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:
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17e44dc46f
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18425f13a0
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@ -757,8 +757,10 @@ static void perf_event__process_sample(struct perf_tool *tool,
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al.map == machine->vmlinux_maps[MAP__FUNCTION] &&
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RB_EMPTY_ROOT(&al.map->dso->symbols[MAP__FUNCTION])) {
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if (symbol_conf.vmlinux_name) {
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ui__warning("The %s file can't be used.\n%s",
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symbol_conf.vmlinux_name, msg);
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char serr[256];
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dso__strerror_load(al.map->dso, serr, sizeof(serr));
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ui__warning("The %s file can't be used: %s\n%s",
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symbol_conf.vmlinux_name, serr, msg);
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} else {
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ui__warning("A vmlinux file was not found.\n%s",
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msg);
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@ -1137,3 +1137,36 @@ enum dso_type dso__type(struct dso *dso, struct machine *machine)
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return dso__type_fd(fd);
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}
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int dso__strerror_load(struct dso *dso, char *buf, size_t buflen)
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{
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int idx, errnum = dso->load_errno;
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/*
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* This must have a same ordering as the enum dso_load_errno.
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*/
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static const char *dso_load__error_str[] = {
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"Internal tools/perf/ library error",
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"Invalid ELF file",
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"Can not read build id",
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"Mismatching build id",
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"Decompression failure",
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};
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BUG_ON(buflen == 0);
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if (errnum >= 0) {
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const char *err = strerror_r(errnum, buf, buflen);
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if (err != buf)
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scnprintf(buf, buflen, "%s", err);
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return 0;
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}
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if (errnum < __DSO_LOAD_ERRNO__START || errnum >= __DSO_LOAD_ERRNO__END)
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return -1;
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idx = errnum - __DSO_LOAD_ERRNO__START;
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scnprintf(buf, buflen, "%s", dso_load__error_str[idx]);
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return 0;
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}
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@ -60,6 +60,31 @@ enum dso_type {
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DSO__TYPE_X32BIT,
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};
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enum dso_load_errno {
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DSO_LOAD_ERRNO__SUCCESS = 0,
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/*
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* Choose an arbitrary negative big number not to clash with standard
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* errno since SUS requires the errno has distinct positive values.
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* See 'Issue 6' in the link below.
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*
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* http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/errno.h.html
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*/
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__DSO_LOAD_ERRNO__START = -10000,
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DSO_LOAD_ERRNO__INTERNAL_ERROR = __DSO_LOAD_ERRNO__START,
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/* for symsrc__init() */
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DSO_LOAD_ERRNO__INVALID_ELF,
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DSO_LOAD_ERRNO__CANNOT_READ_BUILDID,
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DSO_LOAD_ERRNO__MISMATCHING_BUILDID,
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/* for decompress_kmodule */
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DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE,
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__DSO_LOAD_ERRNO__END,
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};
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#define DSO__SWAP(dso, type, val) \
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({ \
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type ____r = val; \
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@ -113,6 +138,7 @@ struct dso {
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enum dso_swap_type needs_swap;
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enum dso_binary_type symtab_type;
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enum dso_binary_type binary_type;
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enum dso_load_errno load_errno;
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u8 adjust_symbols:1;
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u8 has_build_id:1;
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u8 has_srcline:1;
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@ -294,4 +320,6 @@ void dso__free_a2l(struct dso *dso);
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enum dso_type dso__type(struct dso *dso, struct machine *machine);
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int dso__strerror_load(struct dso *dso, char *buf, size_t buflen);
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#endif /* __PERF_DSO */
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@ -595,10 +595,13 @@ static int decompress_kmodule(struct dso *dso, const char *name,
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return -1;
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fd = mkstemp(tmpbuf);
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if (fd < 0)
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if (fd < 0) {
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dso->load_errno = errno;
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goto out;
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}
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if (!decompress_to_file(m.ext, name, fd)) {
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dso->load_errno = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
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close(fd);
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fd = -1;
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}
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@ -635,37 +638,49 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
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Elf *elf;
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int fd;
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if (dso__needs_decompress(dso))
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if (dso__needs_decompress(dso)) {
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fd = decompress_kmodule(dso, name, type);
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else
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if (fd < 0)
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return -1;
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} else {
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fd = open(name, O_RDONLY);
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if (fd < 0)
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return -1;
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if (fd < 0) {
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dso->load_errno = errno;
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return -1;
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}
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}
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elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
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if (elf == NULL) {
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pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
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dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
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goto out_close;
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}
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if (gelf_getehdr(elf, &ehdr) == NULL) {
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dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
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pr_debug("%s: cannot get elf header.\n", __func__);
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goto out_elf_end;
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}
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if (dso__swap_init(dso, ehdr.e_ident[EI_DATA]))
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if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
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dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
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goto out_elf_end;
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}
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/* Always reject images with a mismatched build-id: */
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if (dso->has_build_id) {
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u8 build_id[BUILD_ID_SIZE];
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if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0)
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if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
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dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
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goto out_elf_end;
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}
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if (!dso__build_id_equal(dso, build_id))
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if (!dso__build_id_equal(dso, build_id)) {
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dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
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goto out_elf_end;
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}
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}
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ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
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@ -701,8 +716,10 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
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}
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ss->name = strdup(name);
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if (!ss->name)
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if (!ss->name) {
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dso->load_errno = errno;
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goto out_elf_end;
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}
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ss->elf = elf;
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ss->fd = fd;
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@ -246,13 +246,12 @@ out:
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return ret;
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}
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int symsrc__init(struct symsrc *ss, struct dso *dso __maybe_unused,
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const char *name,
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int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
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enum dso_binary_type type)
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{
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int fd = open(name, O_RDONLY);
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if (fd < 0)
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return -1;
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goto out_errno;
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ss->name = strdup(name);
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if (!ss->name)
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return 0;
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out_close:
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close(fd);
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out_errno:
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dso->load_errno = errno;
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return -1;
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}
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