[PATCH for 2.6.18rc2] [7/7] i386: Do backtrace fallback too

[PATCH for 2.6.18rc2] [7/7] i386: Do backtrace fallback too

[Andi Kleen]

Similar patch to earlier x86-64 patch. When the dwarf2 unwinder fails
dump the left over stack with the old unwinder.

Also some clarifications in the headers.

Signed-off-by: Andi Kleen <ak@suse.de>

---
 arch/i386/kernel/traps.c |   17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

Index: linux/arch/i386/kernel/traps.c
===================================================================
--- linux.orig/arch/i386/kernel/traps.c
+++ linux/arch/i386/kernel/traps.c
@@ -187,10 +187,21 @@ static void show_trace_log_lvl(struct ta
 			if (unwind_init_blocked(&info, task) == 0)
 				unw_ret = show_trace_unwind(&info, log_lvl);
 		}
-		if (unw_ret > 0) {
-			if (call_trace > 0)
+		if (unw_ret > 0 && !arch_unw_user_mode(&info)) {
+#ifdef CONFIG_STACK_UNWIND
+			print_symbol("DWARF2 unwinder stuck at %s\n",
+				     UNW_PC(info.regs));
+			if (call_trace == 1) {
+				printk("Leftover inexact backtrace:\n");
+				if (UNW_SP(info.regs))
+					stack = (void *)UNW_SP(info.regs);
+			} else if (call_trace > 1)
 				return;
-			printk("%sLegacy call trace:\n", log_lvl);
+			else
+				printk("Full inexact backtrace again:\n");
+#else
+			printk("Inexact backtrace:\n");
+#endif
 		}
 	}