Correct NetBSD support in pthread_once(3)/TSan

[krytarowski]

Summary

The pthread_once(3)/NetBSD type is built with the following structure:

struct __pthread_once_st {
pthread_mutex_t pto_mutex;
int pto_done;
};

Set the pto_done position as shifted by __sanitizer::pthread_mutex_t_sz
from the beginning of the pthread_once struct.

This corrects deadlocks when the pthread_once(3) function
is used.

Sponsored by <The NetBSD Foundation>

[dvyukov]

lib/tsan/rtl/tsan_interceptors.cc

1360

No, Kostya will not approve this.

1364

You said first field is pthread_mutex_t, why is this pthread_t_sz?

[krytarowski]

lib/tsan/rtl/tsan_interceptors.cc

1360

OK, I will change it back to if().

1364

My mistake. I will try to add pthread_mutex_t_sz in sanitizer_platform_limits_netbsd.{cc,h} and reuse it.

[krytarowski]

Correct type of shift: pthread_t_sz -> pthread_mutex_t_sz.
Add new value pthread_mutex_t_sz.
Revert ifdef change to if(){}

[krytarowski]

This version still works. Apparently by an accident the wrong previous one functioned ok.

lib/sanitizer_common/sanitizer_platform_limits_netbsd.h

 
 namespace __sanitizer {
 extern unsigned struct_utsname_sz;
 extern unsigned struct_stat_sz;
 extern unsigned struct_rusage_sz;
 extern unsigned siginfo_t_sz;
 extern unsigned struct_itimerval_sz;
 extern unsigned pthread_t_sz;
+extern unsigned pthread_mutex_t_sz;
 extern unsigned pthread_cond_t_sz;
 extern unsigned pid_t_sz;
 extern unsigned timeval_sz;
 extern unsigned uid_t_sz;
 extern unsigned gid_t_sz;
 extern unsigned mbstate_t_sz;
 extern unsigned struct_timezone_sz;
 extern unsigned struct_tms_sz;

lib/sanitizer_common/sanitizer_platform_limits_netbsd.cc

 unsigned struct_rusage_sz = sizeof(struct rusage);
 unsigned struct_tm_sz = sizeof(struct tm);
 unsigned struct_passwd_sz = sizeof(struct passwd);
 unsigned struct_group_sz = sizeof(struct group);
 unsigned siginfo_t_sz = sizeof(siginfo_t);
 unsigned struct_sigaction_sz = sizeof(struct sigaction);
 unsigned struct_itimerval_sz = sizeof(struct itimerval);
 unsigned pthread_t_sz = sizeof(pthread_t);
+unsigned pthread_mutex_t_sz = sizeof(pthread_mutex_t);
 unsigned pthread_cond_t_sz = sizeof(pthread_cond_t);
 unsigned pid_t_sz = sizeof(pid_t);
 unsigned timeval_sz = sizeof(timeval);
 unsigned uid_t_sz = sizeof(uid_t);
 unsigned gid_t_sz = sizeof(gid_t);
 unsigned mbstate_t_sz = sizeof(mbstate_t);
 unsigned sigset_t_sz = sizeof(sigset_t);
 unsigned struct_timezone_sz = sizeof(struct timezone);

lib/sanitizer_common/sanitizer_platform_limits_posix.h

namespace __sanitizer {
   extern unsigned struct_stat_sz;
 #if !SANITIZER_FREEBSD && !SANITIZER_IOS
   extern unsigned struct_stat64_sz;
 #endif
   extern unsigned struct_rusage_sz;
   extern unsigned siginfo_t_sz;
   extern unsigned struct_itimerval_sz;
   extern unsigned pthread_t_sz;
+  extern unsigned pthread_mutex_t_sz;
   extern unsigned pthread_cond_t_sz;
   extern unsigned pid_t_sz;
   extern unsigned timeval_sz;
   extern unsigned uid_t_sz;
   extern unsigned gid_t_sz;
   extern unsigned mbstate_t_sz;
   extern unsigned struct_timezone_sz;
   extern unsigned struct_tms_sz;

lib/sanitizer_common/sanitizer_platform_limits_posix.cc

#endif // !SANITIZER_IOS && !SANITIZER_FREEBSD
   unsigned struct_rusage_sz = sizeof(struct rusage);
   unsigned struct_tm_sz = sizeof(struct tm);
   unsigned struct_passwd_sz = sizeof(struct passwd);
   unsigned struct_group_sz = sizeof(struct group);
   unsigned siginfo_t_sz = sizeof(siginfo_t);
   unsigned struct_sigaction_sz = sizeof(struct sigaction);
   unsigned struct_itimerval_sz = sizeof(struct itimerval);
   unsigned pthread_t_sz = sizeof(pthread_t);
+  unsigned pthread_mutex_t_sz = sizeof(pthread_mutex_t);
   unsigned pthread_cond_t_sz = sizeof(pthread_cond_t);
   unsigned pid_t_sz = sizeof(pid_t);
   unsigned timeval_sz = sizeof(timeval);
   unsigned uid_t_sz = sizeof(uid_t);
   unsigned gid_t_sz = sizeof(gid_t);
   unsigned mbstate_t_sz = sizeof(mbstate_t);
   unsigned sigset_t_sz = sizeof(sigset_t);
   unsigned struct_timezone_sz = sizeof(struct timezone);

lib/tsan/rtl/tsan_interceptors.cc

 }
 #endif
 
 TSAN_INTERCEPTOR(int, pthread_once, void *o, void (*f)()) {
   SCOPED_INTERCEPTOR_RAW(pthread_once, o, f);
   if (o == 0 || f == 0)
     return errno_EINVAL;
   atomic_uint32_t *a;
-  if (!SANITIZER_MAC)
-    a = static_cast<atomic_uint32_t*>(o);
-  else  // On OS X, pthread_once_t has a header with a long-sized signature.
+
+  if (SANITIZER_MAC)
     a = static_cast<atomic_uint32_t*>((void *)((char *)o + sizeof(long_t)));
+  else if (SANITIZER_NETBSD)
+    a = static_cast<atomic_uint32_t*>
+          ((void *)((char *)o + __sanitizer::pthread_mutex_t_sz));
+  else
+    a = static_cast<atomic_uint32_t*>(o);
+
   u32 v = atomic_load(a, memory_order_acquire);
   if (v == 0 && atomic_compare_exchange_strong(a, &v, 1,
                                                memory_order_relaxed)) {
     (*f)();
     if (!thr->in_ignored_lib)
       Release(thr, pc, (uptr)o);
     atomic_store(a, 2, memory_order_release);
   } else {