Re: [PATCH, committed] [9/10/11 Regression] PR fortran/95104 - Segfault on a legal WAIT statement

[Thomas Koenig via Gcc-patches]

Hi Harald,

There are two possible fixes for this:

(1) guard the call to unlock_unit by:

diff --git a/libgfortran/io/transfer.c b/libgfortran/io/transfer.c
index cd51679ff46..296be0711a2 100644
--- a/libgfortran/io/transfer.c
+++ b/libgfortran/io/transfer.c
@@ -4508,7 +4508,8 @@ st_wait_async (st_parameter_wait *wtp)
         async_wait (&(wtp->common), u->au);
      }

-  unlock_unit (u);
+  if (u)
+    unlock_unit (u);
  }



(2) in unlock_unit():

diff --git a/libgfortran/io/unit.c b/libgfortran/io/unit.c
index 0030d7e8701..a3b0656cb90 100644
--- a/libgfortran/io/unit.c
+++ b/libgfortran/io/unit.c
@@ -767,9 +767,12 @@ close_unit_1 (gfc_unit *u, int locked)
  void
  unlock_unit (gfc_unit *u)
  {
-  NOTE ("unlock_unit = %d", u->unit_number);
-  UNLOCK (&u->lock);
-  NOTE ("unlock_unit done");
+  if (u)
+    {
+      NOTE ("unlock_unit = %d", u->unit_number);
+      UNLOCK (&u->lock);
+      NOTE ("unlock_unit done");
+    }
  }

  /* close_unit()-- Close a unit.  The stream is closed, and any memory


Does anybody prefer one over the other, or just commit both (which might be
preferable to catch other unguarded cases)?

I think the second one is more robust - like you say, this may catch
other cases.  If we have that one, we don't need the first one.

Regards

        Thomas