terminate backtrace for main thread

diff --git a/src/threads/start.S b/src/threads/start.S
index fe2200b80384ebb7a050b2294488b325a6c0c8d6..92e7fb8a281b7833071c4b8aa6da19e32e2faee7 100644 (file)
--- a/src/threads/start.S
+++ b/src/threads/start.S
@@ -173,6 +173,7 @@ start:
        mov %ax, %gs
        mov %ax, %ss
        addl $LOADER_PHYS_BASE, %esp
+    movl $0, %ebp
 
 #### Call main().