diff --git a/libc/bionic/malloc_common.cpp b/libc/bionic/malloc_common.cpp
index ed5537f..6b7006d 100644
--- a/libc/bionic/malloc_common.cpp
+++ b/libc/bionic/malloc_common.cpp
@@ -46,6 +46,7 @@
 #include "malloc_common.h"
 #include "malloc_limit.h"
 #include "malloc_tagged_pointers.h"
+#include "memory_mitigation_state.h"
 
 // =============================================================================
 // Global variables instantations.
@@ -326,6 +327,9 @@
       return MaybeInitGwpAsan(globals, *reinterpret_cast<bool*>(arg));
     });
   }
+  if (opcode == M_DISABLE_MEMORY_MITIGATIONS) {
+    return DisableMemoryMitigations(arg, arg_size);
+  }
   errno = ENOTSUP;
   return false;
 }
diff --git a/libc/bionic/malloc_common_dynamic.cpp b/libc/bionic/malloc_common_dynamic.cpp
index 6a82ae3..eeeaff9 100644
--- a/libc/bionic/malloc_common_dynamic.cpp
+++ b/libc/bionic/malloc_common_dynamic.cpp
@@ -70,6 +70,7 @@
 #include "malloc_common_dynamic.h"
 #include "malloc_heapprofd.h"
 #include "malloc_limit.h"
+#include "memory_mitigation_state.h"
 
 // =============================================================================
 // Global variables instantations.
@@ -533,6 +534,9 @@
       return MaybeInitGwpAsan(globals, *reinterpret_cast<bool*>(arg));
     });
   }
+  if (opcode == M_DISABLE_MEMORY_MITIGATIONS) {
+    return DisableMemoryMitigations(arg, arg_size);
+  }
   // Try heapprofd's mallopt, as it handles options not covered here.
   return HeapprofdMallopt(opcode, arg, arg_size);
 }
diff --git a/libc/bionic/memory_mitigation_state.cpp b/libc/bionic/memory_mitigation_state.cpp
new file mode 100644
index 0000000..82b0b7b
--- /dev/null
+++ b/libc/bionic/memory_mitigation_state.cpp
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2020 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 "memory_mitigation_state.h"
+
+#include <dirent.h>
+#include <pthread.h>
+#include <semaphore.h>
+#include <stdatomic.h>
+#include <stdlib.h>
+#include <sys/prctl.h>
+#include <sys/types.h>
+
+#include <bionic/mte.h>
+#include <bionic/reserved_signals.h>
+
+#include "private/ScopedRWLock.h"
+#include "pthread_internal.h"
+
+extern "C" void scudo_malloc_set_zero_contents(int zero_contents);
+extern "C" void scudo_malloc_disable_memory_tagging();
+
+#ifdef ANDROID_EXPERIMENTAL_MTE
+static bool set_tcf_on_all_threads(int tcf) {
+  static int g_tcf;
+  g_tcf = tcf;
+
+  return android_run_on_all_threads(
+      [](void*) {
+        int tagged_addr_ctrl = prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0);
+        if (tagged_addr_ctrl < 0) {
+          return false;
+        }
+
+        tagged_addr_ctrl = (tagged_addr_ctrl & ~PR_MTE_TCF_MASK) | g_tcf;
+        if (prctl(PR_SET_TAGGED_ADDR_CTRL, tagged_addr_ctrl, 0, 0, 0) < 0) {
+          return false;
+        }
+        return true;
+      },
+      nullptr);
+}
+#endif
+
+bool DisableMemoryMitigations(void* arg, size_t arg_size) {
+  if (arg || arg_size) {
+    return false;
+  }
+
+#ifdef USE_SCUDO
+  scudo_malloc_set_zero_contents(0);
+
+#ifdef ANDROID_EXPERIMENTAL_MTE
+  if (mte_supported() && set_tcf_on_all_threads(PR_MTE_TCF_NONE)) {
+    scudo_malloc_disable_memory_tagging();
+  }
+#endif
+#endif
+
+  return true;
+}
diff --git a/libc/bionic/memory_mitigation_state.h b/libc/bionic/memory_mitigation_state.h
new file mode 100644
index 0000000..ffa1912
--- /dev/null
+++ b/libc/bionic/memory_mitigation_state.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2020 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.
+ */
+
+#pragma once
+
+#include <stddef.h>
+
+bool DisableMemoryMitigations(void* arg, size_t arg_size);
diff --git a/libc/bionic/pthread_create.cpp b/libc/bionic/pthread_create.cpp
index c528105..206d5fd 100644
--- a/libc/bionic/pthread_create.cpp
+++ b/libc/bionic/pthread_create.cpp
@@ -39,6 +39,7 @@
 
