local(ksyms); + } return err; } diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h index a5576b2dfc26..d5bf1433675d 100644 --- a/tools/testing/selftests/bpf/trace_helpers.h +++ b/tools/testing/selftests/bpf/trace_helpers.h @@ -23,7 +23,14 @@ struct ksym { long addr; char *name; }; -struct ksyms; + +struct ksyms { + struct ksym *syms; + size_t sym_cap; + size_t sym_cnt; + char **filtered_syms; + size_t filtered_cnt; +}; typedef int (*ksym_cmp_t)(const void *p1, const void *p2); typedef int (*ksym_search_cmp_t)(const void *p1, const struct ksym *p2); @@ -53,7 +60,7 @@ ssize_t get_rel_offset(uintptr_t addr); int read_build_id(const char *path, char *build_id, size_t size); -int bpf_get_ksyms(char ***symsp, size_t *cntp, bool kernel); +int bpf_get_ksyms(struct ksyms **ksymsp, bool kernel); int bpf_get_addrs(unsigned long **addrsp, size_t *cntp, bool kernel); #endif -- 2.53.0