[PATCH v3 14/18] perf dso: Hold lock when accessing nsinfo

[Ian Rogers <irogers@google.com>]

There may be threads racing to update dso->nsinfo:
https://lore.kernel.org/linux-perf-users/CAP-5=fWZH20L4kv-BwVtGLwR=Em3AOOT+Q4QGivvQuYn5AsPRg@mail.gmail.com/
Holding the dso->lock avoids use-after-free, memory leaks and other
such bugs. Apply the fix in:
https://lore.kernel.org/linux-perf-users/20211118193714.2293728-1-irogers@google.com/
of there being a missing nsinfo__put now that the accesses are data race
free. Fixes test "Lookup mmap thread" when compiled with address
sanitizer.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/builtin-inject.c   |  4 ++++
 tools/perf/util/annotate.c    |  2 ++
 tools/perf/util/build-id.c    | 12 +++++++++---
 tools/perf/util/dso.c         |  7 ++++++-
 tools/perf/util/map.c         |  3 +++
 tools/perf/util/probe-event.c |  3 +++
 tools/perf/util/symbol.c      |  2 +-
 7 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index 8ec955402488..e254f18986f7 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -436,8 +436,10 @@ static struct dso *findnew_dso(int pid, int tid, const char *filename,
 	}
 
 	if (dso) {
+		mutex_lock(&dso->lock);
 		nsinfo__put(dso->nsinfo);
 		dso->nsinfo = nsi;
+		mutex_unlock(&dso->lock);
 	} else
 		nsinfo__put(nsi);
 
@@ -620,6 +622,7 @@ static int dso__read_build_id(struct dso *dso)
 	if (dso->has_build_id)
 		return 0;
 
+	mutex_lock(&dso->lock);
 	nsinfo__mountns_enter(dso->nsinfo, &nsc);
 	if (filename__read_build_id(dso->long_name, &dso->bid) > 0)
 		dso->has_build_id = true;
@@ -633,6 +636,7 @@ static int dso__read_build_id(struct dso *dso)
 		free(new_name);
 	}
 	nsinfo__mountns_exit(&nsc);
+	mutex_unlock(&dso->lock);
 
 	return dso->has_build_id ? 0 : -1;
 }
diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 9d7dd6489a05..5bc63c9e0324 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -1697,6 +1697,7 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
 		 */
 		__symbol__join_symfs(filename, filename_size, dso->long_name);
 
+		mutex_lock(&dso->lock);
 		if (access(filename, R_OK) && errno == ENOENT && dso->nsinfo) {
 			char *new_name = filename_with_chroot(dso->nsinfo->pid,
 							      filename);
@@ -1705,6 +1706,7 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
 				free(new_name);
 			}
 		}
+		mutex_unlock(&dso->lock);
 	}
 
 	free(build_id_path);
diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index ec18ed5caf3e..a839b30c981b 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -898,11 +898,15 @@ static int filename__read_build_id_ns(const char *filename,
 static bool dso__build_id_mismatch(struct dso *dso, const char *name)
 {
 	struct build_id bid;
+	bool ret = false;
 
-	if (filename__read_build_id_ns(name, &bid, dso->nsinfo) < 0)
-		return false;
+	mutex_lock(&dso->lock);
+	if (filename__read_build_id_ns(name, &bid, dso->nsinfo) >= 0)
+		ret = !dso__build_id_equal(dso, &bid);
 
-	return !dso__build_id_equal(dso, &bid);
+	mutex_unlock(&dso->lock);
+
+	return ret;
 }
 
 static int dso__cache_build_id(struct dso *dso, struct machine *machine,
@@ -941,8 +945,10 @@ static int dso__cache_build_id(struct dso *dso, struct machine *machine,
 	if (!is_kallsyms && dso__build_id_mismatch(dso, name))
 		goto out_free;
 
+	mutex_lock(&dso->lock);
 	ret = build_id_cache__add_b(&dso->bid, name, dso->nsinfo,
 				    is_kallsyms, is_vdso, proper_name, root_dir);
+	mutex_unlock(&dso->lock);
 out_free:
 	free(allocated_name);
 	return ret;
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index a9789a955403..f1a14c0ad26d 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -501,6 +501,7 @@ static int __open_dso(struct dso *dso, struct machine *machine)
 	if (!name)
 		return -ENOMEM;
 
+	mutex_lock(&dso->lock);
 	if (machine)
 		root_dir = machine->root_dir;
 
@@ -541,6 +542,7 @@ static int __open_dso(struct dso *dso, struct machine *machine)
 		unlink(name);
 
 out:
+	mutex_unlock(&dso->lock);
 	free(name);
 	return fd;
 }
@@ -559,8 +561,11 @@ static int open_dso(struct dso *dso, struct machine *machine)
 	int fd;
 	struct nscookie nsc;
 
-	if (dso->binary_type != DSO_BINARY_TYPE__BUILD_ID_CACHE)
+	if (dso->binary_type != DSO_BINARY_TYPE__BUILD_ID_CACHE) {
+		mutex_lock(&dso->lock);
 		nsinfo__mountns_enter(dso->nsinfo, &nsc);
+		mutex_unlock(&dso->lock);
+	}
 	fd = __open_dso(dso, machine);
 	if (dso->binary_type != DSO_BINARY_TYPE__BUILD_ID_CACHE)
 		nsinfo__mountns_exit(&nsc);
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index e0aa4a254583..f3a3d9b3a40d 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -181,7 +181,10 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
 			if (!(prot & PROT_EXEC))
 				dso__set_loaded(dso);
 		}
+		mutex_lock(&dso->lock);
+		nsinfo__put(dso->nsinfo);
 		dso->nsinfo = nsi;
+		mutex_unlock(&dso->lock);
 
 		if (build_id__is_defined(bid)) {
 			dso__set_build_id(dso, bid);
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 785246ff4179..0c24bc7afbca 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -29,6 +29,7 @@
 #include "color.h"
 #include "map.h"
 #include "maps.h"
+#include "mutex.h"
 #include "symbol.h"
 #include <api/fs/fs.h>
 #include "trace-event.h"	/* For __maybe_unused */
@@ -180,8 +181,10 @@ struct map *get_target_map(const char *target, struct nsinfo *nsi, bool user)
 
 		map = dso__new_map(target);
 		if (map && map->dso) {
+			mutex_lock(&map->dso->lock);
 			nsinfo__put(map->dso->nsinfo);
 			map->dso->nsinfo = nsinfo__get(nsi);
+			mutex_unlock(&map->dso->lock);
 		}
 		return map;
 	} else {
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 656d9b4dd456..a3a165ae933a 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1791,6 +1791,7 @@ int dso__load(struct dso *dso, struct map *map)
 	char newmapname[PATH_MAX];
 	const char *map_path = dso->long_name;
 
+	mutex_lock(&dso->lock);
 	perfmap = strncmp(dso->name, "/tmp/perf-", 10) == 0;
 	if (perfmap) {
 		if (dso->nsinfo && (dso__find_perf_map(newmapname,
@@ -1800,7 +1801,6 @@ int dso__load(struct dso *dso, struct map *map)
 	}
 
 	nsinfo__mountns_enter(dso->nsinfo, &nsc);
-	mutex_lock(&dso->lock);
 
 	/* check again under the dso->lock */
 	if (dso__loaded(dso)) {
-- 
2.37.2.609.g9ff673ca1a-goog