From: xie xingguo <xie.xingguo@zte.com.cn>
Date: Sat, 18 Aug 2018 09:17:01 +0000 (+0800)
Subject: osd/PGLog: trim - avoid dereferencing invalid iter
X-Git-Tag: v14.0.1~444^2
X-Git-Url: http://git.apps.os.sepia.ceph.com/?a=commitdiff_plain;h=19a5c375e6efcd83532fa3534c35dbf768a678ea;p=ceph.git

osd/PGLog: trim - avoid dereferencing invalid iter

Log(e.g., projected_log) could theoretically be emtpy and hence there might
be potential access violation.

Signed-off-by: xie xingguo <xie.xingguo@zte.com.cn>
---

diff --git a/src/osd/PGLog.cc b/src/osd/PGLog.cc
index eb88dc1db3c52..0d9d73e598058 100644
--- a/src/osd/PGLog.cc
+++ b/src/osd/PGLog.cc
@@ -100,9 +100,13 @@ void PGLog::IndexedLog::trim(
 
     // reset complete_to to the beginning of the log
     if (reset_complete_to) {
-      lgeneric_subdout(cct, osd, 20) << " moving complete_to " << " to "
-                      << log.begin()->version << dendl;
       complete_to = log.begin();
+      if (complete_to != log.end()) {
+        lgeneric_subdout(cct, osd, 20) << " moving complete_to to "
+                                       << log.begin()->version << dendl;
+      } else {
+        lgeneric_subdout(cct, osd, 20) << " log is now empty" << dendl;
+      }
     }
   }