perf symbols: Save DSO loading errno to better report errors

Before, when some problem happened while trying to load the kernel
symtab, 'perf top' would show:

      ┌─Warning:───────────────────────────┐
      │The vmlinux file can't be used.     │
      │Kernel samples will not be resolved.│
      │                                    │
      │                                    │
      │Press any key...                    │
      └────────────────────────────────────┘

Now, it reports:

  # perf top --vmlinux /dev/null

      ┌─Warning:───────────────────────────────────────────┐
      │The /tmp/passwd file can't be used: Invalid ELF file│
      │Kernel samples will not be resolved.                │
      │                                                    │
      │                                                    │
      │Press any key...                                    │
      └────────────────────────────────────────────────────┘

This is possible because we now register the reason for not being able
to load the symtab in the dso->load_errno member, and provide a
dso__strerror_load() routine to format this error into a strerror like
string with a short reason for the error while loading.

That can be just forwarding the dso__strerror_load() call to
strerror_r(), or, for a separate errno range providing a custom message.

Reported-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2015-03-24 11:49:02 -03:00
parent 17e44dc46f
commit 18425f13a0
5 changed files with 96 additions and 15 deletions

View file

@ -595,10 +595,13 @@ static int decompress_kmodule(struct dso *dso, const char *name,
return -1;
fd = mkstemp(tmpbuf);
if (fd < 0)
if (fd < 0) {
dso->load_errno = errno;
goto out;
}
if (!decompress_to_file(m.ext, name, fd)) {
dso->load_errno = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
close(fd);
fd = -1;
}
@ -635,37 +638,49 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
Elf *elf;
int fd;
if (dso__needs_decompress(dso))
if (dso__needs_decompress(dso)) {
fd = decompress_kmodule(dso, name, type);
else
if (fd < 0)
return -1;
} else {
fd = open(name, O_RDONLY);
if (fd < 0)
return -1;
if (fd < 0) {
dso->load_errno = errno;
return -1;
}
}
elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
if (elf == NULL) {
pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
goto out_close;
}
if (gelf_getehdr(elf, &ehdr) == NULL) {
dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
pr_debug("%s: cannot get elf header.\n", __func__);
goto out_elf_end;
}
if (dso__swap_init(dso, ehdr.e_ident[EI_DATA]))
if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
goto out_elf_end;
}
/* Always reject images with a mismatched build-id: */
if (dso->has_build_id) {
u8 build_id[BUILD_ID_SIZE];
if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0)
if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
goto out_elf_end;
}
if (!dso__build_id_equal(dso, build_id))
if (!dso__build_id_equal(dso, build_id)) {
dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
goto out_elf_end;
}
}
ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
@ -701,8 +716,10 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
}
ss->name = strdup(name);
if (!ss->name)
if (!ss->name) {
dso->load_errno = errno;
goto out_elf_end;
}
ss->elf = elf;
ss->fd = fd;