From d0ba09837bc033e236e921304b213daea0fe2653 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Fri, 26 Apr 2013 16:16:04 -0400 Subject: [PATCH] make last thread's pthread_exit give exit(0) a consistent state the previous few commits ended up leaving the thread count and signal mask wrong for atexit handlers and stdio cleanup. --- src/thread/pthread_create.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c index 0567f966..5d5d3a6f 100644 --- a/src/thread/pthread_create.c +++ b/src/thread/pthread_create.c @@ -12,6 +12,7 @@ weak_alias(dummy_0, __pthread_tsd_run_dtors); _Noreturn void pthread_exit(void *result) { pthread_t self = pthread_self(); + sigset_t set; self->result = result; @@ -35,9 +36,18 @@ _Noreturn void pthread_exit(void *result) * This is important to ensure that dynamically allocated TLS * is not under-allocated/over-committed, and possibly for other * reasons as well. */ - __syscall(SYS_rt_sigprocmask, SIG_BLOCK, SIGALL_SET, 0, _NSIG/8); - - if (a_fetch_add(&libc.threads_minus_1, -1)==0) exit(0); + __syscall(SYS_rt_sigprocmask, SIG_BLOCK, SIGALL_SET, &set, _NSIG/8); + + /* It's impossible to determine whether this is "the last thread" + * until performing the atomic decrement, since multiple threads + * could exit at the same time. For the last thread, revert the + * decrement and unblock signals to give the atexit handlers and + * stdio cleanup code a consistent state. */ + if (a_fetch_add(&libc.threads_minus_1, -1)==0) { + libc.threads_minus_1 = 0; + __syscall(SYS_rt_sigprocmask, SIG_SETMASK, &set, 0, _NSIG/8); + exit(0); + } if (self->detached && self->map_base) { /* Detached threads must avoid the kernel clear_child_tid -- 2.25.1