Explain why it sometimes looks like pass() fails.

[pintos-anon] / doc / debug.texi

diff --git a/doc/debug.texi b/doc/debug.texi
index 6432ca3a1fa530a9a13af7710a4d4f8d3f535ef1..8fbc7d53bd6b7bdcb16950754de7c47bd8fd70b5 100644 (file)
--- a/doc/debug.texi
+++ b/doc/debug.texi
@@ -119,9 +119,15 @@ Alternatively, it could be that the @file{kernel.o} you passed to
 the backtrace.
 
 Sometimes backtraces can be confusing without implying corruption.
-Compiler optimizations can cause surprising behavior.  For example, when
-a function has called another function as its final action (a @dfn{tail
-call}), the calling function may not appear in a backtrace at all.
+Compiler optimizations can cause surprising behavior.  When a function
+has called another function as its final action (a @dfn{tail call}), the
+calling function may not appear in a backtrace at all.  Similarly, when
+function A calls another function B that never returns, the compiler may
+optimize such that an unrelated function C appears in the backtrace
+instead of A.  Function C is simply the function that happens to be in
+memory just after A.  In the threads project, this is commonly seen in
+backtraces for test failures; see @ref{The pass function fails, ,
+@func{pass} Fails}), for more information.
 
 @menu
 * Backtrace Example::