diff --git a/linker/dlfcn.cpp b/linker/dlfcn.cpp
index 98931c7..367179d 100644
--- a/linker/dlfcn.cpp
+++ b/linker/dlfcn.cpp
@@ -232,7 +232,7 @@
 static unsigned g_libdl_chains[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 0 };
 #endif
 
-static soinfo __libdl_info("libdl.so", nullptr, RTLD_GLOBAL);
+static soinfo __libdl_info("libdl.so", nullptr, 0, RTLD_GLOBAL);
 
 // This is used by the dynamic linker. Every process gets these symbols for free.
 soinfo* get_libdl_info() {
diff --git a/linker/linker.cpp b/linker/linker.cpp
index a8c2b1e..be2b45a 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -282,13 +282,13 @@
   g_soinfo_links_allocator.protect_all(protection);
 }
 
-static soinfo* soinfo_alloc(const char* name, struct stat* file_stat, int rtld_flags) {
+static soinfo* soinfo_alloc(const char* name, struct stat* file_stat, off64_t file_offset, int rtld_flags) {
   if (strlen(name) >= SOINFO_NAME_LEN) {
     DL_ERR("library name \"%s\" too long", name);
     return nullptr;
   }
 
-  soinfo* si = new (g_soinfo_allocator.alloc()) soinfo(name, file_stat, rtld_flags);
+  soinfo* si = new (g_soinfo_allocator.alloc()) soinfo(name, file_stat, file_offset, rtld_flags);
 
   sonext->next = si;
   sonext = si;
@@ -452,7 +452,7 @@
   return nullptr;
 }
 
-soinfo::soinfo(const char* name, const struct stat* file_stat, int rtld_flags) {
+soinfo::soinfo(const char* name, const struct stat* file_stat, off64_t file_offset, int rtld_flags) {
   memset(this, 0, sizeof(*this));
 
   strlcpy(this->name, name, sizeof(this->name));
@@ -460,8 +460,9 @@
   version = SOINFO_VERSION;
 
   if (file_stat != nullptr) {
-    set_st_dev(file_stat->st_dev);
-    set_st_ino(file_stat->st_ino);
+    this->st_dev = file_stat->st_dev;
+    this->st_ino = file_stat->st_ino;
+    this->file_offset = file_offset;
   }
 
   this->rtld_flags = rtld_flags;
@@ -781,10 +782,14 @@
 
 static soinfo* load_library(LoadTaskList& load_tasks, const char* name, int rtld_flags, const android_dlextinfo* extinfo) {
   int fd = -1;
+  off64_t file_offset = 0;
   ScopedFd file_guard(-1);
 
   if (extinfo != nullptr && (extinfo->flags & ANDROID_DLEXT_USE_LIBRARY_FD) != 0) {
     fd = extinfo->library_fd;
+    if ((extinfo->flags & ANDROID_DLEXT_USE_LIBRARY_OFFSET) != 0) {
+      file_offset = extinfo->library_offset;
+    }
   } else {
     // Open the file.
     fd = open_library(name);
@@ -796,6 +801,11 @@
     file_guard.reset(fd);
   }
 
+  if ((file_offset % PAGE_SIZE) != 0) {
+    DL_ERR("file offset for the library %s is not page-aligned: %" PRId64, name, file_offset);
+    return nullptr;
+  }
+
   struct stat file_stat;
   if (TEMP_FAILURE_RETRY(fstat(fd, &file_stat)) != 0) {
     DL_ERR("unable to stat file for the library %s: %s", name, strerror(errno));
@@ -808,7 +818,8 @@
     if (si->get_st_dev() != 0 &&
         si->get_st_ino() != 0 &&
         si->get_st_dev() == file_stat.st_dev &&
-        si->get_st_ino() == file_stat.st_ino) {
+        si->get_st_ino() == file_stat.st_ino &&
+        si->get_file_offset() == file_offset) {
       TRACE("library \"%s\" is already loaded under different name/path \"%s\" - will return existing soinfo", name, si->name);
       return si;
     }
@@ -820,12 +831,12 @@
   }
 
   // Read the ELF header and load the segments.
-  ElfReader elf_reader(name, fd);
+  ElfReader elf_reader(name, fd, file_offset);
   if (!elf_reader.Load(extinfo)) {
     return nullptr;
   }
 
