From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- tools/perf/util/libbfd.c | 660 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 660 insertions(+) create mode 100644 tools/perf/util/libbfd.c (limited to 'tools/perf/util/libbfd.c') diff --git a/tools/perf/util/libbfd.c b/tools/perf/util/libbfd.c new file mode 100644 index 000000000..33dc6158b --- /dev/null +++ b/tools/perf/util/libbfd.c @@ -0,0 +1,660 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "libbfd.h" +#include "annotate.h" +#include "bpf-event.h" +#include "bpf-utils.h" +#include "debug.h" +#include "dso.h" +#include "env.h" +#include "map.h" +#include "srcline.h" +#include "symbol.h" +#include "symbol_conf.h" +#include "util.h" +#include +#ifdef HAVE_LIBBPF_SUPPORT +#include +#include +#include +#endif +#include +#include +#include +#define PACKAGE "perf" +#include + +/* + * Implement addr2line using libbfd. + */ +struct a2l_data { + const char *input; + u64 addr; + + bool found; + const char *filename; + const char *funcname; + unsigned int line; + + bfd *abfd; + asymbol **syms; +}; + +static bool perf_bfd_lock(void *bfd_mutex) +{ + mutex_lock(bfd_mutex); + return true; +} + +static bool perf_bfd_unlock(void *bfd_mutex) +{ + mutex_unlock(bfd_mutex); + return true; +} + +static void perf_bfd_init(void) +{ + static struct mutex bfd_mutex; + + mutex_init_recursive(&bfd_mutex); + + if (bfd_init() != BFD_INIT_MAGIC) { + pr_err("Error initializing libbfd\n"); + return; + } + if (!bfd_thread_init(perf_bfd_lock, perf_bfd_unlock, &bfd_mutex)) + pr_err("Error initializing libbfd threading\n"); +} + +static void ensure_bfd_init(void) +{ + static pthread_once_t bfd_init_once = PTHREAD_ONCE_INIT; + + pthread_once(&bfd_init_once, perf_bfd_init); +} + +static int bfd_error(const char *string) +{ + const char *errmsg; + + errmsg = bfd_errmsg(bfd_get_error()); + fflush(stdout); + + if (string) + pr_debug("%s: %s\n", string, errmsg); + else + pr_debug("%s\n", errmsg); + + return -1; +} + +static int slurp_symtab(bfd *abfd, struct a2l_data *a2l) +{ + long storage; + long symcount; + asymbol **syms; + bool dynamic = false; + + if ((bfd_get_file_flags(abfd) & HAS_SYMS) == 0) + return bfd_error(bfd_get_filename(abfd)); + + storage = bfd_get_symtab_upper_bound(abfd); + if (storage == 0L) { + storage = bfd_get_dynamic_symtab_upper_bound(abfd); + dynamic = true; + } + if (storage < 0L) + return bfd_error(bfd_get_filename(abfd)); + + syms = malloc(storage); + if (dynamic) + symcount = bfd_canonicalize_dynamic_symtab(abfd, syms); + else + symcount = bfd_canonicalize_symtab(abfd, syms); + + if (symcount < 0) { + free(syms); + return bfd_error(bfd_get_filename(abfd)); + } + + a2l->syms = syms; + return 0; +} + +static void find_address_in_section(bfd *abfd, asection *section, void *data) +{ + bfd_vma pc, vma; + bfd_size_type size; + struct a2l_data *a2l = data; + flagword flags; + + if (a2l->found) + return; + +#ifdef bfd_get_section_flags + flags = bfd_get_section_flags(abfd, section); +#else + flags = bfd_section_flags(section); +#endif + if ((flags & SEC_ALLOC) == 0) + return; + + pc = a2l->addr; +#ifdef bfd_get_section_vma + vma = bfd_get_section_vma(abfd, section); +#else + vma = bfd_section_vma(section); +#endif +#ifdef bfd_get_section_size + size = bfd_get_section_size(section); +#else + size = bfd_section_size(section); +#endif + + if (pc < vma || pc >= vma + size) + return; + + a2l->found = bfd_find_nearest_line(abfd, section, a2l->syms, pc - vma, + &a2l->filename, &a2l->funcname, + &a2l->line); + + if (a2l->filename && !strlen(a2l->filename)) + a2l->filename = NULL; +} + +static struct a2l_data *addr2line_init(const char *path) +{ + bfd *abfd; + struct a2l_data *a2l = NULL; + + ensure_bfd_init(); + abfd = bfd_openr(path, NULL); + if (abfd == NULL) + return NULL; + + if (!bfd_check_format(abfd, bfd_object)) + goto out; + + a2l = zalloc(sizeof(*a2l)); + if (a2l == NULL) + goto out; + + a2l->abfd = abfd; + a2l->input = strdup(path); + if (a2l->input == NULL) + goto out; + + if (slurp_symtab(abfd, a2l)) + goto out; + + return a2l; + +out: + if (a2l) { + zfree((char **)&a2l->input); + free(a2l); + } + bfd_close(abfd); + return NULL; +} + +static void addr2line_cleanup(struct a2l_data *a2l) +{ + if (a2l->abfd) + bfd_close(a2l->abfd); + zfree((char **)&a2l->input); + zfree(&a2l->syms); + free(a2l); +} + +static int inline_list__append_dso_a2l(struct dso *dso, + struct inline_node *node, + struct symbol *sym) +{ + struct a2l_data *a2l = dso__a2l(dso); + struct symbol *inline_sym = new_inline_sym(dso, sym, a2l->funcname); + char *srcline = NULL; + + if (a2l->filename) + srcline = srcline_from_fileline(a2l->filename, a2l->line); + + return inline_list__append(inline_sym, srcline, node); +} + +int libbfd__addr2line(const char *dso_name, u64 addr, + char **file, unsigned int *line, struct dso *dso, + bool unwind_inlines, struct inline_node *node, + struct symbol *sym) +{ + int ret = 0; + struct a2l_data *a2l = dso__a2l(dso); + + if (!a2l) { + a2l = addr2line_init(dso_name); + dso__set_a2l(dso, a2l); + } + + if (a2l == NULL) { + if (!symbol_conf.addr2line_disable_warn) + pr_warning("addr2line_init failed for %s\n", dso_name); + return 0; + } + + a2l->addr = addr; + a2l->found = false; + + bfd_map_over_sections(a2l->abfd, find_address_in_section, a2l); + + if (!a2l->found) + return 0; + + if (unwind_inlines) { + int cnt = 0; + + if (node && inline_list__append_dso_a2l(dso, node, sym)) + return 0; + + while (bfd_find_inliner_info(a2l->abfd, &a2l->filename, + &a2l->funcname, &a2l->line) && + cnt++ < MAX_INLINE_NEST) { + + if (a2l->filename && !strlen(a2l->filename)) + a2l->filename = NULL; + + if (node != NULL) { + if (inline_list__append_dso_a2l(dso, node, sym)) + return 0; + // found at least one inline frame + ret = 1; + } + } + } + + if (file) { + *file = a2l->filename ? strdup(a2l->filename) : NULL; + ret = *file ? 1 : 0; + } + + if (line) + *line = a2l->line; + + return ret; +} + +void dso__free_a2l_libbfd(struct dso *dso) +{ + struct a2l_data *a2l = dso__a2l(dso); + + if (!a2l) + return; + + addr2line_cleanup(a2l); + + dso__set_a2l(dso, NULL); +} + +static int bfd_symbols__cmpvalue(const void *a, const void *b) +{ + const asymbol *as = *(const asymbol **)a, *bs = *(const asymbol **)b; + + if (bfd_asymbol_value(as) != bfd_asymbol_value(bs)) + return bfd_asymbol_value(as) - bfd_asymbol_value(bs); + + return bfd_asymbol_name(as)[0] - bfd_asymbol_name(bs)[0]; +} + +static int bfd2elf_binding(asymbol *symbol) +{ + if (symbol->flags & BSF_WEAK) + return STB_WEAK; + if (symbol->flags & BSF_GLOBAL) + return STB_GLOBAL; + if (symbol->flags & BSF_LOCAL) + return STB_LOCAL; + return -1; +} + +int dso__load_bfd_symbols(struct dso *dso, const char *debugfile) +{ + int err = -1; + long symbols_size, symbols_count, i; + asection *section; + asymbol **symbols, *sym; + struct symbol *symbol; + bfd *abfd; + u64 start, len; + + ensure_bfd_init(); + abfd = bfd_openr(debugfile, NULL); + if (!abfd) + return -1; + + if (!bfd_check_format(abfd, bfd_object)) { + pr_debug2("%s: cannot read %s bfd file.