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Make locks more reliable

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This change switches most of the core locks to be re-entrant, in order
to reduce the chance of deadlocking code that does, clever things with
asynchronous signal handlers. This change implements it it in pthreads
so we're one step closer to having a standardized threading primitives
This commit is contained in:
Justine Tunney 2022-06-11 01:59:26 -07:00
parent 5ea618f0af
commit c260345e06
35 changed files with 369 additions and 258 deletions
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9
libc/intrin/cxaatexit.c
View file

@ -19,6 +19,7 @@
#include "libc/assert.h"
#include "libc/bits/weaken.h"
#include "libc/calls/strace.internal.h"
#include "libc/intrin/pthread.h"
#include "libc/intrin/spinlock.h"
#include "libc/macros.internal.h"
#include "libc/mem/mem.h"
@ -29,7 +30,7 @@
STATIC_YOINK("__cxa_finalize");
static int __cxa_lock;
static pthread_mutex_t __cxa_lock;
/**
* Adds global destructor.
@ -50,7 +51,7 @@ noasan int __cxa_atexit(void *fp, void *arg, void *pred) {
unsigned i;
struct CxaAtexitBlock *b, *b2;
_Static_assert(ATEXIT_MAX == CHAR_BIT * sizeof(b->mask), "");
_spinlock(&__cxa_lock);
pthread_mutex_lock(&__cxa_lock);
b = __cxa_blocks.p;
if (!b) b = __cxa_blocks.p = &__cxa_blocks.root;
if (!~b->mask) {
@ -59,7 +60,7 @@ noasan int __cxa_atexit(void *fp, void *arg, void *pred) {
b2->next = b;
__cxa_blocks.p = b = b2;
} else {
_spunlock(&__cxa_lock);
pthread_mutex_unlock(&__cxa_lock);
return enomem();
}
}
@ -69,6 +70,6 @@ noasan int __cxa_atexit(void *fp, void *arg, void *pred) {
b->p[i].fp = fp;
b->p[i].arg = arg;
b->p[i].pred = pred;
_spunlock(&__cxa_lock);
pthread_mutex_unlock(&__cxa_lock);
return 0;
}