[PATCH] i386: Do backtrace fallback too

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>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 14 insertions, 3 deletions

diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 313ac1f7dc5a..3facc8fcb91e 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -187,10 +187,21 @@ static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
                         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
                 }
         }