perf thread-stack: Fix thread stack processing for the idle task

perf creates a single 'struct thread' to represent the idle task. That
is because threads are identified by PID and TID, and the idle task
always has PID == TID == 0.

However, there are actually separate idle tasks for each CPU. That
creates a problem for thread stack processing which assumes that each
thread has a single stack, not one stack per CPU.

Fix that by passing through the CPU number, and in the case of the idle
"thread", pick the thread stack from an array based on the CPU number.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20181221120620.9659-8-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 88d52ed85ffc..d079f36d342d 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -1182,7 +1182,7 @@ static int perf_sample__fprintf_callindent(struct perf_sample *sample,
                                            struct addr_location *al, FILE *fp)
 {
         struct perf_event_attr *attr = &evsel->attr;
-        size_t depth = thread_stack__depth(thread);
+        size_t depth = thread_stack__depth(thread, sample->cpu);
         const char *name = NULL;
         static int spacing;
         int len = 0;
@@ -1716,7 +1716,7 @@ static bool show_event(struct perf_sample *sample,
                        struct thread *thread,
                        struct addr_location *al)
 {
-        int depth = thread_stack__depth(thread);
+        int depth = thread_stack__depth(thread, sample->cpu);
 
         if (!symbol_conf.graph_function)
                 return true;