Merge branch 'master' of ssh://sources.redhat.com/git/systemtap

1 files changed, 31 insertions, 6 deletions

diff --git a/runtime/stack-x86_64.c b/runtime/stack-x86_64.c
index 186b2ad4..9915c594 100644
--- a/runtime/stack-x86_64.c
+++ b/runtime/stack-x86_64.c
@@ -1,6 +1,6 @@
 /* -*- linux-c -*-
  * x86_64 stack tracing functions
- * Copyright (C) 2005, 2006, 2007 Red Hat Inc.
+ * Copyright (C) 2005-2008 Red Hat Inc.
  *
  * This file is part of systemtap, and is free software.  You can
  * redistribute it and/or modify it under the terms of the GNU General
@@ -8,13 +8,38 @@
  * later version.
  */
 
-static void __stp_stack_print (struct pt_regs *regs, int verbose, int levels)
+/* DWARF unwinder failed.  Just dump intereting addresses on kernel stack. */
+static void _stp_stack_print_fallback(unsigned long stack, int verbose)
 {
-	unsigned long *stack = (unsigned long *)REG_SP(regs);
 	unsigned long addr;
+	while (stack & (THREAD_SIZE - 1) &&
+               !_stp_pbuf_full()) {
+		if (unlikely(_stp_read_address(addr, (unsigned long *)stack, KERNEL_DS))) {
+			/* cannot access stack.  give up. */
+			return;
+		}
+		_stp_func_print(addr, verbose, 0);
+		stack++;
+	}
+}
+
+static void __stp_stack_print(struct pt_regs *regs, int verbose, int levels)
+{
+	// FIXME: large stack allocation
+	struct unwind_frame_info info;
+	arch_unw_init_frame_info(&info, regs);
 
-	while ((long)stack & (THREAD_SIZE-1)) {
-		addr = *stack++;
-		_stp_func_print(addr, verbose, 1);
+	while (!arch_unw_user_mode(&info)) {
+		int ret = unwind(&info);
+		dbug_unwind(1, "ret=%d PC=%lx SP=%lx\n", ret, UNW_PC(&info), UNW_SP(&info));
+		if (ret == 0) {
+			_stp_func_print(UNW_PC(&info), verbose, 1);
+			continue;
+		}
+		/* If an error happened or we hit a kretprobe trampoline, use fallback backtrace */
+		/* FIXME: is there a way to unwind across kretprobe trampolines? */
+		if (ret < 0 || (ret > 0 && UNW_PC(&info) == _stp_kretprobe_trampoline))
+			_stp_stack_print_fallback(UNW_SP(&info), verbose);
+		break;
 	}
 }