libbpf-tools/profile: Add module 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
      #1  0xffffffc01018b7e8 __arm64_sys_clock_nanosleep+0x0
      iovisor#2  0xffffffc01009a93c el0_svc_handler+0x34
      iovisor#3  0xffffffc010084a08 el0_svc+0x8
      --
      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
      #1  0xffffffc01027daa4 generic_copy_file_checks+0x334
      iovisor#2  0xffffffc0102ba634 __handle_mm_fault+0x8dc
      iovisor#3  0xffffffc0102baa20 handle_mm_fault+0x168
      iovisor#4  0xffffffc010ad23c0 do_page_fault+0x148
      iovisor#5  0xffffffc010ad27c0 do_translation_fault+0xb0
      iovisor#6  0xffffffc0100816b0 do_mem_abort+0x50
      iovisor#7  0xffffffc0100843b0 el0_da+0x1c
      --
      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]>

Author: ekyooo

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 idx = 0;
 
 	ip = calloc(env.perf_max_stack_depth, sizeof(*ip));
 	if (!ip) {
@@ -366,18 +367,26 @@ static void print_map(struct ksyms *ksyms, struct syms_cache *syms_cache,
 			printf(" %lld\n", v);
 		} else {
 			// print default multi-line stack output
+			idx = 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) {
 					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", idx++, k->kernel_ip, ksym->name, k->kernel_ip - ksym->addr);
+						else
+							printf("    #%-2d 0x%llx [unknown]\n", idx++, k->kernel_ip);
 					}
 					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", idx++, ip[j], ksym->name, ip[j] - ksym->addr);
+						else
+							printf("    #%-2d 0x%lx [unknown]\n", idx++, ip[j]);
 					}
 				}
 			}
@@ -392,11 +401,20 @@ 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", idx++, 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", idx++, 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;