libbpf-tools/profile: add dso info and symbol offset to backtrace

Add additional information and change format of backtrace
- add symbol base offset, dso name, dso base offset
- symbol and dso info is included if it's available in target binary
- changed format:
INDEX ADDR [SYMBOL+OFFSET] (MODULE+OFFSET)

Print backtrace of ip if it failed to get syms.

Before:
  # profile -d
      psiginfo
      vscanf
      __snprintf_chk
      [unknown]
      [unknown]
      [unknown]
      [unknown]
      [unknown]
      sd_event_exit
      sd_event_dispatch
      sd_event_run
      [unknown]
      __libc_start_main
      [unknown]
      -                systemd-journal (204)
          1

      xas_load
      xas_find
      filemap_map_pages
      __handle_mm_fault
      handle_mm_fault
      do_page_fault
      do_translation_fault
      do_mem_abort
      do_el0_ia_bp_hardening
      el0_ia
      xas_load
      --
  failed to get syms
      -                PmLogCtl (138757)
        1

After:
  # profile -d
      #0  0xffffffc01018b7e8 __arm64_sys_clock_nanosleep+0x0
      iovisor#1  0xffffffc01009a93c el0_svc_handler+0x34
      iovisor#2  0xffffffc010084a08 el0_svc+0x8
      iovisor#3  0xffffffc01018b7e8 __arm64_sys_clock_nanosleep+0x0
      --
      iovisor#4  0x0000007fa0bffd14 clock_nanosleep+0x94 (/usr/lib/libc-2.31.so+0x9ed14)
      iovisor#5  0x0000007fa0c0530c nanosleep+0x1c (/usr/lib/libc-2.31.so+0xa430c)
      iovisor#6  0x0000007fa0c051e4 sleep+0x34 (/usr/lib/libc-2.31.so+0xa41e4)
      iovisor#7  0x000000558a5a9608 flb_loop+0x28 (/usr/bin/fluent-bit+0x52608)
      iovisor#8  0x000000558a59f1c4 flb_main+0xa84 (/usr/bin/fluent-bit+0x481c4)
      iovisor#9  0x0000007fa0b85124 __libc_start_main+0xe4 (/usr/lib/libc-2.31.so+0x24124)
      iovisor#10 0x000000558a59d828 _start+0x34 (/usr/bin/fluent-bit+0x46828)
      -                fluent-bit (1238)
          1

      #0  0xffffffc01027daa4 generic_copy_file_checks+0x334
      iovisor#1  0xffffffc0102ba634 __handle_mm_fault+0x8dc
      iovisor#2  0xffffffc0102baa20 handle_mm_fault+0x168
      iovisor#3  0xffffffc010ad23c0 do_page_fault+0x148
      iovisor#4  0xffffffc010ad27c0 do_translation_fault+0xb0
      iovisor#5  0xffffffc0100816b0 do_mem_abort+0x50
      iovisor#6  0xffffffc0100843b0 el0_da+0x1c
      iovisor#7  0xffffffc01027daa4 generic_copy_file_checks+0x334
      --
      iovisor#8  0x0000007f8dc12648 [unknown]
      iovisor#9  0x0000007f8dc0aef8 [unknown]
      iovisor#10 0x0000007f8dc1c990 [unknown]
      iovisor#11 0x0000007f8dc08b0c [unknown]
      iovisor#12 0x0000007f8dc08e48 [unknown]
      iovisor#13 0x0000007f8dc081c8 [unknown]
      -                PmLogCtl (2412)
          1

Signed-off-by: Eunseon Lee <[email protected]>

libbpf-tools/profile.c

@@ -289,6 +289,7 @@ static void print_map(struct ksyms *ksyms, struct syms_cache *syms_cache,
  bool has_collision = false;
  unsigned int missing_stacks = 0;
  struct key_ext_t counts[MAX_ENTRIES];
+ int nr_kern_elem = 0;
 
