logd: serialize accesses to stats helpers

Quick low-risk to resolve possible hash table corruption.
Resolved an unlikely path memory leak.

ToDo: replace lock with nested lock so no lock
      helpers are required.

Bug: 22068332
Change-Id: I303ab06608502c7d61d42f111a9c43366f184d0c

1 files changed, 3 insertions, 1 deletions

diff --git a/logd/LogBuffer.h b/logd/LogBuffer.h
index 00b19b67b..a13fded8b 100644
--- a/logd/LogBuffer.h
+++ b/logd/LogBuffer.h
@@ -71,10 +71,12 @@ public:
     // *strp uses malloc, use free to release.
     void formatPrune(char **strp) { mPrune.format(strp); }
 
-    // helper
+    // helper must be protected directly or implicitly by lock()/unlock()
     char *pidToName(pid_t pid) { return stats.pidToName(pid); }
     uid_t pidToUid(pid_t pid) { return stats.pidToUid(pid); }
     char *uidToName(uid_t uid) { return stats.uidToName(uid); }
+    void lock() { pthread_mutex_lock(&mLogElementsLock); }
+    void unlock() { pthread_mutex_unlock(&mLogElementsLock); }
 
 private:
     void maybePrune(log_id_t id);