lockdep: Fix backtraces

Truncate stupid -1 entries in backtraces.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1248096665.15751.8816.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 1cedb00..2f09702 100644 (file)
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -367,11 +367,21 @@ static int save_trace(struct stack_trace *trace)
 
        save_stack_trace(trace);
 
+       /*
+        * Some daft arches put -1 at the end to indicate its a full trace.
+        *
+        * <rant> this is buggy anyway, since it takes a whole extra entry so a
+        * complete trace that maxes out the entries provided will be reported
+        * as incomplete, friggin useless </rant>
+        */
+       if (trace->entries[trace->nr_entries-1] == ULONG_MAX)
+               trace->nr_entries--;
+
        trace->max_entries = trace->nr_entries;
 
        nr_stack_trace_entries += trace->nr_entries;
 
-       if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) {
+       if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {
                if (!debug_locks_off_graph_unlock())
                        return 0;