perf sched latency: Fix thread pid reuse issue

The latency subcommand holds a tree of working atoms sorted by thread's
pid/tid. If there's new thread with same pid and tid, the old working atom is
found and assert bug condition is hit in search function:

  thread_atoms_search: Assertion `!(thread != atoms->thread)' failed

Changing the sort function to use thread object pointers together with pid and
tid check. This way new thread will never find old one with same pid/tid.

Link: http://lkml.kernel.org/n/[email protected]
Reported-by: Mohit Agrawal <[email protected]>
Signed-off-by: Jiri Olsa <[email protected]>
Acked-by: Namhyung Kim <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 0ee6d900e100a29ceeb3cacf7e97d81dce8f8d17..e3d3e32c0a934dc8fd5ce207073f3b80ecf4361a 100644 (file)
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -1203,12 +1203,13 @@ static void output_lat_thread(struct perf_sched *sched, struct work_atoms *work_
 
 static int pid_cmp(struct work_atoms *l, struct work_atoms *r)
 {
+       if (l->thread == r->thread)
+               return 0;
        if (l->thread->tid < r->thread->tid)
                return -1;
        if (l->thread->tid > r->thread->tid)
                return 1;
-
-       return 0;
+       return (int)(l->thread - r->thread);
 }
 
 static int avg_cmp(struct work_atoms *l, struct work_atoms *r)