 #include <async_safe/log.h>
 
+#include "private/ScopedRWLock.h"
 #include "private/bionic_constants.h"
 #include "private/bionic_defs.h"
 #include "private/bionic_globals.h"
@@ -357,6 +358,7 @@
   return nullptr;
 }
 
+pthread_rwlock_t g_thread_creation_lock = PTHREAD_RWLOCK_INITIALIZER;
 
 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
 int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr,
@@ -406,6 +408,8 @@
   tls = &tls_descriptor;
 #endif
 
+  ScopedReadLock locker(&g_thread_creation_lock);
+
   sigset64_t block_all_mask;
   sigfillset64(&block_all_mask);
   __rt_sigprocmask(SIG_SETMASK, &block_all_mask, &thread->start_mask, sizeof(thread->start_mask));
diff --git a/libc/bionic/pthread_exit.cpp b/libc/bionic/pthread_exit.cpp
index 81dab57..bde95ec 100644
--- a/libc/bionic/pthread_exit.cpp
+++ b/libc/bionic/pthread_exit.cpp
@@ -35,6 +35,7 @@
 
 #include "private/bionic_constants.h"
 #include "private/bionic_defs.h"
+#include "private/ScopedRWLock.h"
 #include "private/ScopedSignalBlocker.h"
 #include "pthread_internal.h"
 
@@ -103,9 +104,18 @@
          !atomic_compare_exchange_weak(&thread->join_state, &old_state, THREAD_EXITED_NOT_JOINED)) {
   }
 
-  // We don't want to take a signal after unmapping the stack, the shadow call
-  // stack, or dynamic TLS memory.
-  ScopedSignalBlocker ssb;
+  // android_run_on_all_threads() needs to see signals blocked atomically with setting the
+  // terminating flag, so take the creation lock while doing these operations.
+  {
+    ScopedReadLock locker(&g_thread_creation_lock);
+    atomic_store(&thread->terminating, true);
+
+    // We don't want to take a signal after unmapping the stack, the shadow call stack, or dynamic
+    // TLS memory.
+    sigset64_t set;
+    sigfillset64(&set);
+    __rt_sigprocmask(SIG_BLOCK, &set, nullptr, sizeof(sigset64_t));
+  }
 
 #ifdef __aarch64__
   // Free the shadow call stack and guard pages.
diff --git a/libc/bionic/pthread_internal.cpp b/libc/bionic/pthread_internal.cpp
index e091158..6a7ee2f 100644
--- a/libc/bionic/pthread_internal.cpp
+++ b/libc/bionic/pthread_internal.cpp
@@ -29,12 +29,15 @@
 #include "pthread_internal.h"
 
 #include <errno.h>
+#include <semaphore.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/mman.h>
 
