diff --git a/libc/Android.bp b/libc/Android.bp
index 8c9420f..6c2ca17 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -1421,6 +1421,7 @@
         "bionic/pthread_getcpuclockid.cpp",
         "bionic/pthread_getschedparam.cpp",
         "bionic/pthread_gettid_np.cpp",
+        "bionic/pthread_internal.cpp",
         "bionic/pthread_join.cpp",
         "bionic/pthread_key.cpp",
         "bionic/pthread_kill.cpp",
diff --git a/libc/bionic/libc_init_common.cpp b/libc/bionic/libc_init_common.cpp
index 55a2e77..e5654c3 100644
--- a/libc/bionic/libc_init_common.cpp
+++ b/libc/bionic/libc_init_common.cpp
@@ -114,6 +114,10 @@
   __check_max_thread_id();
 #endif
 
+  // Get the main thread from TLS and add it to the thread list.
+  pthread_internal_t* main_thread = __get_thread();
+  __pthread_internal_add(main_thread);
+
   // Register atfork handlers to take and release the arc4random lock.
   pthread_atfork(arc4random_fork_handler, _thread_arc4_unlock, _thread_arc4_unlock);
 
diff --git a/libc/bionic/pthread_create.cpp b/libc/bionic/pthread_create.cpp
index a120365..bfa4e8c 100644
--- a/libc/bionic/pthread_create.cpp
+++ b/libc/bionic/pthread_create.cpp
@@ -115,13 +115,6 @@
   return error;
 }
 
-void __free_thread(pthread_internal_t* thread) {
-  if (thread->mmap_size != 0) {
-    // Free mapped space, including thread stack and pthread_internal_t.
-    munmap(thread->attr.stack_base, thread->mmap_size);
-  }
-}
-
 static void* __create_thread_mapped_space(size_t mmap_size, size_t stack_guard_size) {
   // Create a new private anonymous map.
   int prot = PROT_READ | PROT_WRITE;
@@ -272,7 +265,9 @@
     // be unblocked, but we're about to unmap the memory the mutex is stored in, so this serves as a
     // reminder that you can't rewrite this function to use a ScopedPthreadMutexLocker.
     thread->startup_handshake_lock.unlock();
-    __free_thread(thread);
+    if (thread->mmap_size != 0) {
+      munmap(thread->attr.stack_base, thread->mmap_size);
+    }
     __libc_format_log(ANDROID_LOG_WARN, "libc", "pthread_create failed: clone failed: %s", strerror(errno));
     return clone_errno;
   }
@@ -282,13 +277,14 @@
     // Mark the thread detached and replace its start_routine with a no-op.
     // Letting the thread run is the easiest way to clean up its resources.
     atomic_store(&thread->join_state, THREAD_DETACHED);
+    __pthread_internal_add(thread);
     thread->start_routine = __do_nothing;
     thread->startup_handshake_lock.unlock();
     return init_errno;
   }
 
   // Publish the pthread_t and unlock the mutex to let the new thread start running.
-  *thread_out = reinterpret_cast<pthread_t>(thread);
+  *thread_out = __pthread_internal_add(thread);
   thread->startup_handshake_lock.unlock();
 
   return 0;
diff --git a/libc/bionic/pthread_detach.cpp b/libc/bionic/pthread_detach.cpp
index 78d3a67..fb8e0dd 100644
--- a/libc/bionic/pthread_detach.cpp
+++ b/libc/bionic/pthread_detach.cpp
@@ -32,7 +32,10 @@
 #include "pthread_internal.h"
 
 int pthread_detach(pthread_t t) {
-  pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(t);
+  pthread_internal_t* thread = __pthread_internal_find(t);
+  if (thread == NULL) {
+    return ESRCH;
+  }
 
   ThreadJoinState old_state = THREAD_NOT_JOINED;
   while (old_state == THREAD_NOT_JOINED &&
diff --git a/libc/bionic/pthread_exit.cpp b/libc/bionic/pthread_exit.cpp
index ab1fb56..3401ed7 100644
--- a/libc/bionic/pthread_exit.cpp
+++ b/libc/bionic/pthread_exit.cpp
@@ -104,6 +104,9 @@
     // because we'll have freed the memory before the thread actually exits.
     __set_tid_address(NULL);
 
