libperf rc_check: Add RC_CHK_EQUAL

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>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: James Clark <james.clark@arm.com>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: liuwenyu <liuwenyu7@huawei.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/20231024222353.3024098-5-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

diff --git a/tools/lib/perf/include/internal/rc_check.h b/tools/lib/perf/include/internal/rc_check.h
index e88a6d8a0b0f9f8b05cff1e7289995c7dc4c08c7..f80ddfc80129e80a967bef70aeb012285b5c950e 100644 (file)
--- 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 9ab300b6f131fe8a9935c7515141c368bd215f43..dd6065afbbaf6fd41084b78219a4948d8acd9379 100644 (file)
--- 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 2d19657ab5e0a2b487c73651d113ea24f63cae08..5b6f1e883466ec08e410058699f5ee86e2b41471 100644 (file)
--- 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 faf980b26252f79465392f0e7259325796f4dad8..7fa6f7c568e2f9b0721c21621fc04b92617bd94e 100644 (file)
--- 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 aee937d14fbbf10149738547b184110b1e8e831b..18d545c0629ec6a1a08bcbed37d8758396f423c1 100644 (file)
--- 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 3dc8a4968beb9c016947e0fb86c5137e88d3c37c..cde0078e6c908c94170f9d1a518a4a47bff3ea60 100644 (file)
--- 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 e0e2c4a943e437b64b60b5d3db29e5e323eef5b8..098600d983c5e9fab148083d32cd9b6ab4b5c32f 100644 (file)
--- 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 6aa1c7f2b4448b30b403b4cdcfe63b65647b0e6f..80e4f613274015deb70028c76dc9b60ea103f6e8 100644 (file)
--- 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 96587fd7a5a2e116f0653ae21ab925aeb36a4e2f..822f4dcebfe66d8f7ca6b28e3f8992d6a76d1067 100644 (file)
--- 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));