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Only wipe TLS for user-supplied stacks.

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Bug: 16667988
Change-Id: Id180ab2bc6713e1612386120a306db5bbf1d6046
This commit is contained in:
Elliott Hughes
2014-07-30 14:48:10 -07:00
parent 4ad5066e1d
commit 40a5217448
4 changed files with 74 additions and 19 deletions
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10
libc/bionic/pthread_create.cpp
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@@ -51,9 +51,9 @@ extern "C" int __isthreaded;
// This code is used both by each new pthread and the code that initializes the main thread.
void __init_tls(pthread_internal_t* thread) {
// Zero-initialize all the slots after TLS_SLOT_SELF and TLS_SLOT_THREAD_ID.
for (size_t i = TLS_SLOT_ERRNO; i < BIONIC_TLS_SLOTS; ++i) {
thread->tls[i] = NULL;
if (thread->user_allocated_stack()) {
// We don't know where the user got their stack, so assume the worst and zero the TLS area.
memset(&thread->tls[0], 0, BIONIC_TLS_SLOTS * sizeof(void*));
}
// Slot 0 must point to itself. The x86 Linux kernel reads the TLS from %fs:0.
@@ -66,7 +66,7 @@ void __init_tls(pthread_internal_t* thread) {
void __init_alternate_signal_stack(pthread_internal_t* thread) {
// Create and set an alternate signal stack.
stack_t ss;
ss.ss_sp = mmap(NULL, SIGSTKSZ, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
ss.ss_sp = mmap(NULL, SIGSTKSZ, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
if (ss.ss_sp != MAP_FAILED) {
ss.ss_size = SIGSTKSZ;
ss.ss_flags = 0;
@@ -227,7 +227,7 @@ int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr,
// 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.
pthread_mutex_unlock(&thread->startup_handshake_mutex);
if ((thread->attr.flags & PTHREAD_ATTR_FLAG_USER_ALLOCATED_STACK) == 0) {
if (!thread->user_allocated_stack()) {
munmap(thread->attr.stack_base, thread->attr.stack_size);
}
free(thread);