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perf symbol-elf: Decode dynsym even if symtab exists 

In Fedora34, libc-2.33.so has both .dynsym and .symtab sections and
most of (not all) symbols moved to .dynsym. In this case, perf only
decode the symbols in .symtab, and perf probe can not list up the
functions in the library.

To fix this issue, decode both .symtab and .dynsym sections.

Without this fix,
  -----
  $ ./perf probe -x /usr/lib64/libc-2.33.so -F
  @plt
  @plt
  calloc@plt
  free@plt
  malloc@plt
  memalign@plt
  realloc@plt
  -----

With this fix.

  -----
  $ ./perf probe -x /usr/lib64/libc-2.33.so -F
  @plt
  @plt
  a64l
  abort
  abs
  accept
  accept4
  access
  acct
  addmntent
  -----

Reported-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Stefan Liebler <stli@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Link: http://lore.kernel.org/lkml/162532652681.393143.10163733179955267999.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Masami Hiramatsu 2021-07-04 00:35:27 +09:00 committed by Arnaldo Carvalho de Melo
parent eb4717f733
commit 87704345cc
1 changed files with 54 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

82
tools/perf/util/symbol-elf.c
View File

@ -1074,8 +1074,9 @@ static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
return 0;
}
int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
struct symsrc *runtime_ss, int kmodule)
static int
dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
struct symsrc *runtime_ss, int kmodule, int dynsym)
{
struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
@ -1098,34 +1099,15 @@ int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
if (kmap && !kmaps)
return -1;
dso->symtab_type = syms_ss->type;
dso->is_64_bit = syms_ss->is_64_bit;
dso->rel = syms_ss->ehdr.e_type == ET_REL;
/*
* Modules may already have symbols from kallsyms, but those symbols
* have the wrong values for the dso maps, so remove them.
*/
if (kmodule && syms_ss->symtab)
symbols__delete(&dso->symbols);
if (!syms_ss->symtab) {
/*
* If the vmlinux is stripped, fail so we will fall back
* to using kallsyms. The vmlinux runtime symbols aren't
* of much use.
*/
if (dso->kernel)
goto out_elf_end;
syms_ss->symtab = syms_ss->dynsym;
syms_ss->symshdr = syms_ss->dynshdr;
}
elf = syms_ss->elf;
ehdr = syms_ss->ehdr;
sec = syms_ss->symtab;
shdr = syms_ss->symshdr;
if (dynsym) {
sec = syms_ss->dynsym;
shdr = syms_ss->dynshdr;
} else {
sec = syms_ss->symtab;
shdr = syms_ss->symshdr;
}
if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
".text", NULL))
@ -1312,6 +1294,50 @@ int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
return err;
}
int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
struct symsrc *runtime_ss, int kmodule)
{
int nr = 0;
int err = -1;
dso->symtab_type = syms_ss->type;
dso->is_64_bit = syms_ss->is_64_bit;
dso->rel = syms_ss->ehdr.e_type == ET_REL;
/*
* Modules may already have symbols from kallsyms, but those symbols
* have the wrong values for the dso maps, so remove them.
*/
if (kmodule && syms_ss->symtab)
symbols__delete(&dso->symbols);
if (!syms_ss->symtab) {
/*
* If the vmlinux is stripped, fail so we will fall back
* to using kallsyms. The vmlinux runtime symbols aren't
* of much use.
*/
if (dso->kernel)
return err;
} else {
err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
kmodule, 0);
if (err < 0)
return err;
nr = err;
}
if (syms_ss->dynsym) {
err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
kmodule, 1);
if (err < 0)
return err;
err += nr;
}
return err;
}
static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
{
GElf_Phdr phdr;