[PATCH 0/1] MR2701: ntdll: Decrement thread count from exit_thread and exit the process if needed.

[Tim Clem (＠tclem)]

The `nb_threads` counter in ntdll is decremented by `abort_thread` but not `exit_thread`, which is used when `NtTerminateThread` is called on the current thread. That results in `nb_threads` being off by one, so neither `abort_thread` nor `exit_thread` will notice when the final thread is killed or call `abort_process`/`exit_process` of its own volition.

In some instances that results in the final thread of a process hanging around and continuing to do work until it's killed by the server's SIGKILL timer. Since most of the process' internal state has been torn down by that point, that usually results in syscall faults or server `write` failures.

[PATCH 1/1] ntdll: Decrement thread count from exit_thread and exit the process if needed.

[Tim Clem]

From: Tim Clem

---
 dlls/ntdll/unix/thread.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/dlls/ntdll/unix/thread.c b/dlls/ntdll/unix/thread.c
index 9b0b5f7ce22..2c1bf3ca637 100644
--- a/dlls/ntdll/unix/thread.c
+++ b/dlls/ntdll/unix/thread.c
@@ -1442,7 +1442,9 @@ static DECLSPEC_NORETURN void exit_thread( int status )
             virtual_free_teb( teb );
         }
     }
-    signal_exit_thread( status, pthread_exit_wrapper, NtCurrentTeb() );
+
+    if (InterlockedDecrement( &nb_threads ) <= 0) exit_process( status );
+    else signal_exit_thread( status, pthread_exit_wrapper, NtCurrentTeb() );
 }