1 files changed, 23 insertions, 27 deletions

diff --git a/runtime/stack-i386.c b/runtime/stack-i386.c
index 78f89b0d..ad101889 100644
--- a/runtime/stack-i386.c
+++ b/runtime/stack-i386.c
@@ -14,65 +14,61 @@ static int _stp_valid_stack_ptr(unsigned long context, unsigned long p)
 }
 
 /* DWARF unwinder failed.  Just dump intereting addresses on kernel stack. */
-static void _stp_stack_print_fallback(unsigned long context, unsigned long stack, int verbose)
+static void _stp_stack_print_fallback(unsigned long context, unsigned long stack, int verbose, int levels)
 {
 	unsigned long addr;
-	while (_stp_valid_stack_ptr(context, stack) &&
-               !_stp_pbuf_full()) {
+	while (levels && _stp_valid_stack_ptr(context, stack)) {
 		if (unlikely(_stp_read_address(addr, (unsigned long *)stack, KERNEL_DS))) {
 			/* cannot access stack.  give up. */
 			return;
 		}
-		_stp_func_print(addr, verbose, 0);
+		if (_stp_func_print(addr, verbose, 0))
+			levels--;
 		stack++;
 	}
 }
 
 static void __stp_stack_print (struct pt_regs *regs, int verbose, int levels)
 {
-	unsigned long *stack = (unsigned long *)&REG_SP(regs);
-	unsigned long context = (unsigned long)stack & ~(THREAD_SIZE - 1);
+	unsigned long context = (unsigned long)&REG_SP(regs) & ~(THREAD_SIZE - 1);
 
 #ifdef	STP_USE_FRAME_POINTER
-	/* FIXME: need to use _stp_func_print() and safe copy */
 	unsigned long addr;
-	
-#ifdef STAPCONF_X86_UNIREGS
-	unsigned long ebp = regs->bp;
-#else
-	unsigned long ebp = regs->ebp;
-#endif /* STAPCONF_X86_UNIREGS */
-	
-	while (_stp_valid_stack_ptr(context, (unsigned long)ebp) &&
-               !_stp_pbuf_full()) {
-		if (unlikely(_stp_read_address(addr, (unsigned long *)(ebp + 4), KERNEL_DS))) {
+	unsigned long next_fp, fp = REG_FP(regs);
+
+	while (levels && _stp_valid_stack_ptr(context, (unsigned long)fp)) {
+		if (unlikely(_stp_read_address(addr, (unsigned long *)(fp + 4), KERNEL_DS))) {
 			/* cannot access stack.  give up. */
 			return;
 		}
-		if (verbose) {
-			_stp_print_char(' ');
-			_stp_symbol_print (addr);
-			_stp_print_char('\n');
-		} else
-			_stp_printf ("0x%08lx ", addr);
-		ebp = *(unsigned long *)ebp;
+		_stp_func_print(addr, verbose, 1);
+		if (unlikely(_stp_read_address(next_fp, (unsigned long *)fp, KERNEL_DS))) {
+			/* cannot access stack.  give up. */
+			return;
+		}
+		levels--;
+
+		/* frame pointers move upwards */
+		if (next_fp <= fp)
+			break;
+		fp = next_fp;
 	}
 #else
 	struct unwind_frame_info info;
 	arch_unw_init_frame_info(&info, regs);
 	
-	while (!arch_unw_user_mode(&info) &&
-               !_stp_pbuf_full ()) {
+	while (levels && !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);
+			levels--;
 			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(context, UNW_SP(&info), verbose);
+			_stp_stack_print_fallback(context, UNW_SP(&info), verbose, levels);
 		break;
 	}
 #endif /* STP_USE_FRAME_POINTER */