Merge tag 'perf-urgent-for-mingo-5.3-20190808' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

perf/urgent fixes:

db-export:

  Adrian Hunter:

  - Fix thread__exec_comm() picking of main thread COMM for pre-existing,
    synthesized from /proc data records.

annotate:

  Arnaldo Carvalho de Melo:

  - Fix printing of unaugmented disassembled instructions from BPF, some
    lines were leaving leftovers from the previous screen, due to use of
    newlines by binutils's libopcode disassembler.

perf ftrace:

  He Zhe:

  - Fix cpumask problems when only one CPU is present.

PMU events:

  Jin Yao:

  - Add missing "cpu_clk_unhalted.core" event.

perf bench:

  Jiri Olsa:

  - Fix cpu0 binding in the NUMA benchmarks.

s390:

  Thomas Richter:

  - Fix module size calculations.

build system:

  Masanari Iida:

  - Fix a typo in a variable name in the Documentation Makefile

misc:

  Ian Rogers:

  - Fix include paths in ui directory.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 873ab505ca80..590793cc5142 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -214,14 +214,24 @@ struct comm *thread__comm(const struct thread *thread)
 
 struct comm *thread__exec_comm(const struct thread *thread)
 {
-	struct comm *comm, *last = NULL;
+	struct comm *comm, *last = NULL, *second_last = NULL;
 
 	list_for_each_entry(comm, &thread->comm_list, list) {
 		if (comm->exec)
 			return comm;
+		second_last = last;
 		last = comm;
 	}
 
+	/*
+	 * 'last' with no start time might be the parent's comm of a synthesized
+	 * thread (created by processing a synthesized fork event). For a main
+	 * thread, that is very probably wrong. Prefer a later comm to avoid
+	 * that case.
+	 */
+	if (second_last && !last->start && thread->pid_ == thread->tid)
+		return second_last;
+
 	return last;
 }