diff options
| -rw-r--r-- | gcc/ada/libgnarl/s-tposen.adb | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/gcc/ada/libgnarl/s-tposen.adb b/gcc/ada/libgnarl/s-tposen.adb index 9dff661..a7447b9 100644 --- a/gcc/ada/libgnarl/s-tposen.adb +++ b/gcc/ada/libgnarl/s-tposen.adb @@ -345,11 +345,17 @@ package body System.Tasking.Protected_Objects.Single_Entry is pragma Assert (Entry_Call.State /= Cancelled); + -- Note that we need to acquire Self_Id's lock before checking the value + -- of Entry_Call.State, even though the latter is specified as atomic + -- with a pragma. If we didn't, another task could execute the entry on + -- our behalf right between the check of Entry_Call.State and the call + -- to Wait_For_Completion, and that would cause a deadlock. + + STPO.Write_Lock (Self_Id); if Entry_Call.State /= Done then - STPO.Write_Lock (Self_Id); Wait_For_Completion (Entry_Call'Access); - STPO.Unlock (Self_Id); end if; + STPO.Unlock (Self_Id); Check_Exception (Self_Id, Entry_Call'Access); end Protected_Single_Entry_Call; |