  ip = calloc(env.perf_max_stack_depth, sizeof(*ip));
  if (!ip) {
@@ -360,18 +361,29 @@ static void print_map(struct ksyms *ksyms, struct syms_cache *syms_cache,
  printf(" %lld\n", v);
  } else {
  // print default multi-line stack output
+ nr_kern_elem = 0;
+
  if (!env.user_stacks_only) {
  if (stack_id_err(k->kern_stack_id))
  printf(" [Missed Kernel Stack]\n");
  else if (k->kern_stack_id >= 0 &&
  bpf_map_lookup_elem(sfd, &k->kern_stack_id, ip) == 0) {
  for (j = 0; j < env.perf_max_stack_depth && ip[j]; j++) {
  ksym = ksyms__map_addr(ksyms, ip[j]);
- printf(" %s\n", ksym ? ksym->name : "[unknown]");
+ if (ksym)
+ printf(" #%-2d 0x%lx %s+0x%lx\n", j, ip[j], ksym->name, ip[j] - ksym->addr);
+ else
+ printf(" #%-2d 0x%lx [unknown]\n", j, ip[j]);
  }
+ nr_kern_elem = j;
+
  if (k->kernel_ip) {
  ksym = ksyms__map_addr(ksyms, k->kernel_ip);
- printf(" %s\n", ksym ? ksym->name : "[unknown]");
+ if (ksym)
+ printf(" #%-2d 0x%llx %s+0x%llx\n", j, k->kernel_ip, ksym->name, k->kernel_ip - ksym->addr);
+ else
+ printf(" #%-2d 0x%llx [unknown]\n", j, k->kernel_ip);
+ nr_kern_elem++;
  }
  }
  }
@@ -386,11 +398,20 @@ static void print_map(struct ksyms *ksyms, struct syms_cache *syms_cache,
  bpf_map_lookup_elem(sfd, &k->user_stack_id, ip) == 0) {
  syms = syms_cache__get_syms(syms_cache, k->pid);
  if (!syms) {
- fprintf(stderr, "failed to get syms\n");
+ for (j = 0; j < env.perf_max_stack_depth && ip[j]; j++)
+ printf(" #%-2d 0x%016lx [unknown]\n", j + nr_kern_elem, ip[j]);
  } else {
  for (j = 0; j < env.perf_max_stack_depth && ip[j]; j++) {
- sym = syms__map_addr(syms, ip[j]);
- printf(" %s\n", sym ? sym->name : "[unknown]");
+ char *dso_name;
+ uint64_t dso_offset;
+ sym = syms__map_addr_dso(syms, ip[j], &dso_name, &dso_offset);
+
+ printf(" #%-2d 0x%016lx", j + nr_kern_elem, ip[j]);
+ if (sym)
+ printf(" %s+0x%lx", sym->name, sym->offset);
+ if (dso_name)
+ printf(" (%s+0x%lx)", dso_name, dso_offset);
+ printf("\n");
  }
  }
  }

libbpf-tools/trace_helpers.c

@@ -422,6 +422,7 @@ static int dso__add_sym(struct dso *dso, const char *name, uint64_t start,
  sym->name = (void*)(unsigned long)off;
  sym->start = start;
  sym->size = size;
+ sym->offset = 0;
 
  return 0;
 }
@@ -634,8 +635,10 @@ static struct sym *dso__find_sym(struct dso *dso, uint64_t offset)
  end = mid - 1;
  }
 
- if (start == end && dso->syms[start].start <= offset)
+ if (start == end && dso->syms[start].start <= offset) {
+ (dso->syms[start]).offset = offset - dso->syms[start].start;
  return &dso->syms[start];
+ }
  return NULL;
 }
 
@@ -720,6 +723,22 @@ const struct sym *syms__map_addr(const struct syms *syms, unsigned long addr)
  return dso__find_sym(dso, offset);
 }
 
+const struct sym *syms__map_addr_dso(const struct syms *syms, unsigned long addr,
+ char **dso_name, uint64_t *dso_offset)
+{
+ struct dso *dso;
+ uint64_t offset;
+
+ dso = syms__find_dso(syms, addr, &offset);
+ if (!dso)
+ return NULL;
+
+ *dso_name = dso->name;
+ *dso_offset = offset;
+
+ return dso__find_sym(dso, offset);
+}
+
 struct syms_cache {
  struct {
  struct syms *syms;

libbpf-tools/trace_helpers.h

@@ -24,6 +24,7 @@ struct sym {
  const char *name;
  unsigned long start;
  unsigned long size;
+ unsigned long offset;
 };
 
 struct syms;
@@ -32,6 +33,8 @@ struct syms *syms__load_pid(int tgid);
 struct syms *syms__load_file(const char *fname);
 void syms__free(struct syms *syms);
 const struct sym *syms__map_addr(const struct syms *syms, unsigned long addr);
+const struct sym *syms__map_addr_dso(const struct syms *syms, unsigned long addr,
+ char **dso_name, uint64_t *dso_offset);
 
 struct syms_cache;