\n", __func__, + dso__long_name(dso)); + goto out_close; + } + + if (bfd_get_flavour(abfd) == bfd_target_elf_flavour) + goto out_close; + + symbols_size = bfd_get_symtab_upper_bound(abfd); + if (symbols_size == 0) { + bfd_close(abfd); + return 0; + } + + if (symbols_size < 0) + goto out_close; + + symbols = malloc(symbols_size); + if (!symbols) + goto out_close; + + symbols_count = bfd_canonicalize_symtab(abfd, symbols); + if (symbols_count < 0) + goto out_free; + + section = bfd_get_section_by_name(abfd, ".text"); + if (section) { + for (i = 0; i < symbols_count; ++i) { + if (!strcmp(bfd_asymbol_name(symbols[i]), "__ImageBase") || + !strcmp(bfd_asymbol_name(symbols[i]), "__image_base__")) + break; + } + if (i < symbols_count) { + /* PE symbols can only have 4 bytes, so use .text high bits */ + u64 text_offset = (section->vma - (u32)section->vma) + + (u32)bfd_asymbol_value(symbols[i]); + dso__set_text_offset(dso, text_offset); + dso__set_text_end(dso, (section->vma - text_offset) + section->size); + } else { + dso__set_text_offset(dso, section->vma - section->filepos); + dso__set_text_end(dso, section->filepos + section->size); + } + } + + qsort(symbols, symbols_count, sizeof(asymbol *), bfd_symbols__cmpvalue); + +#ifdef bfd_get_section +#define bfd_asymbol_section bfd_get_section +#endif + for (i = 0; i < symbols_count; ++i) { + sym = symbols[i]; + section = bfd_asymbol_section(sym); + if (bfd2elf_binding(sym) < 0) + continue; + + while (i + 1 < symbols_count && + bfd_asymbol_section(symbols[i + 1]) == section && + bfd2elf_binding(symbols[i + 1]) < 0) + i++; + + if (i + 1 < symbols_count && + bfd_asymbol_section(symbols[i + 1]) == section) + len = symbols[i + 1]->value - sym->value; + else + len = section->size - sym->value; + + start = bfd_asymbol_value(sym) - dso__text_offset(dso); + symbol = symbol__new(start, len, bfd2elf_binding(sym), STT_FUNC, + bfd_asymbol_name(sym)); + if (!symbol) + goto out_free; + + symbols__insert(dso__symbols(dso), symbol); + } +#ifdef bfd_get_section +#undef bfd_asymbol_section +#endif + + symbols__fixup_end(dso__symbols(dso), false); + symbols__fixup_duplicate(dso__symbols(dso)); + dso__set_adjust_symbols(dso, true); + + err = 0; +out_free: + free(symbols); +out_close: + bfd_close(abfd); + return err; +} + +int libbfd__read_build_id(const char *filename, struct build_id *bid) +{ + size_t size = sizeof(bid->data); + int err = -1, fd; + bfd *abfd; + + if (!filename) + return -EFAULT; + + errno = 0; + if (!is_regular_file(filename)) + return errno == 0 ? -EWOULDBLOCK : -errno; + + fd = open(filename, O_RDONLY); + if (fd < 0) + return -1; + + ensure_bfd_init(); + abfd = bfd_fdopenr(filename, /*target=*/NULL, fd); + if (!abfd) + return -1; + + if (!bfd_check_format(abfd, bfd_object)) { + pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename); + goto out_close; + } + + if (!abfd->build_id || abfd->build_id->size > size) + goto out_close; + + memcpy(bid->data, abfd->build_id->data, abfd->build_id->size); + memset(bid->data + abfd->build_id->size, 0, size - abfd->build_id->size); + err = bid->size = abfd->build_id->size; + +out_close: + bfd_close(abfd); + return err; +} + +int libbfd_filename__read_debuglink(const char *filename, char *debuglink, + size_t size) +{ + int err = -1; + asection *section; + bfd *abfd; + + ensure_bfd_init(); + abfd = bfd_openr(filename, NULL); + if (!abfd) + return -1; + + if (!bfd_check_format(abfd, bfd_object)) { + pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename); + goto out_close; + } + + section = bfd_get_section_by_name(abfd, ".gnu_debuglink"); + if (!section) + goto out_close; + + if (section->size > size) + goto out_close; + + if (!bfd_get_section_contents(abfd, section, debuglink, 0, + section->size)) + goto out_close; + + err = 0; + +out_close: + bfd_close(abfd); + return err; +} + +int symbol__disassemble_bpf_libbfd(struct symbol *sym __maybe_unused, + struct annotate_args *args __maybe_unused) +{ +#ifdef HAVE_LIBBPF_SUPPORT + struct annotation *notes = symbol__annotation(sym); + struct bpf_prog_linfo *prog_linfo = NULL; + struct bpf_prog_info_node *info_node; + int len = sym->end - sym->start; + disassembler_ftype