[PATCH V3 1/2] perf tools: Make it possible to see perf's kernel and module memory mappings
From: Adrian Hunter
Date: Thu Feb 08 2024 - 03:56:45 EST
Dump kmaps if using 'perf --debug kmaps' or verbose > 2 (e.g. -vvv) for
tools 'perf script' and 'perf report' if there is no browser.
Example:
$ perf --debug kmaps script 2>&1 >/dev/null | grep kvm.intel
build id event received for /lib/modules/6.7.2-local/kernel/arch/x86/kvm/kvm-intel.ko: 0691d75e10e72ebbbd45a44c59f6d00a5604badf [20]
Map: 0-3a3 4f5d8 [kvm_intel].modinfo
Map: 0-5240 5f280 [kvm_intel]__versions
Map: 0-30 64 [kvm_intel].note.Linux
Map: 0-14 644c0 [kvm_intel].orc_header
Map: 0-5297 43680 [kvm_intel].rodata
Map: 0-5bee 3b837 [kvm_intel].text.unlikely
Map: 0-7e0 41430 [kvm_intel].noinstr.text
Map: 0-2080 713c0 [kvm_intel].bss
Map: 0-26 705c8 [kvm_intel].data..read_mostly
Map: 0-5888 6a4c0 [kvm_intel].data
Map: 0-22 70220 [kvm_intel].data.once
Map: 0-40 705f0 [kvm_intel].data..percpu
Map: 0-1685 41d20 [kvm_intel].init.text
Map: 0-4b8 6fd60 [kvm_intel].init.data
Map: 0-380 70248 [kvm_intel]__dyndbg
Map: 0-8 70218 [kvm_intel].exit.data
Map: 0-438 4f980 [kvm_intel]__param
Map: 0-5f5 4ca0f [kvm_intel].rodata.str1.1
Map: 0-3657 493b8 [kvm_intel].rodata.str1.8
Map: 0-e0 70640 [kvm_intel].data..ro_after_init
Map: 0-500 70ec0 [kvm_intel].gnu.linkonce.this_module
Map: ffffffffc13a7000-ffffffffc1421000 a0 /lib/modules/6.7.2-local/kernel/arch/x86/kvm/kvm-intel.ko
The example above shows how the module section mappings are all wrong
except for the main .text mapping at 0xffffffffc13a7000.
Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
Changes in V3:
- re-base
Changes in V2:
- add dump to perf report (if no browser) as well as perf script
- add 'perf --debug kmaps' option also to dump kmaps
tools/perf/Documentation/perf.txt | 2 ++
tools/perf/builtin-report.c | 2 ++
tools/perf/builtin-script.c | 3 +++
tools/perf/util/debug.c | 3 +++
tools/perf/util/debug.h | 1 +
tools/perf/util/python.c | 1 +
tools/perf/util/session.c | 11 +++++++++++
tools/perf/util/session.h | 2 ++
8 files changed, 25 insertions(+)
diff --git a/tools/perf/Documentation/perf.txt b/tools/perf/Documentation/perf.txt
index a7cf7bc2f968..09f516f3fdfb 100644
--- a/tools/perf/Documentation/perf.txt
+++ b/tools/perf/Documentation/perf.txt
@@ -63,6 +63,8 @@ OPTIONS
in browser mode
perf-event-open - Print perf_event_open() arguments and
return value
+ kmaps - Print kernel and module maps (perf script
+ and perf report without browser)
--debug-file::
Write debug output to a specified file.
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index ccb91fe6b876..8e16fa261e6f 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -1766,6 +1766,8 @@ int cmd_report(int argc, const char **argv)
} else
ret = 0;
+ if (!use_browser && (verbose > 2 || debug_kmaps))
+ perf_session__dump_kmaps(session);
error:
if (report.ptime_range) {
itrace_synth_opts__clear_time_range(&itrace_synth_opts);
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index af63b7c37c8a..24baa8284add 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -4378,6 +4378,9 @@ int cmd_script(int argc, const char **argv)
flush_scripting();
+ if (verbose > 2 || debug_kmaps)
+ perf_session__dump_kmaps(session);
+
out_delete:
if (script.ptime_range) {
itrace_synth_opts__clear_time_range(&itrace_synth_opts);
diff --git a/tools/perf/util/debug.c b/tools/perf/util/debug.c
index e282b4ceb4d2..c39ee0fcb8cf 100644
--- a/tools/perf/util/debug.c
+++ b/tools/perf/util/debug.c
@@ -33,6 +33,7 @@
#endif
int verbose;
+int debug_kmaps;
int debug_peo_args;
bool dump_trace = false, quiet = false;
int debug_ordered_events;
@@ -229,6 +230,7 @@ static struct sublevel_option debug_opts[] = {
{ .name = "stderr", .value_ptr = &redirect_to_stderr},
{ .name = "data-convert", .value_ptr = &debug_data_convert },
{ .name = "perf-event-open", .value_ptr = &debug_peo_args },
+ { .name = "kmaps", .value_ptr = &debug_kmaps },
{ .name = NULL, }
};
@@ -267,6 +269,7 @@ int perf_quiet_option(void)
/* For debug variables that are used as bool types, set to 0. */
redirect_to_stderr = 0;
debug_peo_args = 0;
+ debug_kmaps = 0;
return 0;
}
diff --git a/tools/perf/util/debug.h b/tools/perf/util/debug.h
index de8870980d44..35a7a5ae762e 100644
--- a/tools/perf/util/debug.h
+++ b/tools/perf/util/debug.h
@@ -9,6 +9,7 @@
#include <linux/compiler.h>
extern int verbose;
+extern int debug_kmaps;
extern int debug_peo_args;
extern bool quiet, dump_trace;
extern int debug_ordered_events;
diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 8761f51b5c7c..075c0f79b1b9 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -181,6 +181,7 @@ int perf_bpf_filter__destroy(struct evsel *evsel __maybe_unused)
* implementing 'verbose' and 'eprintf'.
*/
int verbose;
+int debug_kmaps;
int debug_peo_args;
int eprintf(int level, int var, const char *fmt, ...);
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 199d3e8df315..06d0bd7fb459 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -2720,6 +2720,17 @@ size_t perf_session__fprintf(struct perf_session *session, FILE *fp)
return machine__fprintf(&session->machines.host, fp);
}
+void perf_session__dump_kmaps(struct perf_session *session)
+{
+ int save_verbose = verbose;
+
+ fflush(stdout);
+ fprintf(stderr, "Kernel and module maps:\n");
+ verbose = 0; /* Suppress verbose to print a summary only */
+ maps__fprintf(machine__kernel_maps(&session->machines.host), stderr);
+ verbose = save_verbose;
+}
+
struct evsel *perf_session__find_first_evtype(struct perf_session *session,
unsigned int type)
{
diff --git a/tools/perf/util/session.h b/tools/perf/util/session.h
index ee3715e8563b..5064c6ec11e7 100644
--- a/tools/perf/util/session.h
+++ b/tools/perf/util/session.h
@@ -133,6 +133,8 @@ size_t perf_session__fprintf_dsos_buildid(struct perf_session *session, FILE *fp
size_t perf_session__fprintf_nr_events(struct perf_session *session, FILE *fp,
bool skip_empty);
+void perf_session__dump_kmaps(struct perf_session *session);
+
struct evsel *perf_session__find_first_evtype(struct perf_session *session,
unsigned int type);
--
2.34.1