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Date:   Tue, 24 Oct 2023 15:23:07 -0700
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Subject: [PATCH v3 04/50] libperf rc_check: Add RC_CHK_EQUAL
From:   Ian Rogers <irogers@google.com>
To:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Nick Terrell <terrelln@fb.com>,
        Kan Liang <kan.liang@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>, Leo Yan <leo.yan@linaro.org>,
        Song Liu <song@kernel.org>,
        Sandipan Das <sandipan.das@amd.com>,
        James Clark <james.clark@arm.com>,
        Anshuman Khandual <anshuman.khandual@arm.com>,
        Miguel Ojeda <ojeda@kernel.org>,
        Liam Howlett <liam.howlett@oracle.com>,
        Yang Jihong <yangjihong1@huawei.com>,
        Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
        Kajol Jain <kjain@linux.ibm.com>,
        K Prateek Nayak <kprateek.nayak@amd.com>,
        Sean Christopherson <seanjc@google.com>,
        Yanteng Si <siyanteng@loongson.cn>,
        Ravi Bangoria <ravi.bangoria@amd.com>,
        German Gomez <german.gomez@arm.com>,
        Changbin Du <changbin.du@huawei.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        liuwenyu <liuwenyu7@huawei.com>, linux-kernel@vger.kernel.org,
        linux-perf-users@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Comparing pointers with reference count checking is tricky to avoid a
SEGV. Add a convenience macro to simplify and use.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/lib/perf/include/internal/rc_check.h | 7 +++++++
 tools/perf/builtin-sched.c                 | 2 +-
 tools/perf/tests/hists_link.c              | 4 ++--
 tools/perf/tests/thread-maps-share.c       | 9 ++++-----
 tools/perf/util/callchain.c                | 2 +-
 tools/perf/util/hist.c                     | 2 +-
 tools/perf/util/machine.c                  | 4 ++--
 tools/perf/util/sort.c                     | 2 +-
 tools/perf/util/symbol.c                   | 4 ++--
 9 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/tools/lib/perf/include/internal/rc_check.h b/tools/lib/perf/include/internal/rc_check.h
index e88a6d8a0b0f..f80ddfc80129 100644
--- a/tools/lib/perf/include/internal/rc_check.h
+++ b/tools/lib/perf/include/internal/rc_check.h
@@ -54,6 +54,9 @@
 /* A put operation removing the indirection layer. */
 #define RC_CHK_PUT(object) {}
 
+/* Pointer equality when the indirection may or may not be there. */
+#define RC_CHK_EQUAL(object1, object2) (object1 == object2)
+
 #else
 
 /* Replaces "struct foo" so that the pointer may be interposed. */
@@ -101,6 +104,10 @@
 		}				\
 	} while(0)
 
+/* Pointer equality when the indirection may or may not be there. */
+#define RC_CHK_EQUAL(object1, object2) (object1 == object2 || \
+		(object1 && object2 && object1->orig == object2->orig))
+
 #endif
 
 #endif /* __LIBPERF_INTERNAL_RC_CHECK_H */
diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 9ab300b6f131..dd6065afbbaf 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -1385,7 +1385,7 @@ static int pid_cmp(struct work_atoms *l, struct work_atoms *r)
 {
 	pid_t l_tid, r_tid;
 
-	if (RC_CHK_ACCESS(l->thread) == RC_CHK_ACCESS(r->thread))
+	if (RC_CHK_EQUAL(l->thread, r->thread))
 		return 0;
 	l_tid = thread__tid(l->thread);
 	r_tid = thread__tid(r->thread);
diff --git a/tools/perf/tests/hists_link.c b/tools/perf/tests/hists_link.c
index 2d19657ab5e0..5b6f1e883466 100644
--- a/tools/perf/tests/hists_link.c
+++ b/tools/perf/tests/hists_link.c
@@ -148,8 +148,8 @@ static int find_sample(struct sample *samples, size_t nr_samples,
 		       struct thread *t, struct map *m, struct symbol *s)
 {
 	while (nr_samples--) {
-		if (RC_CHK_ACCESS(samples->thread) == RC_CHK_ACCESS(t) &&
-		    RC_CHK_ACCESS(samples->map) == RC_CHK_ACCESS(m) &&
+		if (RC_CHK_EQUAL(samples->thread, t) &&
+		    RC_CHK_EQUAL(samples->map, m) &&
 		    samples->sym == s)
 			return 1;
 		samples++;
diff --git a/tools/perf/tests/thread-maps-share.c b/tools/perf/tests/thread-maps-share.c
index faf980b26252..7fa6f7c568e2 100644
--- a/tools/perf/tests/thread-maps-share.c
+++ b/tools/perf/tests/thread-maps-share.c
@@ -46,9 +46,9 @@ static int test__thread_maps_share(struct test_suite *test __maybe_unused, int s
 	TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(maps)), 4);
 
