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>
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 78ffde9..476268c 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -595,10 +595,13 @@
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 @@
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 @@
}
ss->name = strdup(name);
- if (!ss->name)
+ if (!ss->name) {
+ dso->load_errno = errno;
goto out_elf_end;
+ }
ss->elf = elf;
ss->fd = fd;