From: Ben Pfaff <blp@cs.stanford.edu>
Date: Mon, 10 Nov 2008 04:07:40 +0000 (-0800)
Subject: Make backtraces slightly more reliable.
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?p=pintos-anon;a=commitdiff_plain;h=bb940d21474958a1d8ee2abffdcb6bac27918398

Make backtraces slightly more reliable.

We now ignore pointers that are not null but still clearly wild.

We could check that there's really a valid PDE and PTE (I think Linux
does this) but it would take more code and be ugly.
---

diff --git a/src/lib/debug.c b/src/lib/debug.c
index 6d7c9e1..1dc1bf8 100644
--- a/src/lib/debug.c
+++ b/src/lib/debug.c
@@ -17,7 +17,7 @@ debug_backtrace (void)
   
   printf ("Call stack:");
   for (frame = __builtin_frame_address (0);
-       frame != NULL && frame[0] != NULL;
+       (uintptr_t) frame >= 0x1000 && frame[0] != NULL;
        frame = frame[0]) 
     printf (" %p", frame[1]);
   printf (".\n");