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Make detached threads work better

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This change adds a double linked list of threads, so that pthread_exit()
will know when it should call exit() from an orphaned child. This change
also improves ftrace and strace logging.
This commit is contained in:
Justine Tunney 2022-11-09 03:58:57 -08:00
parent b74d8c1acd
commit cee6871710
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GPG key ID: BE714B4575D6E328
37 changed files with 638 additions and 314 deletions
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35
libc/thread/pthread_create.c
View file

@ -39,7 +39,9 @@
#include "libc/thread/posixthread.internal.h"
#include "libc/thread/spawn.h"
#include "libc/thread/thread.h"
#include "libc/thread/tls.h"
#include "libc/thread/wait0.internal.h"
#include "third_party/nsync/dll.h"
STATIC_YOINK("nsync_mu_lock");
STATIC_YOINK("nsync_mu_unlock");
@ -48,19 +50,13 @@ STATIC_YOINK("_pthread_atfork");
#define MAP_ANON_OPENBSD 0x1000
#define MAP_STACK_OPENBSD 0x4000
errno_t _pthread_wait(struct PosixThread *pt) {
return _wait0(&pt->tib->tib_tid);
}
void _pthread_free(struct PosixThread *pt) {
if (pt->flags & PT_MAINTHREAD) return;
if (pt->flags & PT_STATIC) return;
free(pt->tls);
if ((pt->flags & PT_OWNSTACK) && //
pt->attr.__stackaddr && //
pt->attr.__stackaddr != MAP_FAILED) {
if (munmap(pt->attr.__stackaddr, pt->attr.__stacksize)) {
notpossible;
}
_npassert(!munmap(pt->attr.__stackaddr, pt->attr.__stacksize));
}
if (pt->altstack) {
free(pt->altstack);
@ -69,9 +65,11 @@ void _pthread_free(struct PosixThread *pt) {
}
static int PosixThread(void *arg, int tid) {
void *rc;
struct sigaltstack ss;
struct PosixThread *pt = arg;
enum PosixThreadStatus status;
struct sigaltstack ss;
_unassert(__get_tls()->tib_tid > 0);
if (pt->altstack) {
ss.ss_flags = 0;
ss.ss_size = SIGSTKSZ;
@ -87,12 +85,12 @@ static int PosixThread(void *arg, int tid) {
if (!setjmp(pt->exiter)) {
__get_tls()->tib_pthread = (pthread_t)pt;
_sigsetmask(pt->sigmask);
pt->rc = pt->start(pt->arg);
rc = pt->start(pt->arg);
// ensure pthread_cleanup_pop(), and pthread_exit() popped cleanup
_npassert(!pt->cleanup);
// calling pthread_exit() will either jump back here, or call exit
pthread_exit(rc);
}
// run garbage collector, call key destructors, and set change state
_pthread_cleanup(pt);
// return to clone polyfill which clears tid, wakes futex, and exits
return 0;
}
@ -234,13 +232,19 @@ static errno_t pthread_create_impl(pthread_t *thread,
case PTHREAD_CREATE_DETACHED:
atomic_store_explicit(&pt->status, kPosixThreadDetached,
memory_order_relaxed);
_pthread_zombies_add(pt);
break;
default:
_pthread_free(pt);
return EINVAL;
}
// add thread to global list
// we add it to the end since zombies go at the beginning
nsync_dll_init_(&pt->list, pt);
pthread_spin_lock(&_pthread_lock);
_pthread_list = nsync_dll_make_last_in_list_(_pthread_list, &pt->list);
pthread_spin_unlock(&_pthread_lock);
// launch PosixThread(pt) in new thread
pt->sigmask = oldsigs;
if ((rc = clone(PosixThread, pt->attr.__stackaddr,
@ -249,6 +253,9 @@ static errno_t pthread_create_impl(pthread_t *thread,
CLONE_SIGHAND | CLONE_SETTLS | CLONE_PARENT_SETTID |
CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID,
pt, &pt->ptid, pt->tib, &pt->tib->tib_tid))) {
pthread_spin_lock(&_pthread_lock);
_pthread_list = nsync_dll_remove_(_pthread_list, &pt->list);
pthread_spin_unlock(&_pthread_lock);
_pthread_free(pt);
return rc;
}
@ -313,7 +320,7 @@ errno_t pthread_create(pthread_t *thread, const pthread_attr_t *attr,
void *(*start_routine)(void *), void *arg) {
errno_t rc;
__require_tls();
_pthread_zombies_decimate();
pthread_decimate_np();
BLOCK_SIGNALS;
rc = pthread_create_impl(thread, attr, start_routine, arg, _SigMask);
ALLOW_SIGNALS;