+    // pthread_internal_t is freed below with stack, not here.
+    __pthread_internal_remove(thread);
+
     if (thread->mmap_size != 0) {
       // We need to free mapped space for detached threads when they exit.
       // That's not something we can do in C.
diff --git a/libc/bionic/pthread_getcpuclockid.cpp b/libc/bionic/pthread_getcpuclockid.cpp
index 8bad566..2bf2004 100644
--- a/libc/bionic/pthread_getcpuclockid.cpp
+++ b/libc/bionic/pthread_getcpuclockid.cpp
@@ -31,7 +31,10 @@
 #include "pthread_internal.h"
 
 int pthread_getcpuclockid(pthread_t t, clockid_t* clockid) {
-  pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(t);
+  pthread_internal_t* thread = __pthread_internal_find(t);
+  if (thread == NULL) {
+    return ESRCH;
+  }
 
   // The tid is stored in the top bits, but negated.
   clockid_t result = ~static_cast<clockid_t>(thread->tid) << 3;
diff --git a/libc/bionic/pthread_getschedparam.cpp b/libc/bionic/pthread_getschedparam.cpp
index 39d098b..052fb05 100644
--- a/libc/bionic/pthread_getschedparam.cpp
+++ b/libc/bionic/pthread_getschedparam.cpp
@@ -34,7 +34,10 @@
 int pthread_getschedparam(pthread_t t, int* policy, sched_param* param) {
   ErrnoRestorer errno_restorer;
 
-  pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(t);
+  pthread_internal_t* thread = __pthread_internal_find(t);
+  if (thread == NULL) {
+    return ESRCH;
+  }
 
   int rc = sched_getparam(thread->tid, param);
   if (rc == -1) {
diff --git a/libc/bionic/pthread_internal.cpp b/libc/bionic/pthread_internal.cpp
new file mode 100644
index 0000000..8946f79
--- /dev/null
+++ b/libc/bionic/pthread_internal.cpp
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "pthread_internal.h"
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+
+#include "private/bionic_futex.h"
+#include "private/bionic_tls.h"
+#include "private/libc_logging.h"
+#include "private/ScopedPthreadMutexLocker.h"
+
+static pthread_internal_t* g_thread_list = NULL;
+static pthread_mutex_t g_thread_list_lock = PTHREAD_MUTEX_INITIALIZER;
+
+pthread_t __pthread_internal_add(pthread_internal_t* thread) {
+  ScopedPthreadMutexLocker locker(&g_thread_list_lock);
+
+  // We insert at the head.
+  thread->next = g_thread_list;
+  thread->prev = NULL;
+  if (thread->next != NULL) {
+    thread->next->prev = thread;
+  }
+  g_thread_list = thread;
+  return reinterpret_cast<pthread_t>(thread);
+}
+
+void __pthread_internal_remove(pthread_internal_t* thread) {
+  ScopedPthreadMutexLocker locker(&g_thread_list_lock);
+
+  if (thread->next != NULL) {
+    thread->next->prev = thread->prev;
+  }
+  if (thread->prev != NULL) {
+    thread->prev->next = thread->next;
+  } else {
+    g_thread_list = thread->next;
+  }
+}
+
+static void __pthread_internal_free(pthread_internal_t* thread) {
+  if (thread->mmap_size != 0) {
+    // Free mapped space, including thread stack and pthread_internal_t.
+    munmap(thread->attr.stack_base, thread->mmap_size);
+  }
+}
+
+void __pthread_internal_remove_and_free(pthread_internal_t* thread) {
+  __pthread_internal_remove(thread);
+  __pthread_internal_free(thread);
+}
+
+pthread_internal_t* __pthread_internal_find(pthread_t thread_id) {
+  pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(thread_id);
+
+  // check if thread is pthread_self() before acquiring the lock
+  if (thread == __get_thread()) {
+    return thread;
+  }
+
+  ScopedPthreadMutexLocker locker(&g_thread_list_lock);
+
+  for (pthread_internal_t* t = g_thread_list; t != NULL; t = t->next) {
+    if (t == thread) {
+      return thread;
+    }
+  }
+  return NULL;
+}
diff --git a/libc/bionic/pthread_internal.h b/libc/bionic/pthread_internal.h
index e40f5a4..d2abea0 100644
--- a/libc/bionic/pthread_internal.h
+++ b/libc/bionic/pthread_internal.h
@@ -56,12 +56,10 @@
 class thread_local_dtor;
 
