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fix pthread_detach inadvertently acting as cancellation point in race case
[musl]
/
src
/
thread
/
pthread_cancel.c
diff --git
a/src/thread/pthread_cancel.c
b/src/thread/pthread_cancel.c
index
f17ce88
..
139a6fc
100644
(file)
--- a/
src/thread/pthread_cancel.c
+++ b/
src/thread/pthread_cancel.c
@@
-1,12
+1,17
@@
+#define _GNU_SOURCE
+#include <string.h>
#include "pthread_impl.h"
#include "syscall.h"
#include "pthread_impl.h"
#include "syscall.h"
-void __cancel()
+hidden long __cancel(), __syscall_cp_asm(), __syscall_cp_c();
+
+long __cancel()
{
pthread_t self = __pthread_self();
{
pthread_t self = __pthread_self();
- self->canceldisable = 1;
- self->cancelasync = 0;
- pthread_exit(PTHREAD_CANCELED);
+ if (self->canceldisable == PTHREAD_CANCEL_ENABLE || self->cancelasync)
+ pthread_exit(PTHREAD_CANCELED);
+ self->canceldisable = PTHREAD_CANCEL_DISABLE;
+ return -ECANCELED;
}
long __syscall_cp_asm(volatile void *, syscall_arg_t,
}
long __syscall_cp_asm(volatile void *, syscall_arg_t,
@@
-19,13
+24,16
@@
long __syscall_cp_c(syscall_arg_t nr,
{
pthread_t self;
long r;
{
pthread_t self;
long r;
+ int st;
- if (!libc.has_thread_pointer || (self = __pthread_self())->canceldisable)
+ if ((st=(self=__pthread_self())->canceldisable)
+ && (st==PTHREAD_CANCEL_DISABLE || nr==SYS_close))
return __syscall(nr, u, v, w, x, y, z);
r = __syscall_cp_asm(&self->cancel, nr, u, v, w, x, y, z);
return __syscall(nr, u, v, w, x, y, z);
r = __syscall_cp_asm(&self->cancel, nr, u, v, w, x, y, z);
- if (r==-EINTR && nr!=SYS_close && self->cancel && !self->canceldisable)
- __cancel();
+ if (r==-EINTR && nr!=SYS_close && self->cancel &&
+ self->canceldisable != PTHREAD_CANCEL_DISABLE)
+ r = __cancel();
return r;
}
return r;
}
@@
-35,30
+43,37
@@
static void _sigaddset(sigset_t *set, int sig)
set->__bits[s/8/sizeof *set->__bits] |= 1UL<<(s&8*sizeof *set->__bits-1);
}
set->__bits[s/8/sizeof *set->__bits] |= 1UL<<(s&8*sizeof *set->__bits-1);
}
+extern hidden const char __cp_begin[1], __cp_end[1], __cp_cancel[1];
+
static void cancel_handler(int sig, siginfo_t *si, void *ctx)
{
pthread_t self = __pthread_self();
ucontext_t *uc = ctx;
static void cancel_handler(int sig, siginfo_t *si, void *ctx)
{
pthread_t self = __pthread_self();
ucontext_t *uc = ctx;
- const char *ip = ((char **)&uc->uc_mcontext)[CANCEL_REG_IP];
- extern const char __cp_begin[1], __cp_end[1];
+ uintptr_t pc = uc->uc_mcontext.MC_PC;
a_barrier();
a_barrier();
- if (!self->cancel || self->canceldisable) return;
+ if (!self->cancel || self->canceldisable
== PTHREAD_CANCEL_DISABLE
) return;
_sigaddset(&uc->uc_sigmask, SIGCANCEL);
_sigaddset(&uc->uc_sigmask, SIGCANCEL);
- if (self->cancelasync || ip >= __cp_begin && ip < __cp_end) {
- self->canceldisable = 1;
+ if (self->cancelasync) {
pthread_sigmask(SIG_SETMASK, &uc->uc_sigmask, 0);
__cancel();
}
pthread_sigmask(SIG_SETMASK, &uc->uc_sigmask, 0);
__cancel();
}
+ if (pc >= (uintptr_t)__cp_begin && pc < (uintptr_t)__cp_end) {
+ uc->uc_mcontext.MC_PC = (uintptr_t)__cp_cancel;
+#ifdef CANCEL_GOT
+ uc->uc_mcontext.MC_GOT = CANCEL_GOT;
+#endif
+ return;
+ }
+
__syscall(SYS_tkill, self->tid, SIGCANCEL);
}
void __testcancel()
{
__syscall(SYS_tkill, self->tid, SIGCANCEL);
}
void __testcancel()
{
- if (!libc.has_thread_pointer) return;
pthread_t self = __pthread_self();
if (self->cancel && !self->canceldisable)
__cancel();
pthread_t self = __pthread_self();
if (self->cancel && !self->canceldisable)
__cancel();
@@
-67,10
+82,10
@@
void __testcancel()
static void init_cancellation()
{
struct sigaction sa = {
static void init_cancellation()
{
struct sigaction sa = {
- .sa_flags = SA_SIGINFO | SA_RESTART,
+ .sa_flags = SA_SIGINFO | SA_RESTART
| SA_ONSTACK
,
.sa_sigaction = cancel_handler
};
.sa_sigaction = cancel_handler
};
-
sigfillset(&sa.sa_mask
);
+
memset(&sa.sa_mask, -1, _NSIG/8
);
__libc_sigaction(SIGCANCEL, &sa, 0);
}
__libc_sigaction(SIGCANCEL, &sa, 0);
}
@@
-82,5
+97,10
@@
int pthread_cancel(pthread_t t)
init = 1;
}
a_store(&t->cancel, 1);
init = 1;
}
a_store(&t->cancel, 1);
+ if (t == pthread_self()) {
+ if (t->canceldisable == PTHREAD_CANCEL_ENABLE && t->cancelasync)
+ pthread_exit(PTHREAD_CANCELED);
+ return 0;
+ }
return pthread_kill(t, SIGCANCEL);
}
return pthread_kill(t, SIGCANCEL);
}