From 1f121b03d058dd07199d8924373d3c52a207f63b Mon Sep 17 00:00:00 2001
From: Wang Nan <wangnan0@huawei.com>
Date: Wed, 3 Jun 2015 08:52:21 +0000
Subject: perf tools: Deal with kernel module names in '[]' correctly
Before patch ba92732e9808 ('perf kmaps: Check kmaps to make code more
robust'), 'perf report' and 'perf annotate' will segfault if trace data
contains 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 treats '[' leading names as kernel
name instead of names of kernel module.
If perf.data contains build information and the buildid of such modules
can be found, the dso->kernel of it will be set to DSO_TYPE_KERNEL by
__event_process_build_id(), not kernel module.
It will then be passed to dso__load() -> dso__load_kernel_sym() ->
dso__load_kcore() if --kallsyms is provided.
The refered patch adds NULL pointer checker to avoid segfault. However,
such kernel modules are still processed incorrectly.
This patch fixes __kmod_path__parse, makes it treat names like
'[test_module]' as kernel modules.
kmod-path.c is also update to reflect the above changes.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/r/1433321541-170245-1-git-send-email-wangnan0@huawei.com
[ Fixed the merged with 0443f36b0de0 ("perf machine: Fix the search
for the kernel DSO on the unified list" ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/dso.c | 47 ++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 42 insertions(+), 5 deletions(-)
(limited to 'tools/perf/util/dso.c')
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index b335db3532a2..5ec9e892c89b 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -166,12 +166,28 @@ bool is_supported_compression(const char *ext)
return false;
}
-bool is_kernel_module(const char *pathname)
+bool is_kernel_module(const char *pathname, int cpumode)
{
struct kmod_path m;
-
- if (kmod_path__parse(&m, pathname))
- return NULL;
+ int mode = cpumode & PERF_RECORD_MISC_CPUMODE_MASK;
+
+ WARN_ONCE(mode != cpumode,
+ "Internal error: passing unmasked cpumode (%x) to is_kernel_module",
+ cpumode);
+
+ switch (mode) {
+ case PERF_RECORD_MISC_USER:
+ case PERF_RECORD_MISC_HYPERVISOR:
+ case PERF_RECORD_MISC_GUEST_USER:
+ return false;
+ /* Treat PERF_RECORD_MISC_CPUMODE_UNKNOWN as kernel */
+ default:
+ if (kmod_path__parse(&m, pathname)) {
+ pr_err("Failed to check whether %s is a kernel module or not. Assume it is.",
+ pathname);
+ return true;
+ }
+ }
return m.kmod;
}
@@ -215,12 +231,33 @@ 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 module name. For example:
+ * [aaa.bbb] is a valid module name. '[' should have higher
+ * priority than '.ko' suffix.
+ *
+ * The kernel names are from machine__mmap_name. Such
+ * name should belong to kernel itself, not kernel module.
+ */
+ if (name[0] == '[') {
+ is_simple_name = true;
+ if ((strncmp(name, "[kernel.kallsyms]", 17) == 0) ||
+ (strncmp(name, "[guest.kernel.kallsyms", 22) == 0) ||
+ (strncmp(name, "[vdso]", 6) == 0) ||
+ (strncmp(name, "[vsyscall]", 10) == 0)) {
+ m->kmod = false;
+
+ } else
+ m->kmod = 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;
--
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