 	/* test the maps pointer is shared */
-	TEST_ASSERT_VAL("maps don't match", RC_CHK_ACCESS(maps) == RC_CHK_ACCESS(thread__maps(t1)));
-	TEST_ASSERT_VAL("maps don't match", RC_CHK_ACCESS(maps) == RC_CHK_ACCESS(thread__maps(t2)));
-	TEST_ASSERT_VAL("maps don't match", RC_CHK_ACCESS(maps) == RC_CHK_ACCESS(thread__maps(t3)));
+	TEST_ASSERT_VAL("maps don't match", RC_CHK_EQUAL(maps, thread__maps(t1)));
+	TEST_ASSERT_VAL("maps don't match", RC_CHK_EQUAL(maps, thread__maps(t2)));
+	TEST_ASSERT_VAL("maps don't match", RC_CHK_EQUAL(maps, thread__maps(t3)));
 
 	/*
 	 * Verify the other leader was created by previous call.
@@ -73,8 +73,7 @@ static int test__thread_maps_share(struct test_suite *test __maybe_unused, int s
 	other_maps = thread__maps(other);
 	TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(other_maps)), 2);
 
-	TEST_ASSERT_VAL("maps don't match", RC_CHK_ACCESS(other_maps) ==
-					    RC_CHK_ACCESS(thread__maps(other_leader)));
+	TEST_ASSERT_VAL("maps don't match", RC_CHK_EQUAL(other_maps, thread__maps(other_leader)));
 
 	/* release thread group */
 	thread__put(t3);
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index aee937d14fbb..18d545c0629e 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -1142,7 +1142,7 @@ int fill_callchain_info(struct addr_location *al, struct callchain_cursor_node *
 		if (al->map == NULL)
 			goto out;
 	}
-	if (RC_CHK_ACCESS(al->maps) == RC_CHK_ACCESS(machine__kernel_maps(machine))) {
+	if (RC_CHK_EQUAL(al->maps, machine__kernel_maps(machine))) {
 		if (machine__is_host(machine)) {
 			al->cpumode = PERF_RECORD_MISC_KERNEL;
 			al->level = 'k';
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index 3dc8a4968beb..cde0078e6c90 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -2142,7 +2142,7 @@ static bool hists__filter_entry_by_thread(struct hists *hists,
 					  struct hist_entry *he)
 {
 	if (hists->thread_filter != NULL &&
-	    RC_CHK_ACCESS(he->thread) != RC_CHK_ACCESS(hists->thread_filter)) {
+	    !RC_CHK_EQUAL(he->thread, hists->thread_filter)) {
 		he->filtered |= (1 << HIST_FILTER__THREAD);
 		return true;
 	}
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index e0e2c4a943e4..098600d983c5 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -969,7 +969,7 @@ static int machine__process_ksymbol_unregister(struct machine *machine,
 	if (!map)
 		return 0;
 
-	if (RC_CHK_ACCESS(map) != RC_CHK_ACCESS(machine->vmlinux_map))
+	if (!RC_CHK_EQUAL(map, machine->vmlinux_map))
 		maps__remove(machine__kernel_maps(machine), map);
 	else {
 		struct dso *dso = map__dso(map);
@@ -2058,7 +2058,7 @@ static void __machine__remove_thread(struct machine *machine, struct thread_rb_n
 	if (!nd)
 		nd = thread_rb_node__find(th, &threads->entries.rb_root);
 
-	if (threads->last_match && RC_CHK_ACCESS(threads->last_match) == RC_CHK_ACCESS(th))
+	if (threads->last_match && RC_CHK_EQUAL(threads->last_match, th))
 		threads__set_last_match(threads, NULL);
 
 	if (lock)
diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index 6aa1c7f2b444..80e4f6132740 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -128,7 +128,7 @@ static int hist_entry__thread_filter(struct hist_entry *he, int type, const void
 	if (type != HIST_FILTER__THREAD)
 		return -1;
 
-	return th && RC_CHK_ACCESS(he->thread) != RC_CHK_ACCESS(th);
+	return th && !RC_CHK_EQUAL(he->thread, th);
 }
 
 struct sort_entry sort_thread = {
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 96587fd7a5a2..822f4dcebfe6 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -877,7 +877,7 @@ static int maps__split_kallsyms(struct maps *kmaps, struct dso *dso, u64 delta,
 			*module++ = '\0';
 			curr_map_dso = map__dso(curr_map);
 			if (strcmp(curr_map_dso->short_name, module)) {
-				if (RC_CHK_ACCESS(curr_map) != RC_CHK_ACCESS(initial_map) &&
+				if (!RC_CHK_EQUAL(curr_map, initial_map) &&
 				    dso->kernel == DSO_SPACE__KERNEL_GUEST &&
 				    machine__is_default_guest(machine)) {
 					/*
@@ -1469,7 +1469,7 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
 
 		list_del_init(&new_node->node);
 
-		if (RC_CHK_ACCESS(new_map) == RC_CHK_ACCESS(replacement_map)) {
+		if (RC_CHK_EQUAL(new_map, replacement_map)) {
 			struct map *map_ref;
 
 			map__set_start(map, map__start(new_map));
-- 
2.42.0.758.gaed0368e0e-goog