disassemble; + struct map *map = args->ms->map; + struct perf_bpil *info_linear; + struct disassemble_info info; + struct dso *dso = map__dso(map); + int pc = 0, count, sub_id; + struct btf *btf = NULL; + char tpath[PATH_MAX]; + size_t buf_size; + int nr_skip = 0; + char *buf = NULL; + bfd *bfdf; + int ret; + FILE *s; + + if (dso__binary_type(dso) != DSO_BINARY_TYPE__BPF_PROG_INFO) + return SYMBOL_ANNOTATE_ERRNO__BPF_INVALID_FILE; + + pr_debug("%s: handling sym %s addr %" PRIx64 " len %" PRIx64 "\n", __func__, + sym->name, sym->start, sym->end - sym->start); + + memset(tpath, 0, sizeof(tpath)); + perf_exe(tpath, sizeof(tpath)); + + ensure_bfd_init(); + bfdf = bfd_openr(tpath, NULL); + if (bfdf == NULL) + abort(); + + if (!bfd_check_format(bfdf, bfd_object)) + abort(); + + s = open_memstream(&buf, &buf_size); + if (!s) { + ret = errno; + goto out; + } + init_disassemble_info_compat(&info, s, + (fprintf_ftype) fprintf, + fprintf_styled); + info.arch = bfd_get_arch(bfdf); + info.mach = bfd_get_mach(bfdf); + + info_node = perf_env__find_bpf_prog_info(dso__bpf_prog(dso)->env, + dso__bpf_prog(dso)->id); + if (!info_node) { + ret = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF; + goto out; + } + info_linear = info_node->info_linear; + sub_id = dso__bpf_prog(dso)->sub_id; + + /* jited_prog_insns is only valid if bpil_offs_to_addr() converted it */ + if (!(info_linear->arrays & (1UL << PERF_BPIL_JITED_INSNS))) { + ret = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF; + goto out; + } + info.buffer = (void *)(uintptr_t)(info_linear->info.jited_prog_insns); + info.buffer_length = info_linear->info.jited_prog_len; + + if (info_linear->info.nr_line_info) + prog_linfo = bpf_prog_linfo__new(&info_linear->info); + + if (info_linear->info.btf_id) { + struct btf_node *node; + + node = perf_env__find_btf(dso__bpf_prog(dso)->env, + info_linear->info.btf_id); + if (node) + btf = btf__new((__u8 *)(node->data), + node->data_size); + } + + disassemble_init_for_target(&info); + +#ifdef DISASM_FOUR_ARGS_SIGNATURE + disassemble = disassembler(info.arch, + bfd_big_endian(bfdf), + info.mach, + bfdf); +#else + disassemble = disassembler(bfdf); +#endif + if (disassemble == NULL) + abort(); + + /* jited_ksyms is only valid if bpil_offs_to_addr() converted it */ + if (!(info_linear->arrays & (1UL << PERF_BPIL_JITED_KSYMS))) { + ret = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF; + goto out; + } + + fflush(s); + do { + const struct bpf_line_info *linfo = NULL; + struct disasm_line *dl; + size_t prev_buf_size; + const char *srcline; + u64 addr; + + addr = pc + ((u64 *)(uintptr_t)(info_linear->info.jited_ksyms))[sub_id]; + count = disassemble(pc, &info); + + if (prog_linfo) + linfo = bpf_prog_linfo__lfind_addr_func(prog_linfo, + addr, sub_id, + nr_skip); + + if (linfo && btf) { + srcline = btf__name_by_offset(btf, linfo->line_off); + nr_skip++; + } else + srcline = NULL; + + fprintf(s, "\n"); + prev_buf_size = buf_size; + fflush(s); + + if (!annotate_opts.hide_src_code && srcline) { + args->offset = -1; + args->line = (char *)srcline; + args->line_nr = 0; + args->fileloc = NULL; + args->ms->sym = sym; + dl = disasm_line__new(args); + if (dl) { + annotation_line__add(&dl->al, + ¬es->src->source); + } + } + + args->offset = pc; + args->line = buf + prev_buf_size; + args->line_nr = 0; + args->fileloc = NULL; + args->ms->sym = sym; + dl = disasm_line__new(args); + if (dl) + annotation_line__add(&dl->al, ¬es->src->source); + + pc += count; + } while (count > 0 && pc < len); + + ret = 0; +out: + bpf_prog_linfo__free(prog_linfo); + btf__free(btf); + if (s) { + fclose(s); + free(buf); + } + bfd_close(bfdf); + return ret; +#else + return SYMBOL_ANNOTATE_ERRNO__NO_LIBOPCODES_FOR_BPF; +#endif +} -- cgit v1.3.1