diff options
| -rw-r--r-- | tools/perf/builtin-record.c | 13 | ||||
| -rw-r--r-- | tools/perf/builtin-report.c | 26 | ||||
| -rw-r--r-- | tools/perf/util/event.c | 15 | ||||
| -rw-r--r-- | tools/perf/util/header.c | 8 | ||||
| -rw-r--r-- | tools/perf/util/symbol.c | 48 | ||||
| -rw-r--r-- | tools/perf/util/symbol.h | 3 |
6 files changed, 107 insertions, 6 deletions
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 0974f957b8fa..2ca107f3efdf 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -823,6 +823,19 @@ int cmd_record(int argc, const char **argv, const char *prefix __used) symbol__init(); + if (symbol_conf.kptr_restrict) + pr_warning("WARNING: Kernel address maps " + "(/proc/{kallsyms,modules}) are restricted, " + "check /proc/sys/kernel/kptr_restrict.\n\n" + "Samples in kernel functions may not be resolved " + "if a suitable vmlinux file is not found in the " + "buildid cache or in the vmlinux path.\n\n" + "Samples in kernel modules won't be resolved " + "at all.\n\n" + "If some relocation was applied (e.g. kexec) " + "symbols may be misresolved even with a suitable " + "vmlinux or kallsyms file.\n\n"); + if (no_buildid_cache || no_buildid) disable_buildid_cache(); diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c index 498c6f70a747..99156c35bc62 100644 --- a/tools/perf/builtin-report.c +++ b/tools/perf/builtin-report.c @@ -116,6 +116,9 @@ static int process_sample_event(union perf_event *event, if (al.filtered || (hide_unresolved && al.sym == NULL)) return 0; + if (al.map != NULL) + al.map->dso->hit = 1; + if (perf_session__add_hist_entry(session, &al, sample, evsel)) { pr_debug("problem incrementing symbol period, skipping event\n"); return -1; @@ -249,6 +252,8 @@ static int __cmd_report(void) u64 nr_samples; struct perf_session *session; struct perf_evsel *pos; + struct map *kernel_map; + struct kmap *kernel_kmap; const char *help = "For a higher level overview, try: perf report --sort comm,dso"; signal(SIGINT, sig_handler); @@ -268,6 +273,27 @@ static int __cmd_report(void) if (ret) goto out_delete; + kernel_map = session->host_machine.vmlinux_maps[MAP__FUNCTION]; + kernel_kmap = map__kmap(kernel_map); + if (kernel_map == NULL || + (kernel_map->dso->hit && + (kernel_kmap->ref_reloc_sym == NULL || + kernel_kmap->ref_reloc_sym->addr == 0))) { + const struct dso *kdso = kernel_map->dso; + + ui__warning("Kernel address maps " + "(/proc/{kallsyms,modules}) were restricted, " + "check /proc/sys/kernel/kptr_restrict before " + "running 'perf record'.\n\n%s\n\n" + "Samples in kernel modules can't be resolved " + "as well.\n\n", + RB_EMPTY_ROOT(&kdso->symbols[MAP__FUNCTION]) ? + "As no suitable kallsyms nor vmlinux was found, " + "kernel samples can't be resolved." : + "If some relocation was applied (e.g. kexec) " + "symbols may be misresolved."); + } + if (dump_trace) { perf_session__fprintf_nr_events(session, stdout); goto out_delete; diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c index 6635fcd11ca5..0fe9adf76379 100644 --- a/tools/perf/util/event.c +++ b/tools/perf/util/event.c @@ -553,9 +553,18 @@ static int perf_event__process_kernel_mmap(union perf_event *event, goto out_problem; perf_event__set_kernel_mmap_len(event, machine->vmlinux_maps); - perf_session__set_kallsyms_ref_reloc_sym(machine->vmlinux_maps, - symbol_name, - event->mmap.pgoff); + + /* + * Avoid using a zero address (kptr_restrict) for the ref reloc + * symbol. Effectively having zero here means that at record + * time /proc/sys/kernel/kptr_restrict was non zero. + */ + if (event->mmap.pgoff != 0) { + perf_session__set_kallsyms_ref_reloc_sym(machine->vmlinux_maps, + symbol_name, + event->mmap.pgoff); + } + if (machine__is_default_guest(machine)) { /* * preload dso of guest kernel and modules diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 0717bebc7649..afb0849fe530 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -193,9 +193,13 @@ int build_id_cache__add_s(const char *sbuild_id, const char *debugdir, *linkname = malloc(size), *targetname; int len, err = -1; - if (is_kallsyms) + if (is_kallsyms) { + if (symbol_conf.kptr_restrict) { + pr_debug("Not caching a kptr_restrict'ed /proc/kallsyms\n"); + return 0; + } realname = (char *)name; - else + } else realname = realpath(name, NULL); if (realname == NULL || filename == NULL || linkname == NULL) diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 516876dfbe52..eec196329fd9 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -676,9 +676,30 @@ discard_symbol: rb_erase(&pos->rb_node, root); return count + moved; } +static bool symbol__restricted_filename(const char *filename, + const char *restricted_filename) +{ + bool restricted = false; + + if (symbol_conf.kptr_restrict) { + char *r = realpath(filename, NULL); + + if (r != NULL) { + restricted = strcmp(r, restricted_filename) == 0; + free(r); + return restricted; + } + } + + return restricted; +} + int dso__load_kallsyms(struct dso *dso, const char *filename, struct map *map, symbol_filter_t filter) { + if (symbol__restricted_filename(filename, "/proc/kallsyms")) + return -1; + if (dso__load_all_kallsyms(dso, filename, map) < 0) return -1; @@ -1790,6 +1811,9 @@ static int machine__create_modules(struct machine *machine) modules = path; } + if (symbol__restricted_filename(path, "/proc/modules")) + return -1; + file = fopen(modules, "r"); if (file == NULL) return -1; @@ -2239,6 +2263,9 @@ static u64 machine__get_kernel_start_addr(struct machine *machine) } } + if (symbol__restricted_filename(filename, "/proc/kallsyms")) + return 0; + if (kallsyms__parse(filename, &args, symbol__in_kernel) <= 0) return 0; @@ -2410,6 +2437,25 @@ static int setup_list(struct strlist **list, const char *list_str, return 0; } +static bool symbol__read_kptr_restrict(void) +{ + bool value = false; + + if (geteuid() != 0) { + FILE *fp = fopen("/proc/sys/kernel/kptr_restrict", "r"); + if (fp != NULL) { + char line[8]; + + if (fgets(line, sizeof(line), fp) != NULL) + value = atoi(line) != 0; + + fclose(fp); + } + } + + return value; +} + int symbol__init(void) { const char *symfs; @@ -2456,6 +2502,8 @@ int symbol__init(void) if (symfs != symbol_conf.symfs) free((void *)symfs); + symbol_conf.kptr_restrict = symbol__read_kptr_restrict(); + symbol_conf.initialized = true; return 0; diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h index 242de0101a86..325ee36a9d29 100644 --- a/tools/perf/util/symbol.h +++ b/tools/perf/util/symbol.h @@ -75,7 +75,8 @@ struct symbol_conf { use_callchain, exclude_other, show_cpu_utilization, - initialized; + initialized, + kptr_restrict; const char *vmlinux_name, *kallsyms_name, *source_prefix, |