perf callchain: Use pthread keys for tls callchain_cursor

Pthread keys are more portable than __thread and allow the association
of a destructor with the key. Use the destructor to clean up TLS
callchain cursors to aid understanding memory leaks.

Committer notes:

Had to fixup a series of unconverted places and also check for the
return of get_tls_callchain_cursor() as it may fail and return NULL.

In that unlikely case we now either print something to a file, if the
caller was expecting to print a callchain, or return an error code to
state that resolving the callchain isn't possible.

In some cases this was made easier because thread__resolve_callchain()
already can fail for other reasons, so this new one (cursor == NULL) can
be added and the callers don't have to explicitely check for this new
condition.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ali Saidi <alisaidi@amazon.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Brian Robbins <brianrob@linux.microsoft.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: Dmitrii Dolgov <9erthalion6@gmail.com>
Cc: Fangrui Song <maskray@google.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Babrou <ivan@cloudflare.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Steinar H. Gunderson <sesse@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Wenyu Liu <liuwenyu7@huawei.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Ye Xingchen <ye.xingchen@zte.com.cn>
Cc: Yuan Can <yuancan@huawei.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230608232823.4027869-25-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/tools/perf/builtin-kwork.c b/tools/perf/builtin-kwork.c
index 2d80aef4eccc..14bf7a8429e7 100644
--- a/tools/perf/builtin-kwork.c
+++ b/tools/perf/builtin-kwork.c
@@ -589,7 +589,7 @@ static void timehist_save_callchain(struct perf_kwork *kwork,
 	struct symbol *sym;
 	struct thread *thread;
 	struct callchain_cursor_node *node;
-	struct callchain_cursor *cursor = &callchain_cursor;
+	struct callchain_cursor *cursor;
 
 	if (!kwork->show_callchain || sample->callchain == NULL)
 		return;
@@ -601,6 +601,8 @@ static void timehist_save_callchain(struct perf_kwork *kwork,
 		return;
 	}
 
+	cursor = get_tls_callchain_cursor();
+
 	if (thread__resolve_callchain(thread, cursor, evsel, sample,
 				      NULL, NULL, kwork->max_stack + 2) != 0) {
 		pr_debug("Failed to resolve callchain, skipping\n");
@@ -686,12 +688,18 @@ static void timehist_print_event(struct perf_kwork *kwork,
 	 * callchain
 	 */
 	if (kwork->show_callchain) {
+		struct callchain_cursor *cursor = get_tls_callchain_cursor();
+
+		if (cursor == NULL)
+			return;
+
 		printf(" ");
+
 		sample__fprintf_sym(sample, al, 0,
 				    EVSEL__PRINT_SYM | EVSEL__PRINT_ONELINE |
 				    EVSEL__PRINT_CALLCHAIN_ARROW |
 				    EVSEL__PRINT_SKIP_IGNORED,
-				    &callchain_cursor, symbol_conf.bt_stop_list,
+				    cursor, symbol_conf.bt_stop_list,
 				    stdout);
 	}