VG_(get_strace_wrk): don't segfault in the degenerate case fp_min =

fp_max_orig = 0.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@7551

diff --git a/coregrind/m_stacktrace.c b/coregrind/m_stacktrace.c
index f1073e20c2b85c16849591e5b9ed106c6d208b75..2f5bb097e800c3ed7dbab9b7872f6fcb39f68ac0 100644 (file)
--- a/coregrind/m_stacktrace.c
+++ b/coregrind/m_stacktrace.c
@@ -90,7 +90,8 @@ UInt VG_(get_StackTrace_wrk) ( ThreadId tid_if_known,
    // current page, at least.  Dunno if it helps.
    // NJN 2002-sep-17: seems to -- stack traces look like 1.0.X again
    fp_max = VG_PGROUNDUP(fp_max_orig);
-   fp_max -= sizeof(Addr);
+   if (fp_max >= sizeof(Addr))
+      fp_max -= sizeof(Addr);
 
    if (debug)
       VG_(printf)("n_ips=%d fp_min=%p fp_max_orig=%p, "