Index: src/os_unix.c
==================================================================
--- src/os_unix.c
+++ src/os_unix.c
@@ -8065,10 +8065,26 @@
   /* Register all VFSes defined in the aVfs[] array */
   for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){
     sqlite3_vfs_register(&aVfs[i], i==0);
   }
   unixBigLock = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1);
+
+  /* Validate lock assumptions */
+  assert( SQLITE_SHM_NLOCK==8 );  /* Number of available locks */
+  assert( UNIX_SHM_BASE==120  );  /* Start of locking area */
+  /* Locks:
+  **    WRITE       UNIX_SHM_BASE      120
+  **    CKPT        UNIX_SHM_BASE+1    121
+  **    RECOVER     UNIX_SHM_BASE+2    122
+  **    READ-0      UNIX_SHM_BASE+3    123
+  **    READ-1      UNIX_SHM_BASE+4    124
+  **    READ-2      UNIX_SHM_BASE+5    125
+  **    READ-3      UNIX_SHM_BASE+6    126
+  **    READ-4      UNIX_SHM_BASE+7    127
+  **    DMS         UNIX_SHM_BASE+8    128
+  */
+  assert( UNIX_SHM_DMS==128   );  /* Byte offset of the deadman-switch */
   return SQLITE_OK; 
 }
 
 /*
 ** Shutdown the operating system interface.