 class pthread_internal_t {
-  // These two fields preserve backwards compatibility for code accessing the `tid` field,
-  // since we didn't always offer pthread_gettid_np.
-  void* unused0 __unused;
-  void* unused1 __unused;
-
  public:
+  class pthread_internal_t* next;
+  class pthread_internal_t* prev;
+
   pid_t tid;
 
  private:
@@ -114,13 +112,16 @@
   char dlerror_buffer[__BIONIC_DLERROR_BUFFER_SIZE];
 };
 
-__LIBC_HIDDEN__ int __init_thread(pthread_internal_t*);
-__LIBC_HIDDEN__ void __free_thread(pthread_internal_t*);
-
-__LIBC_HIDDEN__ void __init_tls(pthread_internal_t*);
-__LIBC_HIDDEN__ void __init_thread_stack_guard(pthread_internal_t*);
+__LIBC_HIDDEN__ int __init_thread(pthread_internal_t* thread);
+__LIBC_HIDDEN__ void __init_tls(pthread_internal_t* thread);
+__LIBC_HIDDEN__ void __init_thread_stack_guard(pthread_internal_t* thread);
 __LIBC_HIDDEN__ void __init_alternate_signal_stack(pthread_internal_t*);
 
+__LIBC_HIDDEN__ pthread_t           __pthread_internal_add(pthread_internal_t* thread);
+__LIBC_HIDDEN__ pthread_internal_t* __pthread_internal_find(pthread_t pthread_id);
+__LIBC_HIDDEN__ void                __pthread_internal_remove(pthread_internal_t* thread);
+__LIBC_HIDDEN__ void                __pthread_internal_remove_and_free(pthread_internal_t* thread);
+
 // Make __get_thread() inlined for performance reason. See http://b/19825434.
 static inline __always_inline pthread_internal_t* __get_thread() {
   void** tls = __get_tls();
diff --git a/libc/bionic/pthread_join.cpp b/libc/bionic/pthread_join.cpp
index d61a096..4d852cb 100644
--- a/libc/bionic/pthread_join.cpp
+++ b/libc/bionic/pthread_join.cpp
@@ -36,7 +36,10 @@
     return EDEADLK;
   }
 
-  pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(t);
+  pthread_internal_t* thread = __pthread_internal_find(t);
+  if (thread == NULL) {
+    return ESRCH;
+  }
 
   ThreadJoinState old_state = THREAD_NOT_JOINED;
   while ((old_state == THREAD_NOT_JOINED || old_state == THREAD_EXITED_NOT_JOINED) &&
@@ -62,6 +65,6 @@
     *return_value = thread->return_value;
   }
 
-  __free_thread(thread);
+  __pthread_internal_remove_and_free(thread);
   return 0;
 }
diff --git a/libc/bionic/pthread_kill.cpp b/libc/bionic/pthread_kill.cpp
index 1ea744f..72a6ed1 100644
--- a/libc/bionic/pthread_kill.cpp
+++ b/libc/bionic/pthread_kill.cpp
@@ -35,6 +35,10 @@
 int pthread_kill(pthread_t t, int sig) {
   ErrnoRestorer errno_restorer;
 