-  soinfo* si = soinfo_alloc(SEARCH_NAME(name), &file_stat, rtld_flags);
+  soinfo* si = soinfo_alloc(SEARCH_NAME(name), &file_stat, file_offset, rtld_flags);
   if (si == nullptr) {
     return nullptr;
   }
@@ -1043,9 +1054,16 @@
     DL_ERR("invalid flags to dlopen: %x", flags);
     return nullptr;
   }
-  if (extinfo != nullptr && ((extinfo->flags & ~(ANDROID_DLEXT_VALID_FLAG_BITS)) != 0)) {
-    DL_ERR("invalid extended flags to android_dlopen_ext: %" PRIx64, extinfo->flags);
-    return nullptr;
+  if (extinfo != nullptr) {
+    if ((extinfo->flags & ~(ANDROID_DLEXT_VALID_FLAG_BITS)) != 0) {
+      DL_ERR("invalid extended flags to android_dlopen_ext: 0x%" PRIx64, extinfo->flags);
+      return nullptr;
+    }
+    if ((extinfo->flags & ANDROID_DLEXT_USE_LIBRARY_FD) == 0 &&
+        (extinfo->flags & ANDROID_DLEXT_USE_LIBRARY_OFFSET) != 0) {
+      DL_ERR("invalid extended flag combination (ANDROID_DLEXT_USE_LIBRARY_OFFSET without ANDROID_DLEXT_USE_LIBRARY_FD): 0x%" PRIx64, extinfo->flags);
+      return nullptr;
+    }
   }
   protect_data(PROT_READ | PROT_WRITE);
   soinfo* si = find_library(name, flags, extinfo);
@@ -1727,18 +1745,6 @@
   children.clear();
 }
 
-void soinfo::set_st_dev(dev_t dev) {
-  if (has_min_version(0)) {
-    st_dev = dev;
-  }
-}
-
-void soinfo::set_st_ino(ino_t ino) {
-  if (has_min_version(0)) {
-    st_ino = ino;
-  }
-}
-
 dev_t soinfo::get_st_dev() {
   if (has_min_version(0)) {
     return st_dev;
@@ -1755,6 +1761,14 @@
   return 0;
 }
 
+off64_t soinfo::get_file_offset() {
+  if (has_min_version(1)) {
+    return file_offset;
+  }
+
+  return 0;
+}
+
 int soinfo::get_rtld_flags() {
   if (has_min_version(1)) {
     return rtld_flags;
@@ -2242,7 +2256,7 @@
     return;
   }
 
-  soinfo* si = soinfo_alloc("[vdso]", nullptr, 0);
+  soinfo* si = soinfo_alloc("[vdso]", nullptr, 0, 0);
 
   si->phdr = reinterpret_cast<ElfW(Phdr)*>(reinterpret_cast<char*>(ehdr_vdso) + ehdr_vdso->e_phoff);
   si->phnum = ehdr_vdso->e_phnum;
@@ -2263,7 +2277,7 @@
 #else
 #define LINKER_PATH "/system/bin/linker"
 #endif
-static soinfo linker_soinfo_for_gdb(LINKER_PATH, nullptr, 0);
+static soinfo linker_soinfo_for_gdb(LINKER_PATH, nullptr, 0, 0);
 
 /* gdb expects the linker to be in the debug shared object list.
  * Without this, gdb has trouble locating the linker's ".text"
@@ -2327,7 +2341,7 @@
 
   INFO("[ android linker & debugger ]");
 
-  soinfo* si = soinfo_alloc(args.argv[0], nullptr, RTLD_GLOBAL);
+  soinfo* si = soinfo_alloc(args.argv[0], nullptr, 0, RTLD_GLOBAL);
   if (si == nullptr) {
     exit(EXIT_FAILURE);
   }
@@ -2515,7 +2529,7 @@
   ElfW(Ehdr)* elf_hdr = reinterpret_cast<ElfW(Ehdr)*>(linker_addr);
   ElfW(Phdr)* phdr = reinterpret_cast<ElfW(Phdr)*>(linker_addr + elf_hdr->e_phoff);
 
-  soinfo linker_so("[dynamic linker]", nullptr, 0);
+  soinfo linker_so("[dynamic linker]", nullptr, 0, 0);
 
   // If the linker is not acting as PT_INTERP entry_point is equal to
   // _start. Which means that the linker is running as an executable and
diff --git a/linker/linker.h b/linker/linker.h
index c8e5c68..08dd625 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -201,7 +201,7 @@
 #endif
   bool has_DT_SYMBOLIC;
 
