Messages in this thread Patch in this message | | | From | Wang Nan <> | Subject | [PATCH v2] perf: report/annotate: fix segfault problem. | Date | Fri, 3 Apr 2015 05:56:25 +0000 |
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perf report and perf annotate are easy to trigger segfault if trace data contain kernel module information like this:
# perf report -D -i ./perf.data ... 0 0 0x188 [0x50]: PERF_RECORD_MMAP -1/0: [0xffffffbff1018000(0xf068000) @ 0]: x [test_module] ...
# perf report -i ./perf.data --objdump=/path/to/objdump --kallsyms=/path/to/kallsyms
perf: Segmentation fault -------- backtrace -------- /path/to/perf[0x503478] /lib64/libc.so.6(+0x3545f)[0x7fb201f3745f] /path/to/perf[0x499b56] /path/to/perf(dso__load_kallsyms+0x13c)[0x49b56c] /path/to/perf(dso__load+0x72e)[0x49c21e] /path/to/perf(map__load+0x6e)[0x4ae9ee] /path/to/perf(thread__find_addr_map+0x24c)[0x47deec] /path/to/perf(perf_event__preprocess_sample+0x88)[0x47e238] /path/to/perf[0x43ad02] /path/to/perf[0x4b55bc] /path/to/perf(ordered_events__flush+0xca)[0x4b57ea] /path/to/perf[0x4b1a01] /path/to/perf(perf_session__process_events+0x3be)[0x4b428e] /path/to/perf(cmd_report+0xf11)[0x43bfc1] /path/to/perf[0x474702] /path/to/perf(main+0x5f5)[0x42de95] /lib64/libc.so.6(__libc_start_main+0xf4)[0x7fb201f23bd4] /path/to/perf[0x42dfc4]
This is because __kmod_path__parse regard '[' leading name as kernel instead of kernel module. The DSO will then be passed to dso__load_kernel_sym() then dso__load_kcore() because of --kallsyms argument. The segfault is triggered because the kmap structure is not initialized.
Although in --vmlinux case such segfault can be avoided, the symbols in the kernel module are unable to be retrived since the attribute of DSO is incorrect.
This patch fixes __kmod_path__parse, make it regard names like '[test_module]' as kernel module.
Signed-off-by: Wang Nan <wangnan0@huawei.com> ---
Patch v1 doesn't consider module named as [aaa.bbb].
--- tools/perf/util/dso.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c index fc0ddd5..08d7aaf 100644 --- a/tools/perf/util/dso.c +++ b/tools/perf/util/dso.c @@ -214,12 +214,23 @@ int __kmod_path__parse(struct kmod_path *m, const char *path, { const char *name = strrchr(path, '/'); const char *ext = strrchr(path, '.'); + bool is_simple_name = false; memset(m, 0x0, sizeof(*m)); name = name ? name + 1 : path; + /* + * '.' is also a valid character. For example: [aaa.bbb] is a + * valid module name. '[' should have higher priority than + * '.ko' suffix. + */ + if ((name[0] == '[') && (strncmp(name, "[vdso]", 6) != 0)) { + m->kmod = true; + is_simple_name = true; + } + /* No extension, just return name. */ - if (ext == NULL) { + if ((ext == NULL) || is_simple_name) { if (alloc_name) { m->name = strdup(name); return m->name ? 0 : -ENOMEM; -- 1.8.3.4
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