tracing, sched, vfs: Fix 'old_pid' usage in trace_sched_process_exec()

1. TRACE_EVENT(sched_process_exec) forgets to actually use the
   old pid argument, it sets ->old_pid = p->pid.

2. search_binary_handler() uses the wrong pid number. tracepoint
   needs the global pid_t from the root namespace, while old_pid
   is the virtual pid number as it seen by the tracer/parent.

With this patch we have two pid_t's in search_binary_handler(),
not really nice. Perhaps we should switch to "struct pid*", but
in this case it would be better to cleanup the current code
first and move the "depth == 0" code outside.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: David Smith <dsmith@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Link: http://lkml.kernel.org/r/20120330162636.GA4857@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index fbc7b1ad929b..ea7a2035456d 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -295,7 +295,7 @@ TRACE_EVENT(sched_process_exec,
         TP_fast_assign(
                 __assign_str(filename, bprm->filename);
                 __entry->pid            = p->pid;
-                __entry->old_pid        = p->pid;
+                __entry->old_pid        = old_pid;
         ),
 
         TP_printk("filename=%s pid=%d old_pid=%d", __get_str(filename),