-  soinfo(const char* name, const struct stat* file_stat, int rtld_flags);
+  soinfo(const char* name, const struct stat* file_stat, off64_t file_offset, int rtld_flags);
 
   void CallConstructors();
   void CallDestructors();
@@ -212,10 +212,9 @@
   void add_child(soinfo* child);
   void remove_all_links();
 
-  void set_st_dev(dev_t st_dev);
-  void set_st_ino(ino_t st_ino);
   ino_t get_st_ino();
   dev_t get_st_dev();
+  off64_t get_file_offset();
 
   int get_rtld_flags();
 
@@ -254,6 +253,7 @@
   soinfo_list_t parents;
 
   // version >= 1
+  off64_t file_offset;
   int rtld_flags;
   size_t strtab_size;
 
diff --git a/linker/linker_phdr.cpp b/linker/linker_phdr.cpp
index 44c8e9e..e0d6d0e 100644
--- a/linker/linker_phdr.cpp
+++ b/linker/linker_phdr.cpp
@@ -119,8 +119,8 @@
                                       MAYBE_MAP_FLAG((x), PF_R, PROT_READ) | \
                                       MAYBE_MAP_FLAG((x), PF_W, PROT_WRITE))
 
-ElfReader::ElfReader(const char* name, int fd)
-    : name_(name), fd_(fd),
+ElfReader::ElfReader(const char* name, int fd, off64_t file_offset)
+    : name_(name), fd_(fd), file_offset_(file_offset),
       phdr_num_(0), phdr_mmap_(nullptr), phdr_table_(nullptr), phdr_size_(0),
       load_start_(nullptr), load_size_(0), load_bias_(0),
       loaded_phdr_(nullptr) {
@@ -142,6 +142,13 @@
 }
 
 bool ElfReader::ReadElfHeader() {
+  off64_t actual_offset = lseek64(fd_, file_offset_, SEEK_SET);
+
+  if (actual_offset != file_offset_) {
+    DL_ERR("seek to %" PRId64 " failed: %s", file_offset_, strerror(errno));
+    return false;
+  }
+
   ssize_t rc = TEMP_FAILURE_RETRY(read(fd_, &header_, sizeof(header_)));
   if (rc < 0) {
     DL_ERR("can't read file \"%s\": %s", name_, strerror(errno));
@@ -225,7 +232,7 @@
 
   phdr_size_ = page_max - page_min;
 
-  void* mmap_result = mmap(nullptr, phdr_size_, PROT_READ, MAP_PRIVATE, fd_, page_min);
+  void* mmap_result = mmap64(nullptr, phdr_size_, PROT_READ, MAP_PRIVATE, fd_, file_offset_ + page_min);
   if (mmap_result == MAP_FAILED) {
     DL_ERR("\"%s\" phdr mmap failed: %s", name_, strerror(errno));
     return false;
@@ -356,12 +363,12 @@
     ElfW(Addr) file_length = file_end - file_page_start;
 
     if (file_length != 0) {
-      void* seg_addr = mmap(reinterpret_cast<void*>(seg_page_start),
+      void* seg_addr = mmap64(reinterpret_cast<void*>(seg_page_start),
                             file_length,
                             PFLAGS_TO_PROT(phdr->p_flags),
                             MAP_FIXED|MAP_PRIVATE,
                             fd_,
-                            file_page_start);
+                            file_offset_ + file_page_start);
       if (seg_addr == MAP_FAILED) {
         DL_ERR("couldn't map \"%s\" segment %zd: %s", name_, i, strerror(errno));
         return false;
diff --git a/linker/linker_phdr.h b/linker/linker_phdr.h
index 593fb5a..65d302c 100644
--- a/linker/linker_phdr.h
+++ b/linker/linker_phdr.h
@@ -39,7 +39,7 @@
 
 class ElfReader {
  public:
-  ElfReader(const char* name, int fd);
+  ElfReader(const char* name, int fd, off64_t file_offset);
   ~ElfReader();
 
   bool Load(const android_dlextinfo* extinfo);
@@ -61,6 +61,7 @@
 
   const char* name_;
   int fd_;
+  off64_t file_offset_;
 
   ElfW(Ehdr) header_;
   size_t phdr_num_;