From: Joao Eduardo Luis <joao@suse.de>
Date: Mon, 17 Jul 2017 14:41:49 +0000 (+0100)
Subject: mon/LogMonitor: don't read list's end() for log last
X-Git-Tag: v12.1.2~221^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=67998dbeae8fa1046bf282ce4bd2b55229648fdf;p=ceph.git

mon/LogMonitor: don't read list's end() for log last

We will assert semi-randomly if we read the end of the list, which is
not a real element. Instead, walk the list in reverse.

Signed-off-by: Joao Eduardo Luis <joao@suse.de>
---

diff --git a/src/mon/LogMonitor.cc b/src/mon/LogMonitor.cc
index 20fc1332763a..c7c2b281b48c 100644
--- a/src/mon/LogMonitor.cc
+++ b/src/mon/LogMonitor.cc
@@ -428,14 +428,15 @@ bool LogMonitor::preprocess_command(MonOpRequestRef op)
       return entry.prio >= level && (entry.channel == channel || channel == "*");
     };
 
-    auto p = summary.tail.end();
-    while (num > 0 && p != summary.tail.begin()) {
-      if (match(*p)) {
+    auto rp = summary.tail.rbegin();
+    while (num > 0 && rp != summary.tail.rend()) {
+      if (match(*rp)) {
         num--;
       }
-      --p;
+      ++rp;
     }
     ostringstream ss;
+    auto p = summary.tail.begin();
     for ( ; p != summary.tail.end(); ++p) {
       if (!match(*p)) {
         continue;