 #include <async_safe/log.h>
+#include <bionic/reserved_signals.h>
 
+#include "private/ErrnoRestorer.h"
 #include "private/ScopedRWLock.h"
 #include "private/bionic_futex.h"
 #include "private/bionic_tls.h"
@@ -115,3 +118,76 @@
   }
   return nullptr;
 }
+
+bool android_run_on_all_threads(bool (*func)(void*), void* arg) {
+  // Take the locks in this order to avoid inversion (pthread_create ->
+  // __pthread_internal_add).
+  ScopedWriteLock creation_locker(&g_thread_creation_lock);
+  ScopedReadLock list_locker(&g_thread_list_lock);
+
+  // Call the function directly for the current thread so that we don't need to worry about
+  // the consequences of synchronizing with ourselves.
+  if (!func(arg)) {
+    return false;
+  }
+
+  static sem_t g_sem;
+  if (sem_init(&g_sem, 0, 0) != 0) {
+    return false;
+  }
+
+  static bool (*g_func)(void*);
+  static void *g_arg;
+  g_func = func;
+  g_arg = arg;
+
+  static _Atomic(bool) g_retval;
+  atomic_init(&g_retval, true);
+
+  auto handler = [](int, siginfo_t*, void*) {
+    ErrnoRestorer restorer;
+    if (!g_func(g_arg)) {
+      atomic_store(&g_retval, false);
+    }
+    sem_post(&g_sem);
+  };
+
+  struct sigaction act = {}, oldact;
+  act.sa_flags = SA_SIGINFO;
+  act.sa_sigaction = handler;
+  sigfillset(&act.sa_mask);
+  if (sigaction(BIONIC_SIGNAL_RUN_ON_ALL_THREADS, &act, &oldact) != 0) {
+    sem_destroy(&g_sem);
+    return false;
+  }
+
+  pid_t my_pid = getpid();
+  size_t num_tids = 0;
+  for (pthread_internal_t* t = g_thread_list; t != nullptr; t = t->next) {
+    // The function is called directly for the current thread above, so no need to send a signal to
+    // ourselves to call it here.
+    if (t == __get_thread()) continue;
+
+    // If a thread is terminating (has blocked signals) or has already terminated, our signal will
+    // never be received, so we need to check for that condition and skip the thread if it is the
+    // case.
+    if (atomic_load(&t->terminating)) continue;
+
+    if (tgkill(my_pid, t->tid, BIONIC_SIGNAL_RUN_ON_ALL_THREADS) == 0) {
+      ++num_tids;
+    } else {
+      atomic_store(&g_retval, false);
+    }
+  }
+
+  for (size_t i = 0; i != num_tids; ++i) {
+    if (TEMP_FAILURE_RETRY(sem_wait(&g_sem)) != 0) {
+      atomic_store(&g_retval, false);
+      break;
+    }
+  }
+
+  sigaction(BIONIC_SIGNAL_RUN_ON_ALL_THREADS, &oldact, 0);
+  sem_destroy(&g_sem);
+  return atomic_load(&g_retval);
+}
diff --git a/libc/bionic/pthread_internal.h b/libc/bionic/pthread_internal.h
index 1f055f5..071a5bc 100644
--- a/libc/bionic/pthread_internal.h
+++ b/libc/bionic/pthread_internal.h
@@ -132,6 +132,11 @@
   // top of the stack quickly, which would otherwise require special logic for the main thread.
   uintptr_t stack_top;
 
+  // Whether the thread is in the process of terminating (has blocked signals), or has already
+  // terminated. This is used by android_run_on_all_threads() to avoid sending a signal to a thread
+  // that will never receive it.
+  _Atomic(bool) terminating;
+
   Lock startup_handshake_lock;
 
   void* mmap_base;
@@ -242,3 +247,7 @@
 __LIBC_HIDDEN__ extern void __bionic_atfork_run_prepare();
 __LIBC_HIDDEN__ extern void __bionic_atfork_run_child();
 __LIBC_HIDDEN__ extern void __bionic_atfork_run_parent();
+
+extern "C" bool android_run_on_all_threads(bool (*func)(void*), void* arg);
+
+extern pthread_rwlock_t g_thread_creation_lock;