From 7fd6c5c6f5f55e680a67cd9ca949f9c85b0ac0d0 Mon Sep 17 00:00:00 2001
From: Mark Salyzyn <salyzyn@google.com>
Date: Tue, 19 Jan 2016 16:04:41 -0800
Subject: [PATCH] logd: prune maintain per-id watermark (part deux)

iterator corruption as we allow mLast to slip through the FIFO

Bug: 23685592
Bug: 26646087
Change-Id: Ifcbaecf390ee47b195c3d823d080c66c15db4530
---
 logd/LogBuffer.cpp | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/logd/LogBuffer.cpp b/logd/LogBuffer.cpp
index cdf5d08fb..9e0d4515b 100644
--- a/logd/LogBuffer.cpp
+++ b/logd/LogBuffer.cpp
@@ -332,13 +332,21 @@ LogBufferElementCollection::iterator LogBuffer::erase(
         }
     }
 
-    bool setLast = mLastSet[id] && (it == mLast[id]);
+    bool setLast[LOG_ID_MAX];
+    bool doSetLast = false;
+    log_id_for_each(i) {
+        doSetLast |= setLast[i] = mLastSet[i] && (it == mLast[i]);
+    }
     it = mLogElements.erase(it);
-    if (setLast) {
-        if (it == mLogElements.end()) { // unlikely
-            mLastSet[id] = false;
-        } else {
-            mLast[id] = it;
+    if (doSetLast) {
+        log_id_for_each(i) {
+            if (setLast[i]) {
+                if (it == mLogElements.end()) { // unlikely
+                    mLastSet[i] = false;
+                } else {
+                    mLast[i] = it;
+                }
+            }
         }
     }
     if (coalesce) {