From 2f217659a45a04a5f4b78855bf18a4e64bc04840 Mon Sep 17 00:00:00 2001
From: Juho Snellman <jsnell@iki.fi>
Date: Tue, 17 Apr 2007 06:54:10 +0000
Subject: [PATCH] 1.0.4.93: backtrace_from_fp

        * Split the ldb x86oid backtrace into two parts (backtrace and
          backtrace_from_fp), to make debugging e.g. thread deadlocks
          from gdb easier. For example: call backtrace_from_fp($rbp, 10)
---
 src/runtime/backtrace.c |   49 ++++++++++++++++++++++++++++++++++-------------
 version.lisp-expr       |    2 +-
 2 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/src/runtime/backtrace.c b/src/runtime/backtrace.c
index b4503ad..07114aa 100644
--- a/src/runtime/backtrace.c
+++ b/src/runtime/backtrace.c
@@ -284,15 +284,26 @@ backtrace(int nframes)
 #else
 
 static int
+altstack_pointer_p (void *p) {
+    char* stack_start = ((char *) arch_os_get_current_thread())
+        + dynamic_values_bytes;
+    char* stack_end = stack_start + 32*SIGSTKSZ;
+
+    return (p > stack_start && p <= stack_end);
+}
+
+static int
 stack_pointer_p (void *p)
 {
   /* we are using sizeof(long) here, because that is the right value on both
    * x86 and x86-64.  (But note that false positives would not cause much harm
    * given the heuristical nature of x86_call_context.) */
   unsigned long stack_alignment = sizeof(long);
-  return (p < (void *) arch_os_get_current_thread()->control_stack_end
-          && p > (void *) &p
-          && (((unsigned long) p) & (stack_alignment-1)) == 0);
+
+  return (altstack_pointer_p(p)
+          || (p < (void *) arch_os_get_current_thread()->control_stack_end
+              && (p > (void *) &p || altstack_pointer_p(&p))
+              && (((unsigned long) p) & (stack_alignment-1)) == 0));
 }
 
 static int
@@ -511,20 +522,15 @@ print_entry_points (struct code *code)
   }
 }
 
+/* This function has been split from backtrace() to enable Lisp
+ * backtraces from gdb with call backtrace_from_fp(...). Useful for
+ * example when debugging threading deadlocks.
+ */
 void
-backtrace(int nframes)
+backtrace_from_fp(void *fp, int nframes)
 {
-  void *fp;
   int i;
 
-#if defined(LISP_FEATURE_X86)
-  asm("movl %%ebp,%0" : "=g" (fp));
-#elif defined (LISP_FEATURE_X86_64)
-  asm("movq %%rbp,%0" : "=g" (fp));
-#else
-#error "How did we get here?"
-#endif
-
   for (i = 0; i < nframes; ++i) {
     lispobj *p;
     void *ra;
@@ -563,4 +569,21 @@ backtrace(int nframes)
   }
 }
 
+void
+backtrace(int nframes)
+{
+  void *fp;
+  int i;
+
+#if defined(LISP_FEATURE_X86)
+  asm("movl %%ebp,%0" : "=g" (fp));
+#elif defined (LISP_FEATURE_X86_64)
+  asm("movq %%rbp,%0" : "=g" (fp));
+#else
+#error "How did we get here?"
+#endif
+
+  backtrace_from_fp(fp, nframes);
+}
+
 #endif
diff --git a/version.lisp-expr b/version.lisp-expr
index 4fac3a1..3d44c11 100644
--- a/version.lisp-expr
+++ b/version.lisp-expr
@@ -17,4 +17,4 @@
 ;;; checkins which aren't released. (And occasionally for internal
 ;;; versions, especially for internal versions off the main CVS
 ;;; branch, it gets hairier, e.g. "0.pre7.14.flaky4.13".)
-"1.0.4.92"
+"1.0.4.93"
-- 
1.7.10.4