Fixed corruption of the "blocked" list in lf_setlock() when tsleep()

returns 0 after ptrace() attach and/or detach doesn't quite quite
deliver a signal.  Perhaps the process shouldn't be woken in this
case, but avoiding the problem is easy.

PR:		12247

Fixed a couple of places where mechanical fixing of compiler warnings
caused misspelling of NOLOCKF as NULL.

1 files changed, 20 insertions, 17 deletions

diff --git a/sys/kern/kern_lockf.c b/sys/kern/kern_lockf.c
index 4655f6a..21f38e2 100644
--- a/sys/kern/kern_lockf.c
+++ b/sys/kern/kern_lockf.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)ufs_lockf.c	8.3 (Berkeley) 1/6/94
- * $Id: kern_lockf.c,v 1.21 1999/01/27 21:49:56 dillon Exp $
+ * $Id: kern_lockf.c,v 1.22 1999/05/08 22:46:46 dt Exp $
  */
 
 #include "opt_debug_lockf.h"
@@ -272,20 +272,22 @@ lf_setlock(lock)
 			lf_printlist("lf_setlock", block);
 		}
 #endif /* LOCKF_DEBUG */
-		if ((error = tsleep((caddr_t)lock, priority, lockstr, 0))) {
-                        /*
-			 * We may have been awakened by a signal (in
-			 * which case we must remove ourselves from the
-			 * blocked list) and/or by another process
-			 * releasing a lock (in which case we have already
-			 * been removed from the blocked list and our
-			 * lf_next field set to NOLOCKF).
-                         */
-			if (lock->lf_next)
-				TAILQ_REMOVE(&lock->lf_next->lf_blkhd, lock,
-					lf_block);
-                        free(lock, M_LOCKF);
-                        return (error);
+		error = tsleep((caddr_t)lock, priority, lockstr, 0);
+		/*
+		 * We may have been awakened by a signal and/or by a
+		 * debugger continuing us (in which cases we must remove
+		 * ourselves from the blocked list) and/or by another
+		 * process releasing a lock (in which case we have
+		 * already been removed from the blocked list and our
+		 * lf_next field set to NOLOCKF).
+		 */
+		if (lock->lf_next) {
+			TAILQ_REMOVE(&lock->lf_next->lf_blkhd, lock, lf_block);
+			lock->lf_next = NOLOCKF;
+		}
+		if (error) {
+			free(lock, M_LOCKF);
+			return (error);
 		}
 	}
 	/*
@@ -360,7 +362,8 @@ lf_setlock(lock)
 			    overlap->lf_type == F_WRLCK) {
 				lf_wakelock(overlap);
 			} else {
-				while ((ltmp = overlap->lf_blkhd.tqh_first) != NULL) {
+				while ((ltmp = overlap->lf_blkhd.tqh_first) !=
+				    NOLOCKF) {
 					TAILQ_REMOVE(&overlap->lf_blkhd, ltmp,
 					    lf_block);
 					TAILQ_INSERT_TAIL(&lock->lf_blkhd,
@@ -718,7 +721,7 @@ lf_wakelock(listhead)
 {
 	register struct lockf *wakelock;
 
-	while ((wakelock = listhead->lf_blkhd.tqh_first) != NULL) {
+	while ((wakelock = listhead->lf_blkhd.tqh_first) != NOLOCKF) {
 		TAILQ_REMOVE(&listhead->lf_blkhd, wakelock, lf_block);
 		wakelock->lf_next = NOLOCKF;
 #ifdef LOCKF_DEBUG