1 files changed, 17 insertions, 5 deletions

diff --git a/libc/bionic/pthread_create.cpp b/libc/bionic/pthread_create.cpp
index ff972c3ec..7a266501d 100644
--- a/libc/bionic/pthread_create.cpp
+++ b/libc/bionic/pthread_create.cpp
@@ -50,7 +50,7 @@ void __init_user_desc(struct user_desc*, bool, void*);
 #endif
 
 // This code is used both by each new pthread and the code that initializes the main thread.
-void __init_tls(pthread_internal_t* thread) {
+bool __init_tls(pthread_internal_t* thread) {
   // Slot 0 must point to itself. The x86 Linux kernel reads the TLS from %fs:0.
   thread->tls[TLS_SLOT_SELF] = thread->tls;
   thread->tls[TLS_SLOT_THREAD_ID] = thread;
@@ -59,15 +59,24 @@ void __init_tls(pthread_internal_t* thread) {
   size_t allocation_size = BIONIC_TLS_SIZE + 2 * PAGE_SIZE;
   void* allocation = mmap(nullptr, allocation_size, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
   if (allocation == MAP_FAILED) {
-    async_safe_fatal("failed to allocate TLS: %s", strerror(errno));
+    async_safe_format_log(ANDROID_LOG_WARN, "libc",
+                          "pthread_create failed: couldn't allocate TLS: %s", strerror(errno));
+    return false;
   }
-  prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, allocation, allocation_size, "bionic TLS guard page");
 
+  prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, allocation, allocation_size, "bionic TLS guard");
+
+  // Carve out the writable TLS section.
   thread->bionic_tls = reinterpret_cast<bionic_tls*>(static_cast<char*>(allocation) + PAGE_SIZE);
   if (mprotect(thread->bionic_tls, BIONIC_TLS_SIZE, PROT_READ | PROT_WRITE) != 0) {
-    async_safe_fatal("failed to mprotect TLS: %s", strerror(errno));
+    async_safe_format_log(ANDROID_LOG_WARN, "libc",
+                          "pthread_create failed: couldn't mprotect TLS: %s", strerror(errno));
+    munmap(allocation, allocation_size);
+    return false;
   }
+
   prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, thread->bionic_tls, BIONIC_TLS_SIZE, "bionic TLS");
+  return true;
 }
 
 void __init_thread_stack_guard(pthread_internal_t* thread) {
@@ -192,7 +201,10 @@ static int __allocate_thread(pthread_attr_t* attr, pthread_internal_t** threadp,
 
   thread->mmap_size = mmap_size;
   thread->attr = *attr;
-  __init_tls(thread);
+  if (!__init_tls(thread)) {
+    if (thread->mmap_size != 0) munmap(thread->attr.stack_base, thread->mmap_size);
+    return EAGAIN;
+  }
   __init_thread_stack_guard(thread);
 
   *threadp = thread;