logd: klogd crash (part deux)

LogBuffer::pidToUid(pid_t pid) { return stats.pidToUid(pid); }
needs to have LogBuffer::lock()/unlock() to prevent unordered_map
data corruption. This can lead to multiple symptoms, crashes and
continuous spins on corrupted iterators.

Bug: 30688716
Bug: 30050636
Bug: 30614675
Bug: 25620123
Bug: 30792935
Change-Id: I1d8fec8e5fda98c6a08645e7456b081507696b3c
diff --git a/logd/LogKlog.cpp b/logd/LogKlog.cpp
index 0495463..ef6c1ae 100644
--- a/logd/LogKlog.cpp
+++ b/logd/LogKlog.cpp
@@ -26,6 +26,7 @@
 #include <syslog.h>
 
 #include <log/logger.h>
+#include <private/android_filesystem_config.h>
 
 #include "LogBuffer.h"
 #include "LogKlog.h"
@@ -589,7 +590,12 @@
     // Parse pid, tid and uid
     const pid_t pid = sniffPid(p, len - (p - buf));
     const pid_t tid = pid;
-    const uid_t uid = pid ? logbuf->pidToUid(pid) : 0;
+    uid_t uid = AID_ROOT;
+    if (pid) {
+        logbuf->lock();
+        uid = logbuf->pidToUid(pid);
+        logbuf->unlock();
+    }
 
     // Parse (rules at top) to pull out a tag from the incoming kernel message.
     // Some may view the following as an ugly heuristic, the desire is to