linux-user/syscall: extend lock around cpu-list
There is a potential race if several threads exit at once. To serialise
the exits extend the lock above the initial checking of the CPU list.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20160930213106.20186-11-alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 0815f30..fa559be 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -7476,13 +7476,16 @@
break;
}
+ cpu_list_lock();
+
if (CPU_NEXT(first_cpu)) {
TaskState *ts;
- cpu_list_lock();
/* Remove the CPU from the list. */
QTAILQ_REMOVE(&cpus, cpu, node);
+
cpu_list_unlock();
+
ts = cpu->opaque;
if (ts->child_tidptr) {
put_user_u32(0, ts->child_tidptr);
@@ -7495,6 +7498,8 @@
rcu_unregister_thread();
pthread_exit(NULL);
}
+
+ cpu_list_unlock();
#ifdef TARGET_GPROF
_mcleanup();
#endif