-  pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(t);
+  pthread_internal_t* thread = __pthread_internal_find(t);
+  if (thread == NULL) {
+    return ESRCH;
+  }
+
   return (tgkill(getpid(), thread->tid, sig) == -1) ? errno : 0;
 }
diff --git a/libc/bionic/pthread_setname_np.cpp b/libc/bionic/pthread_setname_np.cpp
index 669ef04..6d2880e 100644
--- a/libc/bionic/pthread_setname_np.cpp
+++ b/libc/bionic/pthread_setname_np.cpp
@@ -43,7 +43,12 @@
 #define MAX_TASK_COMM_LEN 16
 
 static int __open_task_comm_fd(pthread_t t, int flags) {
-  pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(t);
+  pthread_internal_t* thread = __pthread_internal_find(t);
+  if (thread == nullptr) {
+    errno = ENOENT;
+    return -1;
+  }
+
   char comm_name[64];
   snprintf(comm_name, sizeof(comm_name), "/proc/self/task/%d/comm", thread->tid);
   return open(comm_name, O_CLOEXEC | flags);
diff --git a/libc/bionic/pthread_setschedparam.cpp b/libc/bionic/pthread_setschedparam.cpp
index 904baee..0ad68bb 100644
--- a/libc/bionic/pthread_setschedparam.cpp
+++ b/libc/bionic/pthread_setschedparam.cpp
@@ -34,7 +34,10 @@
 int pthread_setschedparam(pthread_t t, int policy, const sched_param* param) {
   ErrnoRestorer errno_restorer;
 
-  pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(t);
+  pthread_internal_t* thread = __pthread_internal_find(t);
+  if (thread == NULL) {
+    return ESRCH;
+  }
 
   int rc = sched_setscheduler(thread->tid, policy, param);
   if (rc == -1) {
diff --git a/libc/include/math.h b/libc/include/math.h
index d9896fc..8bf6fb5 100644
--- a/libc/include/math.h
+++ b/libc/include/math.h
@@ -144,8 +144,6 @@
 double	fma(double, double, double);
 double	hypot(double, double);
 int	ilogb(double) __attribute_const__;
-int(isinf)(double) __attribute_const__ __INTRODUCED_IN(21);
-int	(isnan)(double) __attribute_const__;
 double	lgamma(double);
 long long llrint(double);
 long long llround(double);
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 79c3ac5..b8dd216 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -462,13 +462,13 @@
   if (ref_count_++ == 0) {
     protect_data(PROT_READ | PROT_WRITE);
   }
-}
 
-ProtectedDataGuard::~ProtectedDataGuard() {
   if (ref_count_ == 0) { // overflow
     __libc_fatal("Too many nested calls to dlopen()");
   }
+}
 
+ProtectedDataGuard::~ProtectedDataGuard() {
   if (--ref_count_ == 0) {
     protect_data(PROT_READ);
   }
diff --git a/linker/linker_main.cpp b/linker/linker_main.cpp
index 9ed7505..7634465 100644
--- a/linker/linker_main.cpp
+++ b/linker/linker_main.cpp
@@ -321,7 +321,7 @@
                      "\"%s\": error: Android 5.0 and later only support "
                      "position-independent executables (-fPIE).\n",
                      g_argv[0]);
-    exit(0);
+    exit(EXIT_FAILURE);
   }
 
   // Use LD_LIBRARY_PATH and LD_PRELOAD (but only if we aren't setuid/setgid).
diff --git a/tests/pthread_test.cpp b/tests/pthread_test.cpp
index e0350f2..b0c95fe 100755
--- a/tests/pthread_test.cpp
+++ b/tests/pthread_test.cpp
@@ -235,6 +235,11 @@
   ASSERT_EQ(is_detached, (detach_state == PTHREAD_CREATE_DETACHED));
 }
 
+static void MakeDeadThread(pthread_t& t) {
+  ASSERT_EQ(0, pthread_create(&t, NULL, IdFn, NULL));
+  ASSERT_EQ(0, pthread_join(t, NULL));
+}
+
 TEST(pthread, pthread_create) {
   void* expected_result = reinterpret_cast<void*>(123);
   // Can we create a thread?
@@ -438,6 +443,16 @@
   ASSERT_EQ(0, pthread_join(t, nullptr));
 }
 
