diff --git a/winsup/cygserver/ChangeLog b/winsup/cygserver/ChangeLog
index 6de3a94ba..8f373e0d6 100644
--- a/winsup/cygserver/ChangeLog
+++ b/winsup/cygserver/ChangeLog
@@ -1,3 +1,7 @@
+2004-08-31  Corinna Vinschen  <corinna@vinschen.de>
+
+	* sysv_shm.cc (kern_shmat): Add debug_printf's.
+
 2004-08-24  Corinna Vinschen  <corinna@vinschen.de>
 
 	* bsd_mutex.cc (_msleep): Release process object while waiting.
diff --git a/winsup/cygserver/sysv_shm.cc b/winsup/cygserver/sysv_shm.cc
index 803e4395d..5daeb5cf3 100644
--- a/winsup/cygserver/sysv_shm.cc
+++ b/winsup/cygserver/sysv_shm.cc
@@ -382,6 +382,7 @@ kern_shmat(struct thread *td, int shmid, const void *shmaddr, int shmflg)
 	if ((shmflg & SHM_RDONLY) == 0)
 		prot |= VM_PROT_WRITE;
 	flags = MAP_ANON | MAP_SHARED;
+	debug_printf ("shmaddr: %x, shmflg: %x", shmaddr, shmflg);
 	if (shmaddr) {
 		flags |= MAP_FIXED;
 		if (shmflg & SHM_RND) {
@@ -389,6 +390,7 @@ kern_shmat(struct thread *td, int shmid, const void *shmaddr, int shmflg)
 		} else if (((vm_offset_t)shmaddr & (SHMLBA-1)) == 0) {
 			attach_va = (vm_offset_t)shmaddr;
 		} else {
+			debug_printf ("Odd shmaddr: EINVAL");
 			error = EINVAL;
 			goto done2;
 		}