perf addr_location: Add init/exit/copy functions

struct addr_location holds references to multiple reference counted
objects. Add init/exit functions to make maintenance of those more
consistent with the rest of the code and to try to avoid
leaks. Modification of thread reference counts isn't included in this
change.

Committer notes:

I needed to initialize result to sample->ip to make sure is set to
something, fixing a compile time error, mostly keeping the previous
logic as build_alloc_func_list() already does debugging/error prints
about what went wrong if it takes the 'goto out'.

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/20230608232823.4027869-7-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 17 insertions, 4 deletions

diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c
index 3723b5e31b2a..83eea968482e 100644
--- a/tools/perf/util/unwind-libdw.c
+++ b/tools/perf/util/unwind-libdw.c
@@ -90,8 +90,12 @@ static int __report_module(struct addr_location *al, u64 ip,
 static int report_module(u64 ip, struct unwind_info *ui)
 {
 	struct addr_location al;
+	int res;
 
-	return __report_module(&al, ip, ui);
+	addr_location__init(&al);
+	res = __report_module(&al, ip, ui);
+	addr_location__exit(&al);
+	return res;
 }
 
 /*
@@ -104,8 +108,11 @@ static int entry(u64 ip, struct unwind_info *ui)
 	struct unwind_entry *e = &ui->entries[ui->idx++];
 	struct addr_location al;
 
-	if (__report_module(&al, ip, ui))
+	addr_location__init(&al);
+	if (__report_module(&al, ip, ui)) {
+		addr_location__exit(&al);
 		return -1;
+	}
 
 	e->ip	  = ip;
 	e->ms.maps = al.maps;
@@ -116,6 +123,7 @@ static int entry(u64 ip, struct unwind_info *ui)
 		 al.sym ? al.sym->name : "''",
 		 ip,
 		 al.map ? map__map_ip(al.map, ip) : (u64) 0);
+	addr_location__exit(&al);
 	return 0;
 }
 
@@ -136,17 +144,22 @@ static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr,
 	ssize_t size;
 	struct dso *dso;
 
+	addr_location__init(&al);
 	if (!thread__find_map(ui->thread, PERF_RECORD_MISC_USER, addr, &al)) {
 		pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
-		return -1;
+		goto out_fail;
 	}
 	dso = map__dso(al.map);
 	if (!dso)
-		return -1;
+		goto out_fail;
 
 	size = dso__data_read_addr(dso, al.map, ui->machine, addr, (u8 *) data, sizeof(*data));
 
+	addr_location__exit(&al);
 	return !(size == sizeof(*data));
+out_fail:
+	addr_location__exit(&al);
+	return -1;
 }
 
 static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *result,