+TEST(pthread, pthread_setname_np__pthread_getname_np__no_such_thread) {
+  pthread_t dead_thread;
+  MakeDeadThread(dead_thread);
+
+  // Call pthread_getname_np and pthread_setname_np after the thread has already exited.
+  ASSERT_EQ(ENOENT, pthread_setname_np(dead_thread, "short 3"));
+  char name[64];
+  ASSERT_EQ(ENOENT, pthread_getname_np(dead_thread, name, sizeof(name)));
+}
+
 TEST(pthread, pthread_kill__0) {
   // Signal 0 just tests that the thread exists, so it's safe to call on ourselves.
   ASSERT_EQ(0, pthread_kill(pthread_self(), 0));
@@ -461,6 +476,13 @@
   ASSERT_EQ(0, pthread_kill(pthread_self(), SIGALRM));
 }
 
+TEST(pthread, pthread_detach__no_such_thread) {
+  pthread_t dead_thread;
+  MakeDeadThread(dead_thread);
+
+  ASSERT_EQ(ESRCH, pthread_detach(dead_thread));
+}
+
 TEST(pthread, pthread_getcpuclockid__clock_gettime) {
   SpinFunctionHelper spin_helper;
 
@@ -475,6 +497,46 @@
   ASSERT_EQ(0, pthread_join(t, nullptr));
 }
 
+TEST(pthread, pthread_getcpuclockid__no_such_thread) {
+  pthread_t dead_thread;
+  MakeDeadThread(dead_thread);
+
+  clockid_t c;
+  ASSERT_EQ(ESRCH, pthread_getcpuclockid(dead_thread, &c));
+}
+
+TEST(pthread, pthread_getschedparam__no_such_thread) {
+  pthread_t dead_thread;
+  MakeDeadThread(dead_thread);
+
+  int policy;
+  sched_param param;
+  ASSERT_EQ(ESRCH, pthread_getschedparam(dead_thread, &policy, &param));
+}
+
+TEST(pthread, pthread_setschedparam__no_such_thread) {
+  pthread_t dead_thread;
+  MakeDeadThread(dead_thread);
+
+  int policy = 0;
+  sched_param param;
+  ASSERT_EQ(ESRCH, pthread_setschedparam(dead_thread, policy, &param));
+}
+
+TEST(pthread, pthread_join__no_such_thread) {
+  pthread_t dead_thread;
+  MakeDeadThread(dead_thread);
+
+  ASSERT_EQ(ESRCH, pthread_join(dead_thread, NULL));
+}
+
+TEST(pthread, pthread_kill__no_such_thread) {
+  pthread_t dead_thread;
+  MakeDeadThread(dead_thread);
+
+  ASSERT_EQ(ESRCH, pthread_kill(dead_thread, 0));
+}
+
 TEST(pthread, pthread_join__multijoin) {
   SpinFunctionHelper spin_helper;
 
diff --git a/tests/time_test.cpp b/tests/time_test.cpp
index 4e3fa83..8c4a8a9 100644
--- a/tests/time_test.cpp
+++ b/tests/time_test.cpp
@@ -509,14 +509,14 @@
 
 struct TimerDeleteData {
   timer_t timer_id;
-  pid_t tid;
+  pthread_t thread_id;
   volatile bool complete;
 };
 
 static void TimerDeleteCallback(sigval_t value) {
   TimerDeleteData* tdd = reinterpret_cast<TimerDeleteData*>(value.sival_ptr);
 
-  tdd->tid = gettid();
+  tdd->thread_id = pthread_self();
   timer_delete(tdd->timer_id);
   tdd->complete = true;
 }
@@ -548,9 +548,8 @@
   // Since bionic timers are implemented by creating a thread to handle the
   // callback, verify that the thread actually completes.
   cur_time = time(NULL);
-  while ((kill(tdd.tid, 0) != -1 || errno != ESRCH) && (time(NULL) - cur_time) < 5);
-  ASSERT_EQ(-1, kill(tdd.tid, 0));
-  ASSERT_EQ(ESRCH, errno);
+  while (pthread_detach(tdd.thread_id) != ESRCH && (time(NULL) - cur_time) < 5);
+  ASSERT_EQ(ESRCH, pthread_detach(tdd.thread_id));
 #endif
 }