--- old/src/hotspot/os/linux/os_linux.cpp 2019-06-28 14:09:30.151067412 -0700 +++ new/src/hotspot/os/linux/os_linux.cpp 2019-06-28 14:09:29.779062295 -0700 @@ -800,6 +800,71 @@ return 0; } +// On Linux, glibc places static TLS blocks (for __thread variables) on +// the thread stack. This decreases the stack size actually available +// to threads. +// +// For large static TLS sizes, this may cause threads to malfunction due +// to insufficient stack space. This is a well-known issue in glibc: +// http://sourceware.org/bugzilla/show_bug.cgi?id=11787. +// +// As a workaround, we call a private but assumed-stable glibc function, +// __pthread_get_minstack() to obtain the minstack size and derive the +// static TLS size from it. We then increase the user requested stack +// size by this TLS size. +// +// Due to compatibility concerns, this size adjustment is opt-in and +// controlled via AdjustStackSizeForTLS. +typedef size_t (*GetMinStack)(const pthread_attr_t *attr); + +GetMinStack _get_minstack_func = NULL; + +static void get_minstack_init() { + _get_minstack_func = + (GetMinStack)dlsym(RTLD_DEFAULT, "__pthread_get_minstack"); + log_info(os, thread)("Lookup of __pthread_get_minstack %s", + _get_minstack_func == NULL ? "failed" : "succeeded"); +} + +// Returns the size of the static TLS area glibc puts on thread stacks. +static size_t get_static_tls_area_size(const pthread_attr_t *attr) { + size_t tls_size = 0; + if (_get_minstack_func != NULL) { + // Obtain the pthread minstack size by calling __pthread_get_minstack. + size_t minstack_size = _get_minstack_func(attr); + + // Remove non-TLS area size included in minstack size returned + // by __pthread_get_minstack() to get the static TLS size. + // In glibc before 2.27, minstack size includes guard_size. + // In glibc 2.27 and later, guard_size is automatically added + // to the stack size by pthread_create and is no longer included + // in minstack size. In both cases, the guard_size is taken into + // account, so there is no need to adjust the result for that. + // + // Although __pthread_get_minstack() is a private glibc function, + // it is expected to have a stable behavior across future glibc + // versions while glibc still allocats the static TLS blocks off + // the stack. Following is glibc 2.28 __pthread_get_minstack(): + // + // size_t + // __pthread_get_minstack (const pthread_attr_t *attr) + // { + // return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN; + // } + // + // + // The following 'minstack_size > os::vm_page_size() + PTHREAD_STACK_MIN' + // if check is done for precaution. + if (minstack_size > (size_t)os::vm_page_size() + PTHREAD_STACK_MIN) { + tls_size = minstack_size - os::vm_page_size() - PTHREAD_STACK_MIN; + } + } + + log_info(os, thread)("Stack size adjustment for TLS is " SIZE_FORMAT, + tls_size); + return tls_size; +} + bool os::create_thread(Thread* thread, ThreadType thr_type, size_t req_stack_size) { assert(thread->osthread() == NULL, "caller responsible"); @@ -825,7 +890,7 @@ // Calculate stack size if it's not specified by caller. size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size); - // In the Linux NPTL pthread implementation the guard size mechanism + // In glibc versions prior to 2.7 the guard size mechanism // is not implemented properly. The posix standard requires adding // the size of the guard pages to the stack size, instead Linux // takes the space out of 'stacksize'. Thus we adapt the requested @@ -833,17 +898,27 @@ // behaviour. However, be careful not to end up with a size // of zero due to overflow. Don't add the guard page in that case. size_t guard_size = os::Linux::default_guard_size(thr_type); - if (stack_size <= SIZE_MAX - guard_size) { - stack_size += guard_size; + // Configure glibc guard page. Must happen before calling + // get_static_tls_area_size(), which uses the guard_size. + pthread_attr_setguardsize(&attr, guard_size); + + size_t stack_adjust_size = 0; + if (AdjustStackSizeForTLS) { + // Adjust the stack_size for on-stack TLS - see get_static_tls_area_size(). + stack_adjust_size += get_static_tls_area_size(&attr); + } else { + stack_adjust_size += guard_size; + } + + stack_adjust_size = align_up(stack_adjust_size, os::vm_page_size()); + if (stack_size <= SIZE_MAX - stack_adjust_size) { + stack_size += stack_adjust_size; } assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned"); int status = pthread_attr_setstacksize(&attr, stack_size); assert_status(status == 0, status, "pthread_attr_setstacksize"); - // Configure glibc guard page. - pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); - ThreadState state; { @@ -5122,6 +5197,10 @@ jdk_misc_signal_init(); } + if (AdjustStackSizeForTLS) { + get_minstack_init(); + } + // Check and sets minimum stack sizes against command line options if (Posix::set_minimum_stack_sizes() == JNI_ERR) { return JNI_ERR;