Diagnostic function rw_enter_diag() should be called before
WITNESS_CHECKORDER() to have proper locking/debugging information.
In the case of 'locking against myself' it is currently impossible
to know where the lock has been previously acquired. Diff below fixes
that, ok?
Index: kern/kern_rwlock.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_rwlock.c,v
retrieving revision 1.47
diff -u -p -r1.47 kern_rwlock.c
--- kern/kern_rwlock.c 8 Feb 2021 08:18:45 -0000 1.47
+++ kern/kern_rwlock.c 15 Feb 2021 10:32:57 -0000
@@ -237,7 +237,11 @@ rw_enter(struct rwlock *rwl, int flags)
int error, prio;
#ifdef WITNESS
int lop_flags;
+#endif
+
+ rw_enter_diag(rwl, flags);
+#ifdef WITNESS
lop_flags = LOP_NEWORDER;
if (flags & RW_WRITE)
lop_flags |= LOP_EXCLUSIVE;
@@ -270,8 +274,6 @@ retry:
continue;
}
#endif
-
- rw_enter_diag(rwl, flags);
if (flags & RW_NOSLEEP)
return (EBUSY);
