diff -Nru apt-0.8.16~exp12ubuntu10.24/apt-pkg/deb/debindexfile.cc apt-0.8.16~exp12ubuntu10.25/apt-pkg/deb/debindexfile.cc
--- apt-0.8.16~exp12ubuntu10.24/apt-pkg/deb/debindexfile.cc	2013-04-10 20:31:54.000000000 +0000
+++ apt-0.8.16~exp12ubuntu10.25/apt-pkg/deb/debindexfile.cc	2015-07-22 11:40:00.000000000 +0000
@@ -602,7 +602,8 @@
    pkgCache::PkgFileIterator CFile = Gen.GetCurFile();
    CFile->Size = Pkg.FileSize();
    CFile->mtime = Pkg.ModificationTime();
-   CFile->Archive = Gen.WriteUniqString("now");
+   map_ptrloc const storage = Gen.WriteUniqString("now");
+   CFile->Archive = storage;
    
    if (Gen.MergeList(Parser) == false)
       return _error->Error("Problem with MergeList %s",File.c_str());   
diff -Nru apt-0.8.16~exp12ubuntu10.24/apt-pkg/deb/deblistparser.cc apt-0.8.16~exp12ubuntu10.25/apt-pkg/deb/deblistparser.cc
--- apt-0.8.16~exp12ubuntu10.24/apt-pkg/deb/deblistparser.cc	2013-04-10 20:31:54.000000000 +0000
+++ apt-0.8.16~exp12ubuntu10.25/apt-pkg/deb/deblistparser.cc	2015-07-22 11:40:37.000000000 +0000
@@ -100,7 +100,8 @@
 bool debListParser::NewVersion(pkgCache::VerIterator &Ver)
 {
    // Parse the section
-   Ver->Section = UniqFindTagWrite("Section");
+   unsigned long const idxSection = UniqFindTagWrite("Section");
+   Ver->Section = idxSection;
 
    // Parse multi-arch
    string const MultiArch = Section.FindS("Multi-Arch");
@@ -234,7 +235,10 @@
 			       pkgCache::VerIterator &Ver)
 {
    if (Pkg->Section == 0)
-      Pkg->Section = UniqFindTagWrite("Section");
+   {
+      unsigned long const idxSection = UniqFindTagWrite("Section");
+      Pkg->Section = idxSection;
+   }
 
    // Packages which are not from the "native" arch doesn't get the essential flag
    // in the default "native" mode - it is also possible to mark "all" or "none".
@@ -771,7 +775,8 @@
 {
    // apt-secure does no longer download individual (per-section) Release
    // file. to provide Component pinning we use the section name now
-   FileI->Component = WriteUniqString(component);
+   map_ptrloc const storage = WriteUniqString(component);
+   FileI->Component = storage;
 
    // FIXME: Code depends on the fact that Release files aren't compressed
    FILE* release = fdopen(dup(File.Fd()), "r");
@@ -858,13 +863,14 @@
 	       break;
 	    *s = '\0';
 	 }
+	 map_ptrloc const storage = WriteUniqString(data);
 	 switch (writeTo) {
-	 case Suite: FileI->Archive = WriteUniqString(data); break;
-	 case Component: FileI->Component = WriteUniqString(data); break;
-	 case Version: FileI->Version = WriteUniqString(data); break;
-	 case Origin: FileI->Origin = WriteUniqString(data); break;
-	 case Codename: FileI->Codename = WriteUniqString(data); break;
-	 case Label: FileI->Label = WriteUniqString(data); break;
+	 case Suite: FileI->Archive = storage; break;
+	 case Component: FileI->Component = storage; break;
+	 case Version: FileI->Version = storage; break;
+	 case Origin: FileI->Origin = storage; break;
+	 case Codename: FileI->Codename = storage; break;
+	 case Label: FileI->Label = storage; break;
 	 case None: break;
 	 }
       }
diff -Nru apt-0.8.16~exp12ubuntu10.24/apt-pkg/edsp/edspindexfile.cc apt-0.8.16~exp12ubuntu10.25/apt-pkg/edsp/edspindexfile.cc
--- apt-0.8.16~exp12ubuntu10.24/apt-pkg/edsp/edspindexfile.cc	2013-04-10 20:31:54.000000000 +0000
+++ apt-0.8.16~exp12ubuntu10.25/apt-pkg/edsp/edspindexfile.cc	2015-07-22 11:41:00.000000000 +0000
@@ -51,7 +51,8 @@
    pkgCache::PkgFileIterator CFile = Gen.GetCurFile();
    CFile->Size = Pkg.FileSize();
    CFile->mtime = Pkg.ModificationTime();
-   CFile->Archive = Gen.WriteUniqString("edsp::scenario");
+   map_ptrloc const storage = Gen.WriteUniqString("edsp::scenario");
+   CFile->Archive = storage;
 
    if (Gen.MergeList(Parser) == false)
       return _error->Error("Problem with MergeList %s",File.c_str());
diff -Nru apt-0.8.16~exp12ubuntu10.24/debian/changelog apt-0.8.16~exp12ubuntu10.25/debian/changelog
--- apt-0.8.16~exp12ubuntu10.24/debian/changelog	2015-05-20 14:30:42.000000000 +0000
+++ apt-0.8.16~exp12ubuntu10.25/debian/changelog	2015-07-22 12:16:39.000000000 +0000
@@ -1,3 +1,15 @@
+apt (0.8.16~exp12ubuntu10.25) precise; urgency=medium
+
+  * Backport patches from David Kalnischkies to fix crashes with dynamic
+    cache remapping (LP: #957231):
+    - Do not dereference the storage for the unique strings as the pointer
+      can change at the time of writing the strings, so first store it
+      temporary and then save the index in the (possibly new) pointer
+      location
+    - Handle moved mmap after UniqFindTagWrite call (Closes: #753941)
+
+ -- Colin Watson <cjwatson@ubuntu.com>  Wed, 22 Jul 2015 13:16:37 +0100
+
 apt (0.8.16~exp12ubuntu10.24) precise-proposed; urgency=low
 
   * fix crash for packages that have no section in their instVersion